Professor Trim's - pages 24/8/06 10:00 Page i
PROFESSOR TRIM’S BECOMING SLIMMER
Professor Trim's - pages 24/8/06 10:00 Page ii
PROFESSOR TRIM’S PROFESSORS Professor John Blundell PhD C Psychol. MBPS, Professor of Bio-Psychology, Leeds University, UK and Board Member of the International Association for the Study of Obesity (IASSO) Professor Wendy Brown BSc (Hons), MSc, Dip Phys Ed, PhD Professor of Physical Activity and Health, University of Queensland Professor Ian Caterson MBBS BSc (Med) PhD FRACP Boden Professor of Human Nutrition, Sydney University and Vice President, International Association for the Study of Obesity Professor Terry Dwyer MBBS, MPH, MD, FAFPHM Director Menzies School of Health Sciences Hobart, and University of Tasmania Professor Garry Egger MPH PhD MAPS Director, Centre for Health Promotion and Research Sydney Adjunct Professor of Health Sciences, Deakin University Professor Kerin O’Dea BSc, PhD Director of Menzies School of Health Research, Darwin Professor Stephan Rossner MD, PhD Director, Obesity Research Program, Luddinge Hospital, Stockholm, Sweden and Past President of the International Association for the Study of Obesity (IASSO)
Professor Boyd Swinburn MD, MBChB, FRACP Professor of Population Health and Nutrition, Deakin University
Professor Trim's - pages 24/8/06 10:00 Page iii
PROFESSOR TRIM’S BECOMING SLIMMER THE WEIGHT-LOSS PROGRAM
for women Dr Garry Egger By the originator of the ‘GutBusters’ waist-loss program
Professor Trim's - pages 24/8/06 10:00 Page iv
First published in 2003 Copyright © Garry Egger 2003 All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without prior permission in writing from the publisher. The Australian Copyright Act 1968 (the Act) allows a maximum of one chapter or 10% of this book, whichever is the greater, to be photocopied by any educational institution for its educational purposes provided that the educational institution (or body that administers it) has given a remuneration notice to Copyright Agency Limited (CAL) under the Act. Allen & Unwin 83 Alexander Street Crows Nest NSW 2065 Australia Phone: (61 2) 8425 0100 Fax: (61 2) 9906 2218 Email:
[email protected] Web: www.allenandunwin.com National Library of Australia Cataloguing-in-Publication entry: Egger, Garry. Professor Trim’s becoming slimmer: weight loss for women. Includes index. ISBN 1-74114-018-8 1. Weight loss. 2. Women—Nutrition. 3. Physical fitness for women. I. title. 613.7045 Set in 11/12.5 pt Adobe Garamond by Midland Typesetters, Maryborough, Victoria Printed by Griffin Press, South Australia 10 9 8 7 6 5 4 3 2 1
Professor Trim's - pages 24/8/06 10:00 Page v
CONTENTS Preface
vii
Chapter 1 The hype vs the reality
1
Chapter 2 Biology matters
5
Chapter 3 Behaviour matters
19
Chapter 4 Environment matters
38
Chapter 5 Nutrition news
48
Chapter 6 Moving and losing
84
Chapter 7 Maintaining your losses
106
Chapter 8 The good, the bad and the ugly
123
Appendix
143
Other books on the subject by Garr y Egger
145
Notes
146
Index
157
v
Professor Trim's - pages 24/8/06 10:00 Page vi
Professor Trim's - pages 24/8/06 10:00 Page vii
PREFACE
h t . r l e a o u s d c i f v y n m T g h p l a o r t s c e x m d n f y b i , r v h w o t l e a A m . — g i d n s y o t b e r u c q l a f , n p m i s ’ v h e t o A . r c x l y d p n m i a s g t o h e W E C A F R P Weight control is a simple yet complex matter. At one level it’s simple, because all it requires is to eat less and move more. At another level, however, it is one of the most complex aspects of human physiology. There are so many factors other than eating and exercise that can influence body weight—many of them beyond the control of the individual. To complicate matters, weight management varies between individuals, according to their genes, ethnicity, gender, behaviour and other, often unknown, factors. For many women, in particular, the problem can become a cyclical one: dieting to lose weight causes anxiety and depression; anxiety and depression lead to overeating; and overeating to more weight gain. So knowing all about nutrition and exercise is often not enough. Ironically, weight loss often involves giving yourself permission to eat. As with forbidden fruit, food often becomes an object of desire, irrespective of the biological drive to eat. For some women, early experiences such as physical or sexual abuse or undue pressure to conform to an unrealistic body image lead to an obsession with weight, which more often than not results in gaining rather than losing weight. As a member of the World Health Organisation’s program for obesity management in the developing world and of several Government committees on weight control and obesity management in Australia, I realised many years ago that women and men were like different species when it came to gaining and losing body weight. For the survival of the species, it is much more important for women to be able to store fat and maintain it under circumstances in which men would lose it rapidly. Women’s role in reproduction means they have to last the nine long months of pregnancy. For most of this time, men are more or less immaterial to the process. Men’s fat stores around their potbelly are simply an extra packet of sandwiches designed to get them through hard times when there’re no vii
Professor Trim's - pages 24/8/06 10:00 Page viii
BECOMING SLIMMER
kangaroos to catch. As such, this fat comes and goes easily. When I started the GutBusters program for men in 1990, I avoided the more difficult physiological, sociological and psychological issues involved in why women get fat and concentrated on the pure education of men—giving them the information and letting them get on with it. However, the success of GutBusters led to many partners of GutBuster men asking for a ‘women’s version’ of the program. Although the name is hardly feminine, these women claimed that they had tried all the other women’s programs and just wanted what they saw happening to their men folk. Yet we at GutBusters knew that our program would only work for a small proportion of women. If we were to do it right, we would have to incorporate the knowledge base of the GutBuster program in a program that was much more psychologically and physically attuned to women. This approach was initially developed as part of a program called Trim for Life, for which this book was originally written. The time came, however, for GutBusters to move on. It became obvious by the turn of the millennium that men and women need to be involved in managing obesity, the world’s biggest epidemic. It also became clear that the best mechanism for conducting a nationwide program would be to enlist the support of those trained to provide the first step in primary health care— the nation’s general practitioners. As I had been involved in teaching over 25% of the country’s GPs in a program on Weight Control and Obesity Management developed through Sydney University, here was the ideal opportunity to offer a shared-care approach to weight control for men, women, families, diabetics, pregnant mothers and others with specific needs. The overall initiative goes by the name of Professor Trim’s Medically Supervised Weight Loss Programs, with Becoming Slimmer the program designed for women and Becoming Gut Less the one for men. Within these programs women and men can work with a specially trained GP on a full year’s program of instruction and guidance, including the services of a medically selected personal trainer. This book represents only a part of the women’s Becoming Slimmer program. You can apply for the full program through your GP or via the Internet at www.professortrim.com, or you can simply use this book as a guide to inform and help you improve your own diet and lifestyle. Becoming Slimmer is designed to complement the information on the CD and in the workbooks in the Becoming Slimmer program. The book follows a model of weight control developed by myself and Professor Boyd Swinburn of Deakin University, providing a range of up-to-date scientifically supported facts to help you lose weight and maintain that loss in the viii
Professor Trim's - pages 24/8/06 10:00 Page ix
PREFACE
long term. While the book alone is not meant to constitute a weight management program as such, I think you will find that it presents you with new things to consider and perhaps incorporate in your own approach to weight management. I wish you all the best.
Calories or kilojoules? The traditional measure of ‘energy’ has been a ‘calorie’, which is the amount of heat energy required to raise the temperature of 1 g of water 1°C. As a calorie is a very small unit, we generally talk in terms of 1000 calories or a kilocalorie (written as 1 kcal). More recently, the metric measure of kilojoules is being used as a measure of energy: 1 kilocalorie = 4.2 kilojoules (written kJ).
ix
Professor Trim's - pages 24/8/06 10:00 Page x
Professor Trim's - pages 24/8/06 10:00 Page 1
Chapter 1 THE HYPE
VS
THE REALITY
WHY LONG-TERM WEIGHT LOSS IS SO ELUSIVE Everywhere you turn there’s someone trying to sell you something, usually cloaked in technical jargon and promising ‘amazing’, ‘fantastic’ or ‘unbelievable’ results from a product or program with a previously undiscovered ‘magic’ or ‘secret’ ingredient. Little wonder the average consumer is bewildered. Like all health fads, weight control promises follow the course of least resistance. Everybody wants to be slim. Moreover, they want it overnight. However, the creeping pandemic of obesity in modern western societies has meant that most of us are slowly getting fatter instead. The average rate of weight gain in the western world over the past 15 years, for example, has been 1 g per day, or roughly 1 kg every three years. Now 53% of women and 67% of men in Australia—and even more in North America—are regarded as overweight or obese, and these percentages are increasing by around 1% per year. Weight control scams have always been ubiquitous. But under these conditions, they’re almost as prolific as the problem they claim to solve. The simple fact that the population is getting fatter suggests that nothing that has been tried to date works—at least not on a large scale. This, in turn, suggests that we’ve been looking at the problem in the wrong way. Just maybe our stock solution and our knee-jerk reaction to needing to shed weight, dieting, is the wrong way to approach the problem. More to the point, it could very well be one of the causes. Similarly, all our ideas about exercise for fitness and sports performance might not bear sufficient relation to the type of exercise needed for fat loss. If this is the case, maybe we’ve been barking up the wrong tree entirely. Perhaps all our beliefs about weight loss need a good shake-up. To some extent this is already happening. The body of scientific research in the field of obesity and body fatness has grown enormously in recent times. So much so that it would not be untrue to say that there has been 1
Professor Trim's - pages 24/8/06 10:00 Page 2
BECOMING SLIMMER
more published scientifically on the topic in the past two decades than in all of modern history before that. As a result, we’re learning heaps. But much of this information lies locked up in universities and research establishments, while quick-buck marketers have a field day with pseudo-science confusion.
CHANGING THE MODEL FOR WEIGHT LOSS What is clear is that the old model of body weight, which was based simply on energy balance—the difference between the amount of energy taken in (food) and the amount of energy used up (exercise)—is wrong. This is a physics-type model, which admits of no flexibility, and no reaction of the human body to change. Notions such as calorie counting and dieting, which have evolved from this way of thinking, are equally outdated. It might be comforting for you to know at the outset that the vast majority of popular magazine ‘diet of the week’ programs are not only useless, they can be downright counterproductive! A new model has to consider the dynamic adjustments that the body makes any time there’s a change in energy balance, and which, in the long term, often serve to prevent any long-term loss of weight. These are adjustments such as increases in appetite with increased exercise, or decreases in metabolic rate with decreased food intake. Changes like this are designed to maintain the status quo in the face of changing conditions—an obviously desirable characteristic in times of scarcity, but not so useful in times of excess. A new model for conceptualising weight management has to take into account the total environment as well as the genetic and behavioural characteristics of the individual. We know that genes are important, but we also know that the genetic predisposition to obesity is unlikely to be fully manifest in an inhospitable environment. . . . the vast majority of popular magazine ‘diet of the week’ programs are not only useless, they can be downright counterproductive! Finally, a new approach has to consider recent nutrition and exercise research, which shows that it’s the type more than the amount of food eaten that is important, and the duration rather than the intensity of exercise performed that has the greatest overall impact on energy balance and burning up fat stores. A model incorporating all of these components is shown in Figure 1.1. 2
Professor Trim's - pages 24/8/06 10:00 Page 3
THE HYPE
VS
THE REALITY
Figure 1.1: An ‘ecological’ paradigm for weight control
INFLUENCES Biology + Behaviour + Environment Body = fat stores
Fat/energy Fat/energy – expenditure intake MEDIATORS
x
Physiological adjustment MODERATORS
Source: Egger, G. and Swinburn, B. 1997. ‘An “ecological” approach to the obesity epidemic’, British Medical Journal, 315: 477–80.
This book is a collection of accepted scientific principles within each of the components of the model in Figure 1.1. Each chapter represents a different component of the model and corresponds to a session of ‘Professor Trim’s Becoming Slimmer’ program. I’ve avoided the faddist practice of preaching ‘amazing’ results from any of the suggestions within this book. All of them need to be considered carefully within the context of a healthy lifestyle, and I afford no special prominence to any particular tip.
MAKING CHANGES TO LOSE WEIGHT To lose weight, by definition, requires change. And there are really only two types of change that are effective. These are eating differently and moving more. All weight gains are effected through changes in energy balance, so that more energy is taken in (food) than is expended (exercise and metabolic rate). However, these changes in energy balance can be activated by mechanisms that might seem totally unrelated to diet and exercise. Depression, for example, can lead to eating more and moving less; lack of activity can cause a drop in metabolic rate, which leads to an increase in fat storage. Unduly restrictive dieting can lead to intense hunger, which is then overcompensated for by binge eating. Therefore, while psychological and other 3
Professor Trim's - pages 24/8/06 10:00 Page 4
BECOMING SLIMMER
factors play a significant role in weight gain, the final outcome depends on changes in eating and exercise. . . . there are really only two types of change that are effective. These are eating differently and moving more. You’ll notice that eating differently and moving more don’t imply eating less or exercising more, in the traditional sense of these statements. Within these two approaches there are numerous recommendations that can help to effect a lasting change in energy balance. This book presents a select group of recommendations, which have convincing scientific support. Each tip presented is meant to stand on its own. So if you want to pick up the book at meal time, between kids’ baths or even while in the smallest room of the house, you can dip into it anywhere. Of course, conforming to all of the principles in the book might be tough, but it will guarantee a good, healthy, long-term body weight, as well as all the secondary benefits you will get as a result of incorporating techniques that work—changes that do improve your weight and overall health. But, if adhering to them all proves too much, then certainly take what you can comfortably use . . . and perhaps build on the changes to your eating habits and lifestyle one at a time. You’ll probably find that just having a better (and correct!) understanding of what influences your weight and health will act as motivation for you to take up more and more of these changes.
4
Professor Trim's - pages 24/8/06 10:00 Page 5
Chapter 2 BIOLOGY MATTERS
INTRODUCTION There are some things in life you can change, and some you can’t. Biology falls largely in the latter category. However, knowing how biology affects body weight might help you to understand why your body reacts as it does to your attempts to keep your weight under control, and why the next person’s reaction could be completely different. In the first place, there are genetic differences. Not only do we know that we inherit general characteristics from our parents, but recent advances in molecular biology have isolated many of the genes that actually cause this effect in relation to body weight. By the turn of the millennium, over 50 genes had been specifically identified as being associated with obesity.1 The scramble is now on to synthesise some of their products (proteins, which usually have a ‘signalling’ role in the body) so a magic elixir can be produced in the form of a tablet. So far, this result has been elusive, but science is full of surprises. Gender is the second biological influence. Because of their important reproductive function, females have been privileged by nature to be more efficient than males at storing and conserving energy-rich body fat. Fat is stored in different parts of the body in females and males, and responds to attempts to reduce it in different ways. There are some tricks that might help to negotiate these obstacles but, again, just knowing that this is so might be enough to make some women feel more comfortable with their existing dimensions. Gender is also important when it comes to particular gender-related life phases, such as pregnancy and contraception. You will find some tips on managing these stages in this chapter. A third biological factor we need to consider is aging. Physiological changes with aging make fat easier to gain and more difficult to lose. However, there are also gender-based differences in aging, with older (postmenopausal) women shifting their pattern of body fatness from primarily on the lower body to the upper body. These and other changes mean we 5
Professor Trim's - pages 24/8/06 10:00 Page 6
BECOMING SLIMMER
Testing your genes Answer the following four questions to see if your genes can be blamed for your body weight. For measurement purposes here, the term ‘overweight’ means having a BMI (where BMI = weight (in kg) divided by height (in metres), squared) over 25, ‘obese’ means a BMI over 30 and ‘very obese’ a BMI over 40. For example, someone 170 cm tall and weighing 75 kg would have a BMI of 26 (75 ÷ (1.7)2 = 26). 1. As far as you know, were either or both of your parents obese or very obese for most of their lives? Neither/Don’t know/No Yes, one parent Yes, both parents
Obese 0 7 14
Very Obese 0 14 28
2. Do you have any first-degree relatives who have been obese for most of their lives? Score 2 points for every obese immediate family member up to a maximum of 10 points. 3. How would you describe the average BMI of your siblings? Not obese (30) 6
Very obese (>40) 12
4. When did you first become overweight and/or obese? Never Before age 10 Before age 20 Before age 30
Overweight 0 20 10 5
Obese 0 30 20 10
Scores: 35%, fortified) Fudge, not chocolate, plain Pretzels, regular Biscuit, fruit, polyunsaturated, wholemeal Bread stick, hard Muesli, toasted Mousse, low-fat, chocolate, artificially sweetened Rice cake with corn and sesame Turkish delight, chocolate-coated Confectionary, carob-coated, sugar
Fat g/100 7.6 4.2 0.5 3.4 3.8 4.9 4.2 4.2 7.2 9.9 3.8 9.8 5.0 2.5 9.8 9.9
ED kcals/g (kJ/g) 3.5 (14.9) 3.5 (14.8) 3.7 (15.6) 3.7 (15.6) 3.8 (16.1) 3.8 (16.0) 3.8 (16.1) 3.8 (16.1) 3.8 (15.8) 3.9 (15.9) 3.9 (16.3) 3.9 (16.2) 3.9 (15.0) 3.9 (15.0) 4.0 (16.6) 4.2 (17.5)
DECREASE TOTAL ENERGY How much food do you really need? The first stage of estimating how much food you need is measuring your resting metabolic rate (RMR). This is done through detailed and complicated laboratory analyses, or it can be estimated using formulas such as those for males and females set out in Table 5.1 (at page 51). Even a 50 kg woman requires around 1300 kcals (5460 kJ)per day to balance metabolism in the resting state. Special calculations are needed to estimate the extra requirements for physical activity carried out throughout the day. Table 5.5 shows the energy required at different levels of exertion by multiplying metabolic rate by Physical Activity Level or PAL. 57
Professor Trim's - pages 24/8/06 10:00 Page 58
BECOMING SLIMMER
Table 5.5 Energy intake required at various activity levels Chair- or bed-bound RMR x 1.2 Seated with no option of moving and little exercise RMR x 1.4–1.5 Seated at work, needing to move around but little strenuous exercise RMR x 1.6–1.7 Standing work (e.g. housework, shop assistant) RMR x 1.8–1.9 Strenuous work or highly active leisure RMR x 2.0–2.4
To lose weight, a standard approach is to decrease food needed for maintenance (RMR + PAL) by around 500 kcals (2100 kJ) a day. This should lead to a weight loss of 0.5 kg a week (at least for the first few weeks).65
Choose low glycaemic index (GI) foods Although energy density can affect the total amount of energy we consume, food that is absorbed slowly can work to reduce the total amount of energy consumed. The Glycaemic Index (GI) is a relatively new concept in nutrition, used to explain the rate of absorption of various foods.66 Because of their more complex structure, starches are digested more slowly than sugars. So it’s been thought that these would be particularly beneficial in managing a disease such as diabetes, and for weight loss. But recently it’s been shown that digestion and metabolism are not so simple. Some carbohydrates are not broken down just according to their ‘simple’ or ‘complex’ nature. Another measure has been developed to explain this. The Glycaemic Index (GI) is a method of classifying the glycaemic (or blood sugar) response to carbohydrate-rich foods. Put another way, it’s a measure of how quickly carbohydrate reaches the bloodstream. Foods can be tested and rated out of 100 according to their GI measure. Foods closer to 100 are more quickly digested, so in general it’s best to consume foods with a lower GI rating. Not all sweet, sugary foods will be absorbed quickly and therefore have a high GI. It’s far more complex than that, and depends on a number of characteristics of the food consumed. For example: •
58
Glucose (GI = 100) has a higher GI than fructose (GI = 20). So temperate fruits (apples, pears, oranges), which have a high fructose content, have a lower GI than tropical fruits (watermelon, rockmelon, mangoes).
Professor Trim's - pages 24/8/06 10:00 Page 59
NUTRITION NEWS
•
•
•
•
The ratio of two types of starches (amylose:amylopectin) in a food can affect its GI. Amylopectin is more easily digested than amylose. Therefore foods such as legumes, with their high amylose: amylopectin ratio, have a lower GI than rice, which has a higher amylopectin content. Processing can increase the GI of a food. Wholemeal bread, where the grains have been ground down and incorporated into the dough, is more quickly digested (and therefore has a higher GI) than a whole grain bread, where the grains are still intact. Soluble fibre (such as gums in fruits) can decrease the rate of absorption of glucose and thus decrease GI. Fibre supplements have not been found to have the same effect because the fibre is not contained within food and so doesn’t slow absorption. Large amounts of fat can slow down digestion. While this results in a low GI for foods that contain both carbohydrate and fat (such as ice-cream), the fat content should be the primary consideration when making food selections.
Low GI foods are scored below 55, intermediate from 55 to 70 and high, above 70. You can combine a high and low GI food to produce an intermediate GI meal. The use of low GI foods can be a useful addition to a reduced-fat, high-fibre eating plan. Table 5.6 Glycaemic Index of selected foods (foods with a lower GI are likely to be better for effective weight control, assuming fat is also controlled) Bread Bagel Crumpet Mixed grain bread (av) White bread (av)
72 69 45 70
Croissant Fruit loaf (white) Rye bread Wholemeal (av)
67 47 50 77
Breakfast Cereals Kellogg’s All BranTM Kellogg’s CornflakesTM Kellogg’s SustainTM Muesli – untoasted
30 77 68 56
Sanitarium Weet-BixTM Kellogg’s NutrigrainTM Kellogg’s Mini WheatsTM Porridge
75 66 58 42
Grains/Pasta Buckwheat
54
Noodles – instant
47 59
Professor Trim's - pages 24/8/06 10:00 Page 60
BECOMING SLIMMER Rice – calrose – Basmati – brown
83 58 76
Pasta – egg fettuccine – ravioli (meat) – spaghetti
32 39 41
Biscuits/Cakes Puffed crispbread Water cracker Shredded wheatmeal Apple muffin
81 78 62 44
Ryvita Arrowroot Shortbread Sponge cake
69 69 64 46
Vegetables Carrots Potato – baked – new – pontiac
49 85 62 56
Parsnip Sweet potato Peas (green) Sweet corn
97 54 48 55
Legumes Baked beans Butter beans Kidney beans
48 31 27
Broad beans Chick peas Soya beans
79 33 18
Fruit Banana Grapefruit Mango
53 25 55
Cherries Grapes Orange
22 43 43
Snacks Corn chips Popcorn
72 55
Peanuts Potato crisps
14 54
Dairy Foods Milk – whole – skim
27 32
Yoghurt flavoured, low-fat Ice-cream
33 61
DECREASE FAT Exclude, modify, substitute or replace It’s up to you! There’s an infinite combination of foods to make up an eating plan for successful weight control. To help categorise the available options, Dr Allan Kristal and his colleagues in Seattle have come up with a fourfactor method of reducing fat in the diet.67 They suggest: 60
Professor Trim's - pages 24/8/06 10:00 Page 61
NUTRITION NEWS
1. Exclude, or eliminate, certain foods or food preparation techniques: • • • •
don’t put butter or margarine on toast avoid sausages or luncheon meats eat salads without mayonnaise or dressing avoid fried foods.
2. Modify, or alter, foods so that they are lower in fat: • • • •
trim fat off meat grill rather than frying skim fat off soups drain fat off cooked mince.
3. Substitute, by using reduced-fat or low-fat varieties of regular foods: • • • •
choose reduced-fat cheeses have skim milk instead of full-cream milk use lean mince eat reduced-fat ice-cream.
4. Replace foods, or change to new foods or ingredients: • • • •
use lemon juice instead of salad dressing eat yoghurt instead of ice cream have fruit rather than a piece of cake baste meats with vegetable stock instead of oil.
Break the fat addiction Research done at the Monell Chemical Senses Centre in Philadelphia has shown that cutting back on fat can reduce the pleasure derived from eating fatty foods.68 Scientists experimented with three groups of people: one eating a normal, generally high-fat diet, a second on a fat-restricted diet, and a third on low-fat substitutes for fatty foods within a normal diet. . . . cutting back on fat can reduce the pleasure of fatty foods. The groups were tested on their pleasure ratings in response to a range of foods for twelve weeks while they were on the diet and again for twelve weeks after it was finished. At the end of the initial period, the researchers found a decrease in ‘hedonic’ ratings, or the degree of appeal of fatty foods in the two groups with restricted fat intake. They also noticed a decrease in 61
Professor Trim's - pages 24/8/06 10:00 Page 62
BECOMING SLIMMER
overall energy intake, and a decrease in body weight in these groups, compared with the normal diet group. At the end of the post-test period (twelve weeks later) the intake of fats and expressed satisfaction derived from eating fatty foods was still low in the lowfat diet group, but not in the group using low-fat replacement foods. The implications of this study are that while fats might be addictive and might help increase total calorie intake in the diet, restricting their use can break their addictiveness. So don’t think that you can trick your body or mind by substituting low-fat equivalents for fatty foods. While this tactic certainly does make for a healthier diet and is a better way to go than eating the ‘real’ thing, you’ll find that cutting down on the food type is the only way to stop an addiction to it.
Give toddlers their due Reduced-fat eating is now recommended for adults and adolescents. However, it’s important to remember that you can’t simply apply what’s good for one group to another—diets low in fat can compromise the growth of important nerve tissue in younger children. Speaking at the Sixth European Conference on Obesity in Copenhagen in 1995, Dr Michelle Rolland-Cachera, from L’Hopital St Lazare in Paris, claimed there could be a drop in growth potential for young children on limited-fat diets.69 Infants require a high level of fat for their energy needs, as well as for the myelination, or ‘coating’, of nerve fibres. Breast milk caters for this well, as it has a fat content of around 50%. . . . a low fat intake should be avoided in the early childhood years to guarantee optimal growth. A high fat intake is not always a bad thing, according to Dr RollandCachera. In fact, a low fat intake should be avoided in the early childhood years in order to guarantee optimal growth.
Don’t cut out all fats Some fats are very healthy! Unfortunately, the message to reduce fat can be read as ‘. . . all fats are bad’. This is certainly not the case. Your body needs a minimum amount of fat for essential fatty acids, which make nerve cells and hormones and help transport and absorb fat-soluble vitamins A, D, E and K. Scientists are accumulating evidence to suggest that some fats are in fact beneficial for combating problems such as heart disease and some cancers. The latest in the fish oils saga is a good example. A Seattle study of people with heart disease has shown that people who eat 62
Professor Trim's - pages 24/8/06 10:00 Page 63
NUTRITION NEWS
fish at least once a week have about half the risk of a heart attack of those who don’t eat fish at all.70 If this is so, it is likely to be explained by the fact that fish oils seem to make the blood less clottable and sticky. They might also make the heart muscle more stable and less prone to the type of abnormal rhythm that can lead to cardiac arrest. The Seattle study is one of many indicating benefits from regularly eating fish rich in omega-3 polyunsaturated fats. A practical recommendation for health is to aim for at least two fish meals a week. Oils or spreads made from olive oil or canola oil also get the thumbs up from health authorities. If you use added fat, these are the oils of choice. While olive oil is over three-quarters mono-unsaturated fatty acids, canola oil has a significant omega-3 content. A recent entrant to the market, ‘Sunola’ oil, has the highest mono-unsaturated fat content, at 85%. The effects of different oils on health might be varied. The effects on body weight, however, are likely to be more consistent (with the possible exception of fish oils), because all fats and oils have the equivalent of 9 kcals (38 kJ) per gram.
Cut out butter and margarine Spreads such as butter and margarine have become popular more for social reasons and as a matter of convention than anything else. Some cultures don’t bother with spreads at all. As a result, they don’t take in the high amounts of fat that come with regular spreads on bread and toast.71 A reasonable serving of butter or margarine on a slice of bread is the equivalent of around 5 g. As about 80% of this is fat (in butter and margarine—it’s just the type of fat that is different), you’re adding about 4 g of fat or 36 kcals (151 kJ) of energy to every piece of bread you eat. Just say you take in around 8 to10 slices per day (including sandwiches), this amounts to 32–40 g of fat, or 288–360 kcals (1210–1512 kJ) of energy— or about 10% of your daily energy intake! Toast is probably even more of a worry, because spreads sink into warm toast. With butter in particular, this usually means that you have to use more to give you that ‘lacquered’ effect. You could wind up with the equivalent of about half a kilo of fat every ten days—just from the spreads under your Vegemite or marmalade! Going off or at least reducing spreads, whether butter or margarine, is a good way of eliminating fat without too much hardship.
Develop a lifestyle eating plan Fat in food is high in energy (9 kcals/38 kJ per gram versus 4 kcals/17 kJ per gram for carbohydrate or protein). And fat is stored in the body with greater efficiency. Fat also tends to increase rather than decrease the appetite and the total amount of food that is eaten at a sitting. So reducing fat in the 63
Professor Trim's - pages 24/8/06 10:00 Page 64
BECOMING SLIMMER
diet is now accepted as being perhaps the single most effective measure for controlling obesity. But whether this can be done without a strictly planned, low-fat diet regimen is open to question. In contrast with volitional eating, diet plans that involve people being told what foods to eat in minimal amounts have traditionally been the order of the day. But research from the Agricultural University in Denmark72 suggests this should stop. Scientists were investigating a food program in which a group of men and women were told where the fats were in the foods they were eating and then asked to keep these foods to a minimum. Those on this program were compared with a group of controls on a standard modern diet after eleven weeks and it was found that those on the program actually lost more weight, even though they consumed no fewer total calories! This weight loss was also quite clearly from fat rather than muscle stores, suggesting a greater long-term maintenance of fat loss since a reduction of fat is less likely to lower metabolic rates. Those with the highest levels of fat at the beginning of the program also achieved the greatest fat losses, again a move in the right direction. In assessing their results, the Danish researchers pointed out the inadequacies of weight-reducing ‘diets’. They suggested that by reducing the fat in their diet, people can avoid obsessive calorie counting but still lose weight, and in a healthy manner. . . . by reducing the fat in their diet, people can avoid obsessive calorie counting but still lose weight, and in a healthy manner.
Find out where fat hides When something looks and feels fatty, chances are it is. But today there’s a huge selection of processed foods that have varying appearances and textures. Studies suggest that identifying fat content in foods is difficult. For example, consumer research carried out recently by the Australian Dairy Corporation compared the actual fat content of various foods with consumers’ knowledge of that fat content. Interestingly, levels of fat in food were estimated by consumers to be higher than they actually were for a range of fatty foods such as chips (52% perceived, compared with 32% actual), meat pie (45% to 14%) and sausages (47% to 17%), but less high for some other food products, such as popcorn (consumers thought 5%, compared to an actual content of 20%). Another study revealed that people commonly misclassify many foods.73 In this study, men and women were again asked to estimate the fat content of various foods. They dramatically underestimated the fat content for some 64
Professor Trim's - pages 24/8/06 10:00 Page 65
NUTRITION NEWS
foods, while for others they went the other way. Foods commonly misclassified as being higher in fat than they are included potato, pasta, baked beans and beer. Foods perceived to be lower in fat than they are included chicken with the skin, sardines, cheese and peanuts. Almost 70% of subjects thought that margarine was lower in fat than butter. These findings underpin the importance of recognising the fat content of foods.
Check your figures Selecting foods for fat content should become easier as more food manufacturers put nutrition information panels on their products. From a dietary fat perspective, the most important number is the amount of fat per 100 g. The lower the better. And for those who need a guideline, try choosing foods with less than 10 g fat per 100 g of food.74 Table 5.7 compares nutrition information for two foods; potato crisps and oven-baked pretzels. There’s a big difference in fat content, and it’s obvious the pretzel would be the better choice for a savoury snack. Table 5.7 Sample nutrition information panel Nutrition Information
Size of pack Serving size Energy Protein Fat Carbohydrate Total Sugars Dietary fibre Sodium Potassium Cholesterol
Food 1 Crisps 100 g 50 g
Food 2 Pretzels 100 g 30 g
545 kcals (2290 kJ) 6.1 g 37.1 g
386 kcals (1620 kJ) 10 g 3g
51.0 g 0.4 g 5.6 g
81.1 g 4.0 g 0g
1600 mg 965 mg 0 mg
670 mg 1230 mg 0 mg
This arbitrary cut-off point of 10 g/100 g needs to be flexible, especially in the case of cheese, where the many reduced-fat varieties still have around 24 g fat per 100 g. It’s also important to check that the serving size quoted on the 65
Professor Trim's - pages 24/8/06 10:00 Page 66
BECOMING SLIMMER
pack is realistic. For example, a 200 ml tub of regular yoghurt has about 8 g of fat which, when added to the daily fat intake, can be quite significant.
Decode ingredient lists Where ingredient quantities are not given, manufacturers are required by law to state on labels the ingredients, listed in decreasing order by volume. To overcome listing fats high on the ingredient list, some manufacturers show these as individual fats, which are less by volume. A general principle is to avoid foods where fats constitute any of the first three ingredients. Fats can go under many names. A list of the common ones is given below.
Common names for fats on food labels Lard, animal fat, animal shortening, coconut oil, palm oil, vegetable oil, butterfat, whole milk solids, copha, tallow, chocolate, chocolate chips, shortening, margarine, cocoa butter.
Watch out for fat–sugar combinations Fats in foods are more of a worry for weight gain than sugars. But a combination of the two might be cause for even greater concern. There are a couple of reasons for this. First, the fat–sugar combination makes it easier to get the food into your mouth. A study of 1700 women found that the main risk from sugar in the diet is that it’s used to make high-fat products such as cakes, biscuits and chocolate more palatable.75 The research showed that most sugar eaten by these women was not as added sugar but ‘hidden’ in processed foods. The sweet, fatty foods they ate tended to be at the expense of fruit and vegetables. Once inside the body this ‘bliss-point’ mixture might facilitate greater fat storage. Studies have recently been done on fat disappearance rates, or the rate at which fats in foods are used up in the body as energy. These show that after eating fatty foods, such as ice-cream with sugar (such as a caramel topping), blood fats in the form of triglycerides are slower to disappear from the bloodstream than after eating either ice-cream alone or sugar alone. This suggests that the body is likely to store fat more readily if it is accompanied by sugars. Other research has shown a similar effect with a fat–alcohol combination. The intervals that should be left between eating these kinds of foods, however, is unknown. So while, as a discerning waist watcher, you should look out for fat, you should probably be even more wary of combining it with either alcohol or sugar. 66
Professor Trim's - pages 24/8/06 10:00 Page 67
NUTRITION NEWS
High-fat foods during the day Rather than having to watch fat intake all day long, there might be key times to be more conscious of what you eat. Research at the National Institute of Health in Maryland in the US shows that fat intake varies during the course of a day.76 Examining food diaries of a large sample of women, researchers found that most have a very controlled fat intake early in the day. Even those women who have high daily fat intake apparently eat less of it at the morning meal and in snacks, and more of it than lower fat eaters at lunch and dinner. This implies that a ‘low-fat’ breakfast can easily be achieved, but restricting fat intake at later meals can be more of a challenge. Focusing on the fat content of lunch or dinner might be a more productive strategy, and one that could have significant (and sustainable) effects for some people.
Fat substitutes In 1990, 10% of food products were labelled either low fat, or no fat, obviously capitalising on market demand. But because fat is tasty, the prize awaits whoever develops the best no-fat, fatty-tasting substitute. Basically, there are three types of fat substitutes currently available: 1. Protein-based fat substitutes. These are usually made from milk and/or egg white proteins, sugar, pectin and citric acid (for example, Simplesse). They have the disadvantage of being heat sensitive and therefore unsuitable for use in cooking. 2. Carbohydrate-based fat substitutes. These can be in either digestible or indigestible form, and are usually made from starches. They feel like oil in the mouth because of their ability to form heat-stable gels. However, as with protein-based products, they can’t be used for frying. 3. Fat-based fat substitutes. These are modified-fat alternatives and, although they still provide calories, they can be effective in small amounts. They’re mostly used in soft confectionery and can reduce the calorie content of baked and filled dairy products, but probably won’t satisfy the fat craving. The surge in fat substitutes has given rise to concern about their safety. With standard food ingredients, testing is subject to a rigid set of experimental criteria where 100 times the normal quantity is fed to animals over an extended period. But unlike most food additives, which are consumed only in small quantities, fat substitutes could replace a substantial proportion of the diet for some people. Safety is therefore difficult to guarantee from animal research.77 67
Professor Trim's - pages 24/8/06 10:00 Page 68
BECOMING SLIMMER
There does appear to be potential in the diet for low-fat substitutes, but for now the jury is still out. In the meantime, it might be advisable to use low-fat substitutes with caution and ‘watch this space’.
If you like chips, make them low fat Potato chips are one of the most tempting morsels on any careful food eater’s list. But they’re also disastrous in terms of fat and energy content. There are ways, however, of lowering the fat content and keeping the taste.78 Here are some of them: •
•
•
•
•
68
Use frozen, not thawed chips. Potato chips that are pre-cut and frozen form an instant crust when dropped in oil, thus minimising water loss and fat absorption. Thawed chips release more water into the surrounding oil and lower the oil temperature, therefore requiring more cooking and more absorption of fat. Cook at the right temperature. The best temperature for cooking lower fat chips is between 180°C and 185°C. Cooking chips at a lower temperature prevents the formation on the chip surface of the crust that prevents excessive fat absorption. Estimates suggest that 40% more fat is absorbed when the temperature is 10% lower than the recommended cooking temperature. Cooking at excessively high temperatures can change the nature of the oil and make it less healthy. Use poly- or mono-unsaturated oils. The fat content of chips is affected by the type of oil in which they are cooked. Stable oils with a high level of mono-unsaturated fats, such as Sunola oil (from sunflower seeds), are known to be relatively stable and longlasting. Other apparently healthy choices, such as cottonseed oil and soybean-based oils, are less stable and more susceptible to undesirable changes at the recommended cooking temperatures. Maintain the quality of the oil. Older oil/fat is characterised by a darkness in colour and a tendency to smoke. Older oils inhibit the formation of the crust on chips that reduces fat absorption. Oils should be discarded regularly and not overused, as continual heating can change the oil to include more ‘trans’ fatty acids, which are as unhealthy as saturated fats. Use the right type of chip. Absorption of fat during cooking is affected by the surface area of the chip. Because of its greater surface area, a crinkle-cut chip is likely to absorb more fat and therefore have a higher fat content than a plain chip. Bigger chips also have less surface area to total volume than small, thin chips.
Professor Trim's - pages 24/8/06 10:00 Page 69
NUTRITION NEWS
INCREASE FIBRE Fill up on fibre Fibre is the part of carbohydrate that resists breakdown by enzymes in the intestine. Most fibre passes through to the large bowel, ready for excretion in the faeces. You can therefore eat fibre without absorbing any energy from it. The benefits of eating foods that contain fibre have a lot to do with energy density. (This term refers to the number of calories in a given weight of food. See pages 56–7 for further details on ED.) Many foods that are naturally high in fibre have low energy density. In contrast, many fast foods laden with fat and little or no fibre have high energy density. If you were to eat two meals, both with the same amount of energy, the high-fat meal would be much smaller and consumed a lot faster. A recent review of effects of energy density on obesity concluded that ‘a low-fat, low energy dense diet results in a spontaneous fall in energy intake while maintaining feelings of satiety’.79 This means that you can eat less fat and less energy and still avoid the ‘. . . perpetual hunger that often accompanies active periods of food restriction’. As with most modifications to your diet, moderation is important. While too little fibre can cause constipation, too much, especially in the form of wheat bran, can decrease the absorption of iron and zinc, which are important minerals. It can also make you a little unpleasant to be around—if you get my drift! Around 30–40 g of fibre a day is what you should be aiming for.
Put (resistant) starch back on the menu Once thought to be a primary cause of obesity, starchy foods are now thought to have the opposite effect. But not all starches are the same, says Professor Alison Stephens, an expert in carbohydrate metabolism from the University of Satkatchewan in Canada.80 ‘The re-emergence of starchy foods (or non-fibre-complex carbohydrates) and their influence in health is making the interest in fibre a little old fashioned’, says Stephens. Recently, attention has turned to a form of starch in foods called ‘resistant’ starch because it is not easily digested in the intestine. Raw potato and green bananas are the best (although somewhat unpalatable) examples of this, and research comparing digestion of these has shown that not only do they add fewer calories to the diet, they also appear to cause an increase in fat use instead of glucose use by the body. Researchers from the prestigious Centre for Food Research in Denmark suggest resistant starches might have an effect on fat burning similar to 69
Professor Trim's - pages 24/8/06 10:00 Page 70
BECOMING SLIMMER
abstaining from eating, because they are not digested quickly and burned as energy, so fat is used instead. These starches could also have major benefits for diabetics and people who suffer from other metabolic disorders. The recently introduced high-fibre white breads are a good source of resistant starch. There’ll be more on these foods in future research.
Eat more fruit and vegetables For years, health authorities have been encouraging us to eat more fruit and vegetables. The CSIRO Division of Human Nutrition in Adelaide, for example, recommends at least three serves of fruit and four serves of vegetables each day for health and weight control.81 Vegetables have the lowest energy density of all the food groups. The average carrot provides only 24 kcals (101 kJ), with 3 g of fibre and no fat. Fruit contains a little more energy from natural sugars, mostly fructose. Contrary to what some people believe, bananas have very little fat (less than one-fifth of a gram). The odd fruit out is the avocado. Munching on several avocados a day will add significantly to fat intake (about 40 g per avocado), even though it contains healthy, mono-unsaturated fat. In contrast, using avocado as a sandwich spread instead of margarine is a good way to cut back on fat. If this is not enough, the increasing volume of scientific evidence linking fruit and vegetable consumption with reduced risk of various cancers is another plus for eating extra fruit and vegetables.
Eat the fruit rather than drink the juice If you’ve been drinking a glass of fruit juice at breakfast for longer than you can remember, you’re probably a bit concerned after reading this heading. Well, don’t be. But do take into consideration some of the waist-wise advantages of whole fruit over juice. Since it takes around 0.5 kg of fruit to make a cup of fruit juice, the sugar (and therefore energy) value of the juice becomes highly concentrated, and very easy to consume. On the other hand, it’s quite filling to eat the whole fruit from which it came.82 . . . don’t drink anything you can eat whole (with the possible exception of (low-fat) cow’s milk! As we’ve said, dietary fats are always the first thing to cut back on in a weight control plan. After this, it’s a good idea to check for excessive sugar. If you’re drinking a litre of orange juice a day, the sugar can add up and might need to be considered. For that reason, a good principle is ‘don’t drink anything you can eat whole (with the possible exception of cow’s milk!)’. 70
Professor Trim's - pages 24/8/06 10:00 Page 71
NUTRITION NEWS
If you can’t live without your juice in the morning, at least make sure you expend some energy—juice it by hand!
Make breakfast a priority Physiologically speaking, it’s easy to see why eating carbohydrate shortly after rising is a good way to go (literally, too!). Blood glucose levels fall overnight, and without an early ‘recharge’ they can drop further as the day wears on. People who miss breakfast have the potential to get very hungry, very quickly. This intense feeling of hunger can compromise wise food choices and lead to overconsumption of fatty foods. High-fibre breakfast cereals have been found to delay the onset of hunger for longer than cereals with lower fibre contents. Getting more fibre from breakfast cereals has also been associated with choosing better sources of fibre during the day. Add to this the findings that breakfast eaters have lower fat intake, smoke less and get more vitamin C, and you can appreciate why having breakfast is an integral part of a healthy lifestyle and weight control program.83
Eat foods that bring satiety, not satiation Satiation is the feeling of fullness at a meal; satiety is satisfaction some time later. Fatty foods provide a low level of ‘satiation’, but a high level of ‘satiety’.84 This means that you can eat more during a meal without feeling full (have you noticed that it’s always possible to slip in some extra chocolate or a fatty dessert after a meal?). Satiety is generally greater some time after a meal of fatty foods, but this doesn’t prevent us eating more than we need to at the time. High-carbohydrate and fibre-rich foods, on the other hand, provide high levels of satiation, as well as relatively high satiety. This means that less is likely to be eaten at the meal, because you’re more likely to feel full. So a meal high in carbohydrate and fibre is likely to result in less hunger, as well as less energy being taken in, than a meal high in fat.
Choose foods that fill you up Foods are generally rated on their nutrient value—fat, carbohydrate and protein—with those trying to lose weight often advised to cut back on fats or carbohydrates. However, a new food index has now been developed that suggests that this approach might not be best in practice. Dr Susannah Holt, from the CSIRO Human Nutrition Unit, developed the measure, called a ‘satiety index’, at Sydney University.85 It’s expected to play a significant role in future weight loss and diabetes control programs. As part of her research, Dr Holt fed a number of different foods to a group of people, then rated how satisfied they felt, or their 71
Professor Trim's - pages 24/8/06 10:00 Page 72
BECOMING SLIMMER
level of ‘satiety’, every 15 minutes over a two-hour period. She then compared how much each ate after this period when allowed free access to food. Dr Holt compared the ‘satiety’ ratings of each food to bread, which was given a satiety index (SI) score of 100. The foods found to be highest on the SI score were not those that are most craved. In fact, foods high in fat (which also have the highest energy value) often had the lowest SI, meaning they’re not really filling even though they might be very tasty. The likely outcome? You feel like more. One of the highest SI scores given so far is that for boiled potatoes (average SI = 323). Other carbohydrates, such as porridge, fruit, pasta and even jellybeans, also rated high (see Table 5.8). Croissants, which are high in fat, have the lowest SI so far (SI = 47), possibly explaining why that rich, Sunday morning breakfast leaves you hungry for more. In contrast the protein, fibre and water content of a food tends to make it more filling. Sugar doesn’t seem to pose as much of a problem as fat, suggesting that satisfying a craving with sweets might be better than doing so with fats. Table 5.8 The satiety level of different foods
Bread Potatoes Porridge Oranges Apples Brown pasta Steak HoneysmacksTM Jellybeans
Low-fat foods
Potato chips Peanuts Mars BarTM Donuts Cake Croissant
High-fat foods
0
50
100
150
200
250
Satiety Index Score (%)
72
300
350
Professor Trim's - pages 24/8/06 10:00 Page 73
NUTRITION NEWS
KEEP PROTEIN RELATIVELY HIGH Keep protein levels high A decrease in food intake has consistently been shown to slow down metabolism by between 10% and 20%, and a big drop can even occur in the first 24 hours of an energy-restricted diet. This is likely to have a considerable effect on your total energy expenditure, and therefore on your weight loss. This dramatic drop in metabolic rate is a normal physiological response to sudden changes in body mass; it is designed to protect you against starvation. Now, research carried out at the Rowett Research Institute in Scotland suggests that maintaining protein intake while decreasing total energy intake might maintain muscle mass and thus protect metabolic rate.86 Studying a small group of men and women in a metabolic chamber, where energy expenditure can be accurately assessed, the researchers examined changes in metabolic rate after a seven-day diet using high-protein, then normal-protein and high-fat and finally high-carbohydrate diets. Each person was tested on each of the diets over a seven-day period, with a seven-day ‘wash out’ between. All of the diets fed a total of 1000 kcals (4200 kJ) multiplied by 1.4 times the metabolic rate of the individual. The high-protein diet contained 36% protein, compared with 15% protein in the other diets. The remaining 64% was divided equally between carbohydrate and fat. The high-carbohydrate diet had 53% carbohydrate and the high-fat diet had 53% fat. Although the diets were too short (seven days) to arrive at any noticeable differences in body weight, there were big differences in metabolic rate. On high protein, there was no decrease in metabolic rate, whereas there was a 3.5% decrease in metabolic rate on the high-carbohydrate mix and a 5% decrease on the high-fat diet. This amounted to an energy difference between the high-protein and the other diets of around 45 kcals (189 kJ) a day. The reason for energy output maintenance with high protein would appear to be the smaller proportion of lean body mass (muscle) lost with the diet; this helps to maintain a high metabolism. A total of 45 kcals (189 kJ) a day might not seem much, but it could be significant over time because it could counteract further declines in metabolic rate. Apparently, in any energy restriction, particularly low fat for fat loss, protein levels should be kept high. Good sources of high protein, low-fat energy, such as seafood, beans and lentils, might be useful for this purpose. 73
Professor Trim's - pages 24/8/06 10:00 Page 74
BECOMING SLIMMER
DECREASE PORTION SIZE Watch your por tion size Far too many people think that if they cut back on fat in their diet they can eat as much as they like. Of course this denies the second law of thermodynamics, which says that ‘energy is neither gained nor lost, it just changes form’. Portion size is important.87 You might not have noticed, but fast food takeaways have larger average portion sizes these days. Instead of getting a standard serve, you get a kingsize serve, because that’s a better way of marketing than dropping the price. You’ll also be asked if ‘you’d like fries with that’ to add to the total amount you’ll eat. Cutting back on portion size is the next thing you’ll have to look at if cutting back on fat and increasing fibre hasn’t worked. Try to keep your plate down to a reasonable size, and don’t go for extras.
Beware of compensator y overeating The human body is exceedingly cunning in its attempts to retain body fat, even in the presence of increased energy expenditure. Because fat is a valuable energy source that can help you survive in times of food scarcity, the body tries hard to preserve the fat it has. In essence, it’s saying to you ‘I’m alright at this weight, thank you. At least I’m alive, and I’ve got some spare energy just in case I need it. And I’m going to fight hard to keep it.’ . . . female humans, like female rats, tend to overeat after exercise to compensate for the energy burned up, whereas male humans, more like male rats, tend simply to decrease their body weight. One of the mechanisms by which this occurs is energy compensation. In active people, food intake tends to increase to compensate for the energy used up during exercise. Athletes, for example, eat up to four times what non-active people eat. However, they usually burn this off during exercise. Non-athletes might be a little less well regulated and might even balance their energy output with extra food input, thus maintaining a higher than wanted level of body fat. The problem is worse in females. Swedish researchers in the 1980s found that female humans, like female rats, tend to overeat after exercise to compensate for the energy burned up, whereas male humans, more like male 74
Professor Trim's - pages 24/8/06 10:00 Page 75
NUTRITION NEWS
rats, tend simply to decrease their body weight. More recently, these findings have been repeated with human subjects in research carried out at Leeds University in the UK.88 You might need to pay special attention to overeating when you introduce an exercise regime into your weight management program. However, it’s not clear whether such efforts can overcome the biological drive to eat to maintain body fat, particularly in the case of women whose body fat reserves are required for reproduction.
DECREASE ALCOHOL Trade of f drinks Restrictive diets don’t work because of the risk of rebound bingeing. Giving up alcohol can have a similar effect: if abstaining results in a psychological battle to stay off it, this can be counterproductive. You have to feel comfortable that any change you make is manageable. When asked about adopting healthy habits, most people clearly indicate that they want as little disruption of their lifestyle as possible.89 Rather than becoming non-drinkers, they’d prefer to do extra physical activity to burn off the energy from drinks. This makes sense, and allows a drink to be enjoyed even more when it’s deserved. How much is too much? The World Health Organisation has classified drinking levels: consuming less than two standard drinks a day might pose no health risk; daily consumption of more than two drinks for women and four for men can be potentially hazardous.
Beware the post-alcohol binge! Although it’s not well documented in scientific literature, there’s abundant anecdotal evidence to suggest that the craving for fats and sweets is increased after a night of alcohol consumption. The reasons for this are not clear; nor is it possible to say at this stage whether or not it can be controlled. However, an awareness of the problem might just help to reduce its effects by helping you alter your post-alcohol eating patterns, if necessary.90 It’s now well known that fats in foods are the real bugbear. Sweets, without fats, don’t seem to have the same potential for body fat storage. Therefore, post-alcohol cravings might be satisfied with sweet but low-fat foods, such as jellybeans, jubes, meringue or dried fruits such as dates or prunes. 75
Professor Trim's - pages 24/8/06 10:00 Page 76
BECOMING SLIMMER
There’s no guarantee this will work. But it is worth a try to help you though these danger periods. Table 5.9 What is a standard drink? A standard drink is that amount of an alcoholic beverage that contains 10 grams of alcohol: 375 ml can of ‘low alcohol’ beer 285 ml glass of regular beer 100 ml glass of wine 60 ml glass of fortified wine 30 ml nip of spirits
Alcohol by itself isn’t fattening Contrary to popular opinion, beer doesn’t give men their bellies. Alcohol per se doesn’t make you fat. It’s what you have with the alcohol that does this. This evidence comes from a number of quarters: in the first place, there’s good epidemiological data to show an inverse association between body weight and alcohol consumption in many countries.91 This is particularly so with females. . . . there’s no such thing as a ‘ beer belly’. Alcohol per se doesn’t make you fat. It’s what you have with the alcohol that does this. Second, alcohol is regarded as a toxin, and as such is thought to be metabolised by the body for energy, lost as heat or used as a fuel of first priority. Research has shown that alcohol, like carbohydrate, seems to take precedence in the energy system before fats. Finally, research substituting alcohol energy for other nutrients (such as carbohydrates or fats) has generally shown a smaller increase in body weight over time, which supports the notion that alcohol is generally used up as energy rather than stored as fat. However, if alcohol is combined with fatty foods, it will be used as energy while the fats will be stored in the fat cells. So it’s probably not the alcohol that causes weight gains: it’s the chips, peanuts and other fatty foods in the diet. If you cut out the fats, you will be more likely to lose those extra kilograms—even without cutting out the alcohol. 76
Professor Trim's - pages 24/8/06 10:00 Page 77
NUTRITION NEWS
INCREASE VARIETY Eat a wide variety of foods If you eat from only a small variety of fatty foods every day, it’s easy to get fat. This was observed in a comparison of eating habits between lean and obese people in Nevada. The obese people ate from fewer food types than the lean people, and ones that were generally higher in fat. In a previous study, low scores on an index of food variety were found to be associated with almost all the established cardiovascular risk factors such as cholesterol, high blood pressure and high blood sugars. A chronic intake of fat is the best way to keep or increase fat on the body. To combat this, even without focusing directly on dietary fat, simply increasing your selection of foods is a wise move. The first of most government dietary guidelines usually states that we should ‘. . . enjoy a wide variety of nutritious foods’. These include breads, cereals (breakfast cereals, pasta, rice), vegetables, legumes, meats, chicken, fish, eggs, nuts, milk, cheese and yoghurt.
Go for something unfamiliar Diet-induced thermogenesis is the term given to energy used up (and given off as heat) following the digestion of food. This is known to account for a significant proportion of daily energy use (around 15–20%). Hence, any increase in thermogenesis can be beneficial for fat loss. One way of increasing thermogenesis was hinted at in European research on thermogenesis in a group of women fed familiar and unfamiliar foods.92 Diet-induced thermogenesis during the first serving of a meal consisting of unfamiliar food was found to be significantly higher than when familiar foods were eaten. Familiarity, in metabolic terms, it seems, might breed content. Try some unfamiliar foods to make your body work harder.
Add a little spice to your food The idea that spicy foods might entail some benefits in fat loss was first put to the test by scientists in 1985. In an experiment using a variety of different spicy foods, it was found that metabolic rate was increased with the addition of spices to food, resulting in an increase in energy use over a 24-hour period. Naturally, this generated a lot of interest in the weight-control industry. But for many years, the results couldn’t be replicated. Research carried out at the University of Tasmania in the early 1990s, however, might put the 77
Professor Trim's - pages 24/8/06 10:00 Page 78
BECOMING SLIMMER
idea squarely back on the waist watchers’ table. Dr Eric Colquhoun and his colleagues found that:93 • •
different foods have different levels of the spicy ingredients associated with metabolic increases there has to be a prolonged use of the right type of spice in order to derive any metabolic benefits.
According to Dr Colquhoun, one ingredient in spices such as peppers and chillies could be responsible for most of the fat-burning effect. The ingredient is called ‘capsaicin’. The Tasmanian group found that if capsaicin was injected into the blood in a rat’s hind limb, oxygen consumption was increased to the large muscles, meaning an increase in energy being used and, ultimately, therefore a decrease in body fat. However, the Tasmanian researchers also found that the amount of capsaicin ranged from around 47% in Tabasco sauce to around 5% in other types of chilli sauces. Therefore it’s difficult to make a general claim about the benefits of spices without knowing their natural constituents. Colquhoun’s group also found that oxygen consumption in rat tissue didn’t increase for some days after the introduction of spicy foods into the bloodstream, but when it was introduced, it led to a gradual increase in metabolism. This research has reignited the issue of spicy foods and weight control. A metabolic boost should be seen as a possible bonus, and spicy flavours can improve the taste of low-fat food. If you find you’re complaining of dietary blandness, spice up your meals with some of the ‘hot stuff ’.
Make the most of caf feine It’s well known that caffeine, as in coffee, can have a stimulatory effect on many people. Many studies have now shown that this translates into thermogenesis: it can help raise the metabolic rate. Some studies show an increase in metabolism of 7–22% in lean people, according to the amount of coffee consumed. There’s also evidence that caffeine increases fat burning and helps ‘spare’ carbohydrate to be used as a fuel. For this reason it’s consumed by endurance athletes in long-distance events. Therefore moderate coffee consumption (3 to 4 cups daily) has been promoted as an aid for those wanting to lose extra body fat. Research from Switzerland suggests, however, that the effect of caffeine might not be as great in those who most need to reduce fat.94 When measuring the metabolic rate of lean and obese people in a metabolic chamber 78
Professor Trim's - pages 24/8/06 10:00 Page 79
NUTRITION NEWS
over 24 hours, researchers found that the effects of caffeine were blunted in people regarded as obese. Although there was still some effect, it tended to diminish as the level of body fat rose. The researchers suggest that for various physiological reasons, obesity decreases the body’s ability to metabolise caffeine, resulting in a less significant effect for the obese. There might still be a small effect, though, and this can at least justify not cutting caffeine out of your eating plan.
Graze, don’t gorge If you eat a given type and amount of food in a day, does it really matter how or when you actually eat it? It appears that it does. A ‘grazing’ pattern of eating with smaller meals eaten more often might in fact be better than a gorging pattern with only one to two large meals and little else each day. Eating more frequently might help minimise hunger levels during the day and therefore help you to consume less total energy. Researchers at Laval University in Canada studied the effect on metabolism of food consumed in one large meal (653 kcal or 2743 kJ) compared with four small meals (163 kcal or 685 kJ each) at 40-minute intervals.95 There was a larger overall increase in metabolic rate after eating with the four smaller meals than with the single large meal. Fat utilisation for body fuel was also greater with the four-meal pattern. Eating more often can also help minimise hunger levels during the day, and therefore help you to eat less overall. If you’ve just had breakfast and you plan to eat nothing until dinner time, you might not get there before the ‘bear in your belly’ gets the better of you. For these reasons as well, it’s better to ‘graze’ rather than ‘gorge’.
Eat for health and weight control The motivation for many people to eat better is to lose weight. But efforts to do so by cutting back on fat, for example, aren’t entirely without hazard, as was revealed in a 1990 study of the dietary habits of over 3000 Australians.96 Researchers separated the group into high- and low-fat consumers. Those on the lower fat intakes achieved this by restricting meats and dairy products, and this resulted in a reduced intake of vitamins A and B12 and the mineral zinc. The poor reputation of meats and dairy foods with slimmers means that they’re often seen as fatty and are cut back unnecessarily or eliminated from the diet altogether. This is a dangerous trend, which has sparked health 79
Professor Trim's - pages 24/8/06 10:00 Page 80
BECOMING SLIMMER
campaigns to inform consumers about the benefits of leaner varieties of meats (lean beef, trim lamb and pork) and lower fat milks and cheeses. The Australian researchers concluded that ‘. . . for optimal effect, nutrition messages about specific nutrients should not be given in isolation but in the context of a general “healthy eating” message’. This makes perfect sense. If you’ve developed a fat phobia, try to regain a more healthy perspective.
OTHER MEASURES Don’t bother with food combining The notion of combining or, more correctly, not combining certain foods has a long history. First proposed in the 1920s by a medical graduate, the typical claim is that the human body doesn’t possess enough of the enzymes required to digest both protein and carbohydrate at the same time. Eating these together would therefore overload the system. If this biochemical claim were true (and it isn’t) it would be an advantage for fat loss, as some food would remain undigested and pass through the body without the energy being absorbed. But the human body is perfectly capable of dealing with any nutrients, be they protein, carbohydrate, fat or alcohol, all at the same time. If it wasn’t, human beings wouldn’t have evolved as far as they have. If you are tempted to succumb to this argument, remember that the body has enzymes specifically for each nutrient. The enzyme pepsin works on protein, while a whole team of sugar enzymes go to work on carbohydrate. Diets that promote an enzymatic benefit from separating nutrients or foods are clearly misguided.97
Avoid the dangers of fad diets In case we don’t already know it, a survey of 19 popular diets from women’s magazines reported in the Australian Journal of Nutrition and Dietetics has found that none conforms to both the national guidelines for nutritional health and the recommended dietary targets.98 The survey also showed that: • • •
80
most popular diets contain an appropriate amount of energy from fat, but about half provide too little energy from carbohydrate recommended fibre intake is too low in about one-third of commercial diets iron intake was less than 70% of the recommended daily intake in up to half the diets
Professor Trim's - pages 24/8/06 10:00 Page 81
NUTRITION NEWS
•
nearly half the diets included no cereals, vegetables or dairy foods on some days, often limiting intake to fruit only.
When determining the suitability of a proposed diet, you need to consider its overall health benefits—not just whether or not you will lose weight. The 19 diets surveyed might have helped women lose weight, but this is most likely to be short term, and to have this as a priority at the expense of your general health is sheer stupidity.
Get smar t with ar tificial sweeteners The advent of artificial sweeteners was supposed to be a boon to those watching their waistline. But claims in the popular media that these might increase appetite and therefore food consumption have led some consumers to question their usefulness for reducing energy intake. To investigate these claims, Dr Adam Drewnowski, a renowned expert in the field from the University of Michigan, has reviewed all the research in the area.99 He concludes ‘. . . there is no evidence that the addition of an intense sweetener to a plain stimulus promotes appetite or results in increased food consumption during some later meal’. Drewnowski’s analysis is an eye-opener about how misinformation in the health area is spread. Most claims that intense sweeteners promote hunger and increase food consumption have been based largely on two pieces of published research. The first, a letter to the Lancet, claimed that the use of aspartame (a commonly used sweetener) increased the motivation to eat. The second report, from a reputable laboratory in the UK, claimed to show an increase in food consumption later in the day after sweetener use. Although this was widely reported, subsequent research failed to replicate the results. Drewnowski’s conclusion, based on a careful review of all this research, is that hunger is more affected by the type and volume of food eaten than by the sweetness or energy density of the food. Sweeteners do not appear to influence appetite or food consumption. There’s also the question of whether sweeteners actually help fat loss. Using artificially sweetened foods does appear to be more effective for this than sweetening products with sugar. But, again, few long-term studies have compared ‘sweetened’ foods in an eating plan with non-sweetened alternatives. One such study, reported in the journal Appetite in 1988 did show that people using sweeteners experienced better long-term maintenance of weight loss.
81
Professor Trim's - pages 24/8/06 10:00 Page 82
BECOMING SLIMMER
Outsmar t the cravings The way to a man’s heart, it’s said, is through his stomach. But if you’re thinking of doing it with chocolate, think again. A good hunk of steak might do the trick better. Research on food cravings is now beginning to uncover why a man feels he must have a steak, when all a woman wants is chocolate. Cravings, for people eating normally, it seems, are not based on nutritional needs, but are probably hormonal or psychological in origin. How else can we explain that young, pre-menopausal women crave fat, sugar and carbohydrates, whereas post-menopausal women, whose female hormonal status has changed, have cravings more akin to a man’s? According to Dr Harvey Weingarten, of McMaster University in Canada, 97% of young women he sampled in a large study on food cravings claim to have unexplained midnight urges for particular foods. This occurred in only 67% of men. These findings are discussed in a book called Why Women Need Chocolate, by dietitian Debra Waterhouse.100 She claims that men crave meat because they need protein for muscle. Although studies have yet to prove this idea, there is sound evidence to support the notion that the food cravings of men and women are different. Dr Andrew Drewnowski, an expert in taste preferences, has shown that many foods high on the female preference list are a mixture of fat and sugar. He suggests, ‘Although food cravings undoubtedly exist, the nutrientspecific term “carbohydrate craving” may be a misnomer, indicating sensory preferences for foods that are sweet, rich in fat, or both’. Overwhelmingly, sweet cravings should be satisfied by something sweet, but not fatty. Having jelly babies instead of chocolate might not always work, but when you’re done eating jelly babies, you haven’t eaten any fat. Savoury cravings might need to be satisfied by that ‘meaty’ flavour—just make sure it’s lean.
Learn label lingo The 2002 supermarket contains thousands of foods with an assortment of nutritional claims. This can leave even the keenest shopper bewildered. A Choice Magazine survey of 408 shoppers in New South Wales, for example, found that many people were not aware of what common nutritional claims actually meant. Here’s a summary of what the survey revealed:101 ‘Reduced’, ‘lower’, ‘less’: More than 50% regarded it as an absolute term (e.g. reduced-fat cheese has the same fat content as reduced-fat yogurt). People confused these terms with ‘low fat’. 82
Professor Trim's - pages 24/8/06 10:00 Page 83
NUTRITION NEWS
‘Light’ and ‘lite’: Over half thought yoghurts labelled ‘light’ or ‘lite’ had a lower or low-fat content—and they were right. But 33% believed oils so labelled were low or lower in fat. ‘% fat-free’: Some thought that a 97% fat-free frozen dessert was completely fat-free. Others thought that a 90% fat-free mayonnaise was low in fat (but not at 10% fat). Almost half surveyed thought that 80% fat-free mince was lower in fat than lean mince—incorrect. ‘Fights cholesterol’ and ‘cholesterol free’: Almost one-third thought that the ‘fight cholesterol’ claim on a margarine meant lower or low food cholesterol, and they were correct. However, one in ten thought the margarine was low in fat or fat free. ‘No added sugar’: About half thought products labelled ‘no added sugar’ contained little or no sugar. But these claims are often found on products fairly high in natural sugars, such as fruit juice and jam. In response, Food Standards Australia & New Zealand (FSANZ) has produced a Food Standards code which was due to be released at the time of writing. For definitions of labels on foods and their meaning check www.foodstandards.gov.au.
83
Professor Trim's - pages 24/8/06 10:00 Page 84
Chapter 6 MOVING AND LOSING
INTRODUCTION Ask anybody how to lose weight and they’ll invariably answer: diet and exercise. We’ve seen in the previous chapters that the typical diet can be downright counterproductive. It might interest you to know that the usual approach to exercise is probably wrong too. The standard idea about exercise is that you keep going until it hurts: the ‘no pain, no gain’ philosophy. Yet physiological research shows that this is not only incorrect; it might also be dangerous. Anyone carrying excess poundage is also likely to be a little unfit. Doing vigorous exercise when you’re unfit can put extra pressure on your cardiovascular system and even bring on a heart attack. What is more important, high-intensity exercise doesn’t burn fat; it uses that other main energy source from carbohydrate—glucose. In someone who’s not very fit, ‘high intensity’ is not very high. So any form of activity that’s painful—or even somewhat uncomfortable—is not likely to use up excess body fat optimally in a fat person, even though it might do so in someone who is very fit. This means that exercise doesn’t have to be, and indeed shouldn’t be, very vigorous for fat loss. In fact, the most that’s needed from you is to move. Because of advances in technology and effort-saving devices in modern society, nobody does much of this any more. And it’s this ‘incidental’ movement that can add to the energy burned up in the course of a normal day. There are a number of simple ways you can accomplish this.
ACTIVITY LEVELS UP = WEIGHT DOWN? For some people, weight loss is difficult, even if they adopt the correct lifestyle changes. Expectations are often high. In fact, surveys have shown 84
Professor Trim's - pages 24/8/06 10:00 Page 85
MOVING AND LOSING
that overweight individuals expect to lose an average of 35% of their body mass on a weight-loss program, whereas a 5–10% loss is a more common average and a more realistic goal. Epidemiological studies have shown, however, that losses of 5–10% are enough to lead to significant improvements in metabolic health, including lowered blood pressure, lowered blood sugars and altered blood fats.102 Improvements in metabolic health result particularly from changes in physical activity levels, although improvements in diet will also help achieve them. Exercise, helping, as it does, to reduce blood sugars by using them up in the muscles, leads to an improvement in insulin resistance— and poor insulin resistance is the underlying cause of many metabolic health problems. Therefore, health gains, as much as weight loss, should be seen as the goal of any weight-loss program. Health gains, as much as weight loss, should be seen as the goal of any weight-loss program.
DON’T GET STRESSED ABOUT GETTING ‘FIT’ Exercise has connotations of good health. But the increased prevalence of obesity in recent years has concentrated attention more on whether reductions in body fat, rather than exercise per se, might be a better goal for the average person. What is more, as we age there’s a natural tendency to get fatter. Is it important to fight this, or should we simply carry out some light activity daily? Research carried out with middle-aged and older men at the University of Maryland compared the benefits of aerobic exercise and weight loss in reducing risk of heart disease.103 Men aged 61 and older were given either a regular exercise program on cycles and treadmills three times a week or instruction on how to cut down food intake. Results were compared with a control group, who maintained their weight over the nine months of the program. Surprisingly, while those in the weightloss group lost about 10% of their body weight, they didn’t increase their fitness levels. Still, there was an improvement in blood pressure, blood fats and blood sugars. For those in the exercise only group, there was an improvement in fitness, no loss in weight and also relatively little change in risk factors. The researchers concluded that, at least in middle-aged men, weight loss is more important than fitness when it comes to the overall health of the body. It’s reasonable to assume that this particular finding would also apply 85
Professor Trim's - pages 24/8/06 10:00 Page 86
BECOMING SLIMMER
to women. So, don’t assume that exercise alone will help you lose weight and gain health—it won’t.
INCREASE YOUR ‘INCIDENTAL’ ACTIVITY Captain Cook didn’t need an aerobics instructor on board the Endeavour. And neither would we if we had to do what our forebears did just to stay alive: chop the wood, catch kangaroos, wash the clothes by hand, and so forth. Not having to do any of this has meant decreased energy use in modern times, estimated at around 1000 kcals (4200 kJ) a day (see Chapter 4), or the equivalent of 1 kg of fat every seven days! Captain Cook didn’t need an aerobics instructor on board the Endeavour. And neither would we if we had to do what our forebears did just to stay alive. How do you catch a kangaroo today? You can’t (unless you want animal rights lobbyists on your doorstep). But you can walk instead of driving the car, take the stairs instead of escalators, not use technology where person power can do the job, or simply stand when you could sit. All of this ‘incidental’ movement—and much more—can help burn the fat that’s not being burned at the moment because of the use of machines. Think incidental activity, and you will need to worry less about exercise.
JUST MOVE MORE . . . DAILY Recommendations for improving physical fitness over the past two decades have involved carrying out intensive activity for 20–30 minutes on three to four days of the week. Until recently, this was also the prescription given for losing fat, on the understanding that exercise for fitness is no different from exercise for slimness. More recently, it’s been found that the only type of effort really needed to reduce fat is movement.104 Regular movement, either through walking, running, cycling, rowing or playing games, is required on as many days of the week as possible—preferably seven days. Fortunately, this movement doesn’t need to be as vigorous as the type of activity needed for improvements in aerobic fitness. 86
Professor Trim's - pages 24/8/06 10:00 Page 87
MOVING AND LOSING
IF YOU’RE TOO BIG TO MOVE COMFORTABLY— FIDGET! For some people, large movements, such as carrying one’s own body weight, are painful or difficult to execute. This might be because of the excess weight they are carrying, or as a result of injury. In these cases, the energy used up by fidgeting can far exceed that used up by simply sitting. Researchers in the US, for example, have shown that fidgeting can add to the energy costs of your resting metabolic rate or those of just sitting or standing,105 as shown in Table 6.1. Table 6.1 Extra energy costs of fidgeting Energy costs (kcals [kJ] per hour) Resting Metabolic Rate Extra energy costs (add to 60 kcals/h) Sitting motionless Fidgeting while seated Standing motionless Fidgeting while standing
60
3 + 5 kcals (13 + 21 kJ/hr) hr 40 + 21 kcals (168 + 88 kJ/hr) hr 10 + 7 kcals (42 + 29 kJ/hr) hr 70 + 29 kcals (294 + 122 kJ/hr) hr
BEWARE THE M AND M (AND M) SYNDROME It’s well known that being overweight can cause metabolic (ill-health) problems. What is less well known is that being overweight can also cause mechanical problems, such as a sore back, knees, hips or ankles, asthma or difficulty in breathing, tiredness and even incontinence. These problems can in turn affect motivation (the third ‘M’),106 which results in a drop in physical activity and a cyclical problem with obesity, as shown in Figure 6.1. In many cases, reducing the weight reduces the resultant mechanical problems. This is best done through a sensible eating and exercise program. So persisting with an activity program or finding exercises that are less ‘painful’, such as walking in water, riding a bicycle or other weightsupporting activities, is perhaps the best approach. If pain or discomfort persists, consult a doctor, podiatrist or exercise specialist. 87
Professor Trim's - pages 24/8/06 10:00 Page 88
BECOMING SLIMMER
Figure 6.1 A cycle of weight problems Increased body weight
Inactivity
D
re ec
as
ed
Joint problems
m
iv ot
at
ion
Inc
re
as
ed
pa
in
Respiratory problems
DON’T SIT WHILE YOU CAN STAND The decline in incidental activity in modern western life has significantly reduced our daily energy expenditure. While a return to pre-industrial revolution times is unlikely, adding certain activities to your daily living can help compensate for the decline in overall energy expenditure.107 For example: • • • • • • • • • • 88
don’t sit when you can stand don’t drive or ride when you can walk don’t use remote controls for TVs, stereos, garage doors, etc. do it yourself, don’t ask someone else (the kids) to do it for you mow the lawn and wash the dishes by hand carry your bags, don’t use a trolley walk up stairs, don’t use the lift park some distance from your destination and walk walk, don’t drive, locally hang out the laundry; don’t use a clothes drier (unless it’s raining).
Professor Trim's - pages 24/8/06 10:00 Page 89
MOVING AND LOSING
ADD MORE ACTIVITY TO YOUR LIFESTYLE In line with recent research, which shows clearly that total, accumulated activity is more important for weight loss than intense, continuous activity, several studies demonstrate that this is best achieved by building activity into one’s lifestyle. Dr Steven Blair and his colleagues from the Cooper Aerobics Institute in Dallas, Texas108 have found that if individuals are asked to carry out a set amount of planned exercise during the day, they tend to do less incidental activity for the rest of the day. This is particularly so with increasing age. Building activity into one’s lifestyle by becoming more active throughout the whole day is likely to be more effective for long-term weight loss.
DO SMALL, REGULAR BOUTS OF PHYSICAL ACTIVITY Work with athletes has led scientists to believe that exercise needs to be carried out in a single session for the most benefit. And while this might be true for anyone wanting to increase their fitness levels, it’s now thought that it is not necessary for reducing fatness. Frequent short bouts of movement appear to be a better recommendation for long-term weight loss than fewer, more extended bouts. Research with obese women carried out at the University of Pittsburgh compared the effects on subjects walking for four bouts of 10 minutes a day over three months with those on others walking for one session of 40 minutes a day at the same intensity.109 The results showed that because the group carrying out the short bursts complied much more readily with the program, they tended to lose as much or more body weight over the test period. Perhaps unexpectedly, they also had a slightly better improvement in cardiovascular fitness. The results are almost certainly explainable by the fact that it’s easier for big people to comply with a program of shorter exercise sessions. Frequent short bouts of movement therefore appear to be a better recommendation for long-term weight loss than fewer, more extended bouts.
89
Professor Trim's - pages 24/8/06 10:00 Page 90
BECOMING SLIMMER
VOLUME OF EXERCISE, NOT INTENSITY When it comes to exercise or physical activity: Volume = Frequency Intensity Duration We now know that it is total volume of activity that is most relevant for weight loss. This can be increased by increasing any of the components: frequency, intensity or duration. However, in someone who is overweight and unfit, high-intensity exercise can be dangerous. Therefore, increases in frequency and/or duration are usually the preferred options.110
IF YOU’RE AEROBICALLY FIT . . . Aerobic capacity is the ability of the heart and lungs to carry oxygen to working muscles. In very big people who are out of condition, aerobic capacity (sometimes referred to as ‘fitness’) is low. With increasing levels of activity, even at low levels of intensity, aerobic capacity increases so that more intense activity can be carried out at a similar comfort level. Hence it becomes possible for someone who is fit (but perhaps still overweight) to reduce the duration and frequency of activity and achieve economies of time by increasing exercise intensity.111 Do take care, though, not to reduce your activity levels for the rest of the day as a result of fatigue from vigorous activity, thereby counteracting the benefits of the shorter, but more intense activity.
DON’T EXPECT SHORT BOUTS OF ACTIVITY TO KEEP YOU SLIM One of the main causes of the modern obesity epidemic is the lower ‘ambient’ level of activity required in the modern environment. Studies reported elsewhere in this book (see Chapter 4) have shown that over the last century or so our activity levels have probably decreased by up to 1000 kcals (4200 kJ) per day. This shortfall is unlikely to be made up by increases in activity through short exercise sessions, particularly where these are compensated for by decreases in total daily activity. Large and permanent losses in body weight can only come from a significant commitment to being more active every day, probably for up to 80 minutes or so (although not necessarily continuously). 90
Professor Trim's - pages 24/8/06 10:00 Page 91
MOVING AND LOSING
A 2002 consensus statement on exercise and weight control from a World Health Organisation meeting in Bangkok112 supports this by suggesting that: The current physical activity guideline for adults of 30 minutes of moderate intensity activity daily, preferably all days of the week, is of importance for limiting health risks for a number of chronic diseases including coronary heart disease and diabetes. However for preventing weight gain or regain this guideline is likely to be insufficient for many individuals in the current environment. There is compelling evidence that prevention of weight regain in formerly obese individuals requires 60 to 90 minutes of moderate intensity activity or lesser amounts of vigorous intensity activity. Although definitive data are lacking, it seems likely that moderate intensity activity of approximately 45 to 60 minutes per day, or 1.7 PAL (Physical Activity Level), is required to prevent the transition to overweight or obesity. For children, even more activity time is recommended. A good approach for many individuals to obtain the recommended level of physical activity is to reduce sedentary behavior by incorporating more incidental and leisure-time activity into the daily routine. Political action is imperative to effect physical and social environmental changes to enable and encourage physical activity. Settings in which these environmental changes can be implemented include the urban and transportation infrastructure, schools, and workplaces.
DON’T OVERESTIMATE THE ROLE OF FITNESS EXERCISE The scientific evidence supporting the need for exercise in weight loss— particularly in very big people—is surprisingly equivocal. This could be because the net value of exercise has been overestimated, say US exercise specialists Glen and Arlene Blix.113 Most estimates of the value of exercise are based on the amount of energy burned up during the exercise. Jogging a mile (1.6 km), for example, will burn around 95 kcals or 400 kJ. If 1 kg of fat is the equivalent of 7619 kcals or 32 000 kJ, this means an extra mile a day would burn up 1 kg of fat in about five weeks. But as the Blixes point out, this ignores the fact that if someone isn’t jogging, they’re doing something else. Even lying in bed requires energy. Therefore it’s the net energy used during exercise that should be considered, rather than the gross expenditure. If the alternative to jogging was walking 91
Professor Trim's - pages 24/8/06 10:00 Page 92
BECOMING SLIMMER
around the house, about 48 kcals or 200 kJ might be burned in the same period. So it would now take closer to 7.5 weeks to burn the extra kilogram of fat, which is a much less rosy proposition. In addition to this, the amount of energy used up during exercise decreases with the amount of weight lost. Theoretically, then, any loss in weight from exercise will tend to slow down the rate of weight loss that occurs from a similar amount of exercise in the future. In fact, the Blixes calculate that even if you walked 1000 miles (1600 km), you’d only lose 3.53 lbs (1.6 kg) of fat, rather than the 33 lbs (15 kg) predicted by other equations! While none of this discounts the value of regular exercise for fat loss, it does rather scotch the idea that a 30-minute aerobics class three times a week is the answer to your weight-control problems. Regular, daily, planned and incidental exercise needs to be built into our lifestyle for long-term weight control.
GO FOR DISTANCE, NOT SPEED A legacy of the fitness tradition is that effort is important. The faster and harder an exercise is carried out, the greater the improvement in fitness. But as we’ve said, reducing fatness is different from increasing fitness. Body fat responds to total energy use. In a relatively fat, unfit person, intensive activity can result in blood sugars, rather than fats, being used as the fuel source. Setting a distance rather than a speed is therefore likely to be more productive for fat loss, in contrast with fitness.115 Walking a daily distance of 3–4 km is generally accepted as appropriate for most people. This can be carried out at a leisurely pace, or even done in three to four bouts of 1 kilometre. The main thing is to make sure that it’s done. An equivalent distance for cycling is around 15–20 km. You’ll need to work out your own equivalents for other activities such as rowing or skiing.
LONG AND SLOW DOES THE JOB You might have always wanted to run a marathon but been turned off by all the heavy training involved. You might be prepared to give your ‘eye teeth’ to be fit and healthy, but can’t stand the thought of getting out of breath. The good news is that all these things might be possible—without going to extremes—as has been shown with novice marathon runners at the 92
Professor Trim's - pages 24/8/06 10:00 Page 93
MOVING AND LOSING
University of Northern Iowa.116 A total of 28 healthy males and 41 healthy females were trained (at the same intensity) either over four days a week or six days a week for 15 weeks before completing a marathon. Surprisingly, those who were trained for only four days a week were able to complete the event as quickly as those who trained six days a week. They also lost as much body fat and recorded similar other improvements in markers of fitness, suggesting that, at least in novices, a high level of intense training is not necessary. This training was, moreover, only moderate in intensity (60–75% of maximum), suggesting that benefits in terms of fat loss and fitness can be gained at a lower intensity than is often recommended.
ONLY DO PLANNED EXERCISE THAT YOU ENJOY It’s important for weight control that you be able to maintain any planned exercise program for a lifetime.117 By definition, you are only likely to exercise if it’s enjoyable. And while you perhaps cannot expect to enjoy it from Day 1, you should know after a number of sessions whether or not you are likely to continue with a particular form of exercise. As movement, and not any specific type of exercise, is the key to longterm success, a regular, planned exercise program should include the activities you enjoy.
ENJOY VARIETY IN EXERCISE To succeed in losing weight, you must carry out planned exercise over your lifetime. One of the main impediments to doing so for many people is the boredom, or staleness, that can set in. Try several different types: walking, cycling, rowing, weight training. This can help you make up your mind about what you prefer. You can vary your activity from day to day to derive maximum enjoyment.118 Varying the exercise routine—type, duration, location, time of day—not only increases your prospects of enjoyment, but enhances your prospects of fat burning through change. Changing the routine prevents the body adapting to one particular form of activity and becoming too efficient at performing it. If this occurs, less energy, and therefore less fat, is used up carrying out the activity. While specificity (or carrying out the same activity regularly) is vital for athletes who are competing in a specific event, it’s not necessary for 93
Professor Trim's - pages 24/8/06 10:00 Page 94
BECOMING SLIMMER
fat loss. The main concern for the latter goal is regular use of energy— any energy used in any way!
KEEPING WEIGHT OFF ONCE YOU’VE LOST IT Exercise is more important in weight maintenance than in the early stages of weight loss. Research has shown that in the long term, a lifestyle program with exercise built into it is much more likely to be effective.119 It helps burn energy (if done the right way). But it might even help change eating patterns. Men, in particular, have been shown to eat more carbohydrate and less fat as a result of a regular, planned exercise program. Relapse is also less common in women who have exercise as part of a regular maintenance routine. . . . in the long term, a lifestyle program with exercise built into it is much more likely to be effective. If you are a big person, the changes that are likely to have the greatest impact early in a fat-loss program are changes in food type (such as a decrease in fat) combined with increases in incidental activity. Building in more planned activity into an ongoing program will help stop you relapsing into old habits and regaining weight.
WEIGHT TRAINING—FOR THE NOT SO FAT There’s controversy in the scientific literature about the use of weight training in fat loss. In theory, doing weights can help you maintain lean body (muscle) mass and therefore a good metabolic rate, even while your body is losing fat. This would also assist with further decreasing body fat.120 If you are obese or very overweight you might find that you are more concerned about your total body size than your muscle-to-fat ratio. You might also find it embarrassing and uncomfortable to lift weights. Therefore, your time is probably more efficiently spent doing more aerobic-type activity, such as walking. For someone who doesn’t have a lot of fat to lose, however, weight training can help maintain muscle, which might otherwise be lost through food restriction. The most effective form of weight training for this purpose is circuit training, or the use of relatively light weights and high repetitions (15–20 reps). 94
Professor Trim's - pages 24/8/06 10:00 Page 95
MOVING AND LOSING
ONE FOR THE VERY FIT Some extra-active people have difficulty losing that extra kilo of fat they have gained despite their high energy output. Why is this? And what can be done? The question has been partially answered by a study from the University of Limberg in the Netherlands121 that looked at the metabolism of fat in athletes who have overtrained and who are given a fat as well as a carbohydrate supplement. The researchers found that depleting the body’s carbohydrate stores—the opposite of carbohydrate loading used by marathon runners—might decrease body fat, depending on the individual’s nutrient state at the time. The scientists reduced the glucose stores of one group of men by making them cycle for two-minute bursts over 90 minutes the night before a test run of cycling at 50% of their maximum effort for 90 minutes. On another occasion, the group was fed a high-carbohydrate diet the night before the test, with no exercise to reduce the fuel source. Fat use during exercise was highest for those who were carbohydrate depleted. The theory behind this is that fat will be used more as an energy source if there is scant carbohydrate (and thus sugar) in the system. While the theory appears to have worked in practice in the Dutch research, the potential dangers of this approach preclude its use, except under strict supervision and possibly only as a last resort for elite athletes.
DON’T EXERCISE TO THE POINT OF BREATHLESSNESS The body uses two main sources of energy or fuel. The first of these, glucose or blood sugars, comes from the carbohydrates in food. The second, fat, comes mainly from fat in the fat cells of the body, which themselves come from fat in food. Glucose is the main type of fuel used by the body for vigorous intensive activity; fat is used more in long-duration, low–moderate intensity activity. Therefore, as one’s activity changes from a sprint to a leisurely stroll, the body shifts from burning its limited supplies of glucose to burning its large supplies of fat. Some fitness experts argue that because more total energy is used up at a high intensity, more fat will still be burned, even though the proportion of fat used as a fuel decreases. However, while this might well be true for fit people, it’s much less likely to be true for fat people, who are usually less fit and therefore burn less fat than fit people even at a higher level of exercise intensity. 95
Professor Trim's - pages 24/8/06 10:00 Page 96
BECOMING SLIMMER
The general principle therefore is that low–moderate intensity activity is best for optimal fat loss in most fat and unfit people.122 If your activity is intense enough to make you breathe very heavily or leave you short of breath, it’s likely to be using up less fat as an energy source.
DON’T DRESS TOO WARMLY WHEN YOU EXERCISE For some time now, scientists have claimed that heat treatments for fat loss (in contrast with weight loss) don’t work. If anything, they might increase weight by decreasing metabolic rate. In fact, it might be cold conditions that burn fat best. Research by Canadian scientists on soldiers in the Arctic has shown that even with a large increase in food intake, body fat is kept down by cold temperatures.123 The simple explanation for this is that the body uses up energy in the cold to maintain body heat. You might think that the difference between a cold and a hot day is insignificant. But research carried out at New England University in New South Wales has shown that a temperature difference as small as 5oC can lead to an average 10% increase in the body’s metabolic rate in people wearing light clothes. This can amount to the equivalent of a large glass of beer in a day, or around about 5 kg of fat loss in a year. So how realistic is the use of cold for fat loss? While nobody is recommending freezers instead of sauna baths in gymnasiums for weight loss (yet), there are indications that they would actually work better. In the meantime, some tips for the waist watcher are: • • • • • •
avoid overheating by not overdressing in winter avoid overheated buildings or vehicles wear clothes that allow the body to ‘breathe’, such as cotton, rather than synthetics avoid heat treatments such as saunas and steam baths exercise during the cooler hours of the day (e.g. early mornings) avoid overheating at night under a doona that’s too warm.
DIGITAL PEDOMETERS Advances in digital pedometers have made these a useful tool in any weight loss or exercise program for giving an indication of the amount of energy used up in the course of a day.124 Some new pedometers not only measure 96
Professor Trim's - pages 24/8/06 10:00 Page 97
MOVING AND LOSING
distance covered—they even estimate calories consumed. One version can even sense and measure forms of movement that don’t involve ambulation, such as rowing or cycling. A problem that remains with some pedometers is varying stride length, such as occurs in walking up and down hills or between warming up and more extended jogging. But this can be overcome by using different stride lengths, which can easily be put into the device according to the terrain, type of stride, and so forth. Because they can be worn all day, the new pedometers give you a good indication of day-to-day variations in your activity. If you’re over or under your daily average, you can compensate by doing other activities or cutting back on high-energy foods.
WHEN YOU START TO LOSE Your body adapts to stressors you place on it. Exercise is a form of physical stressor, and physiological adaptation occurs in response to any form of constant regular exercise.125 This means that although you might continue to get health benefits and maintain a set body weight by carrying out a certain amount of exercise, you might no longer continue to lose weight or, more importantly, fat. . . . making the body less efficient is going to use more energy. Ironically, making the body less efficient will induce it to use more energy. So increasing the frequency, intensity, time or type of your exercise is likely to be less beneficial if your body has become efficient at it.
SWIMMING NOT THE BEST ACTIVITY FOR WEIGHT LOSS Swimming is usually one of the first exercises recommended for unfitness or fatness. But while swimming might be fine (if done properly) for fitness and general all-round wellbeing, it’s not an effective exercise for weight control compared with other weight-bearing activities.126 There are a number of reasons for this: 1. Since your body weight is supported in water, less overall energy is generally required to move at a set level of intensity in water. 97
Professor Trim's - pages 24/8/06 10:00 Page 98
BECOMING SLIMMER
2. Because fat floats, the fatter you are, the less energy you need to stay afloat and move in water. 3. The rate of energy expenditure in water is totally dependent on the efficiency of the swimmer. A very poor swimmer will burn more fat than a very good one. 4. Maintenance of core body temperature is much easier during and after swimming than during and after land-based activities. Therefore no energy is required to return the body to its core temperature. 5. A lower centre of gravity and a greater proportion of body fat in females helps them float better and therefore use less energy than men in the water. Hence, swimming is an even less effective exercise for fat loss in women than it’s likely to be in men. . . . swimming might be fine for fitness and general all-round wellbeing, but it’s not an effective exercise for weight control. All of the above doesn’t deny the benefits of swimming, and particularly the more vigorous forms of aquarobics. However, relative to other weightbearing exercises such as walking, swimming’s principal benefits will be fitness gains for high-intensity activity rather than fat loss. If you are very big, and find weight-supporting activities difficult, swimming and other aquatic activity, including walking in water, can be a good, less painful introduction to an activity program. But remember, you will need to carry out some other activity eventually to really work on your weight loss.
AIM FOR THE PSYCHOLOGICAL REWARDS OF EXERCISE For someone who’s out of condition, any level of exercise can be uncomfortable. However, with increased fitness, exercise can become its own reward.127 And while fitness is not necessarily the goal of an exercise program for weight loss, fitness will result from even mild, regular exercise. There are three stages between unfitness and fitness: Stage 1. The discomfort stage is marked by easily getting out of breath, tiring quickly and not looking forward to any form of effort. It might last for days, weeks or even months. The type of motivation required to get through this stage is extrinsic, external to the individual. 98
Professor Trim's - pages 24/8/06 10:00 Page 99
MOVING AND LOSING
Stage 2. The physical stage is marked by feelings of wellbeing after finishing exercising. The rewards are physical and tend to become more intrinsic as well as extrinsic. This means that the exercise in itself begins to produce a level of enjoyment leading to satisfaction. Stage 3. The psychological stage: For many people, a third stage of fitness is marked by the psychological feelings that come with a high level of fitness. This is characterised by an enjoyment of the activity while it’s being carried out. The rewards are totally intrinsic and the exercise becomes enjoyable in itself. Once you reach this stage, it becomes much easier to maintain a lifetime exercise routine, which, in turn, will help you maintain a low body weight.
AIM FOR A FEELING, NOT AN EFFECT Exercise is a vital part of any weight management program. But it shouldn’t be seen as a panacea. Some reasons for the relatively modest effects of exercise on fat loss have been outlined above. The benefits of exercise can, however, be wide ranging and include feelings of wellbeing, better sleeping patterns, increased alertness and increased ability to function during the day.128 Developing these benefits should be a primary goal of any exercise program. Loss of body fat can occur as a consequence of this, but it should not be seen as the sole function of an exercise routine.
DO SOME MODERATE EXERCISE BEFORE BREAKFAST Although time of day has not generally been considered important for influencing fat burning in exercise, some recent research has begun to question this. One study carried out at the University of Lausanne in Switzerland compared the amount of fat burned up as energy exercising before breakfast with that burned up exercising after breakfast.129 The researchers found that approximately 40% more fat is used up when exercise is done before eating, and after an overnight fast (see Figure 6.2). They explained this as being due to the low levels of blood sugar available as a result of the 8–10-hour fast overnight. The body therefore calls on more fat to power the system. . . . approximately 40% more fat is used up when exercise is done before eating, after an overnight fast. 99
Professor Trim's - pages 24/8/06 10:00 Page 100
BECOMING SLIMMER
Of course this effect can be neutralised to some extent by eating immediately after the exercise, since fat is used for some time afterwards to continue to supply the muscles with energy. The Swiss research found not eating for about 45 minutes after exercise was enough to solve this problem. Figure 6.2 The percentage of fat and carbohydrate (CHO) used as energy during exercise before and after breakfast.
Meal
Exercise
Exercise
Meal CHO Fat
% of energy use
CHANGE DIET BEFORE EXERCISE—FOR THE VERY FAT When you gain weight, you put on lean body tissue (muscle) as well as fat. This extra muscle is necessary to carry around the extra weight. Similarly, when you lose weight, much of this (around 25%) is muscle and other lean body tissue. For a very big person this might not be such a disadvantage because it’s often a loss in total body mass that is important—at least initially. One possible disadvantage is the reduction in metabolic rate that can occur with food restriction alone. For many very big people, however, exercise can be quite uncomfortable, even painful. Therefore it becomes a tradeoff in the early stages between the possible drop in metabolic rate and the discomfort of exercise, which might compromise such a person’s adherence to the program.130 100
Professor Trim's - pages 24/8/06 10:00 Page 101
MOVING AND LOSING
Changing your eating patterns is the priority in the early stages, until sufficient body mass has been lost to make planned exercise, such as walking, more tolerable. You can maintain your metabolism in the early stages simply by increasing the amount of incidental activity you do during the day.
DON’T CUT FOOD INTAKE WITHOUT EXERCISING—FOR THE NOT SO FAT Although we’ve recommended that diets should not be used, overall food restriction is sometimes called for, particularly dietary fat restriction in a fat-loss program. Restriction of food energy, however, leads to a relatively indiscriminate loss of body tissue. It’s estimated that up to 25% of the weight losses in an obese person can come from muscle, and the remaining 75% from fat. In a person who is not excessively overfat, the losses in muscle can be even higher, up to 50% muscle. Because muscle is more metabolically active than fat, muscle loss of this magnitude can lead to a reduction in metabolic rate, which, in turn, can make it easier to store fat at a later stage. For the slightly overweight, this can be a major disadvantage, because they can end up being fatter than when they started.131 This dilemma worsens the greater the energy restriction. More muscle will be lost on an 800 kcal/3360 kJ per day diet, for example, than on a 1200 kcal/5040 kJ per day diet. Aerobic exercise can help maintain body muscle even while fat is being lost. Because muscle is being worked during aerobic exercise, the body becomes discriminating enough not to ‘cannibalise’ this as an energy source. Metabolism therefore remains high and fat loss (although not necessarily weight loss) can be maintained. Therefore, for the overweight (in contrast with the obese), diets or food restriction should never be undertaken without a regular exercise program. . . . for the overweight (in contrast with the obese), diets or food restriction should never be undertaken without a regular exercise program.
USE PHYSICAL ACTIVITY TO BANISH TEMPTATION It’s well known that one of the major stimulants to obesity is stress in its various forms. While acute stress generally leads to a decrease in eating, 101
Professor Trim's - pages 24/8/06 10:00 Page 102
BECOMING SLIMMER
chronic stress—in the form of grief, anger, distress or depression—can lead to an abandonment of inhibitions against overeating and drinking and a reduction in physical activity. In the long term, this can lead to an altered energy balance and an increase in body fat. The traditional responses to stress throughout evolution have been fight or flight, both of which involve a significant response of physical exertion or exercise. Physical activity such as walking can—if carried out as an alternative response to stress or the temptation to overeat—not only produce a distraction effect, it can also help reduce the physiological effects of the stress by relieving muscle tension. In this way, the stimulus–response connection between stress and overeating can be broken.132
COOL DOWN SLOWLY AFTER EXERCISE During any form of physical activity the body’s rate of energy use is increased. If this is carried out over an extended period at a low–moderate intensity, fat will be liberated from the fat cells to help fuel the extra energy needs. Research on the role of fat metabolism during and after exercise shows that fats released from the fat cells remain in the bloodstream for some time, to be either ‘oxidised’ in the muscles or returned to the fat cells if not utilised.133 Cooling down quickly, by showering, for example, reduces the effort required by the body and therefore the amount of excess energy burned. A gradual cool-down, on the other hand, helps maximise the exercise effort. It also decreases the risk of muscular injury that could result from not allowing circulating blood to re-supply tired muscles.
WAIT A WHILE BEFORE EATING AFTER EXERCISE A general recommendation for athletes is to replace the energy used during exercise immediately afterwards by eating carbohydrate-rich foods. But while this is necessary to replace energy for fitness, it could be counterproductive when exercise is being used to reduce body fat.134 . . . more fat is used as a result of an exercise session if food is not ingested for 30–45 minutes after exercise. After exercise, circulating blood fats continue to be used as energy in the muscles to fuel the extra energy requirements of increased metabolism. If food 102
Professor Trim's - pages 24/8/06 10:00 Page 103
MOVING AND LOSING
is eaten immediately after exercise, and particularly if this is high in carbohydrate, which is quickly converted to blood glucose, this will be used as the preferred source of energy. Circulating fats will then be less likely to be metabolised and hence will be replaced, or re-esterified in fat cells. More fat is likely to be used as a result of an exercise session if food is not ingested for 30–45 minutes afterwards. This also allows time for a gradual cool-down.
TRADE OFF WALKING FOR INDULGENCES If a weight-management program is strict and inflexible, it’s likely to be abandoned at the first small transgression. For this reason, any program, to be sustainable for a lifetime, has to allow for occasional indulgences.135 There’s a psychological process involved in accepting this philosophy. If you allow yourself some transgressions, it becomes easier to accept them without feelings of failure. However, there’s also a physiological process at work here that you can capitalise on. Indulgences usually involve too much energy input, or kilojoules. You can compensate for this by increasing your energy output, or exercise. The approximate energy value of a standard alcoholic drink is around 100 kcals (420 kJ). In an average-sized person, about this amount of energy is required to walk one kilometre. Hence, trading off each drink with an extra kilometre of walking will help overcome any negative effects of the indulgence, and make life livable. Other common indulgences that can be traded off by doing some extra walking or other exercise are chocolate, weekend breakfasts, business lunches, festive season overimbibing and dinner at your in-laws’.
FORGET MOST CALLISTHENIC-TYPE EXERCISES Most ‘fitness’ books and articles in popular magazines on fitness invariably have a section on callisthenic-type exercises, which use the body as its own form of resistance. These, we’re told, will lead to increased fitness, muscular strength and even, if you’re lucky, the body you’ve always desired.136 The main function of exercise in a weight-management program is to burn energy, preferably fat. Because of their limited duration and specific muscle orientation, callisthenic exercises have little fat-burning value compared with extended-duration aerobic activities such as walking or cycling. It’s a bit like the difference between the petrol used up by taking your car for a long drive compared with that used up revving it up a few times on the spot. Callisthenic exercises might be good for toning up 103
Professor Trim's - pages 24/8/06 10:00 Page 104
BECOMING SLIMMER
muscles. But concentrate on getting rid of the fat so you can see your muscles before you even think about trying to tone them up!
FORGET THE SIT-UPS: GO FOR A WALK Because women usually store fat around the abdomen and because sit-ups work the abdominal muscles, it’s often assumed that the best cure for this kind of problem is thousands of sit-ups. Fat is metabolised through long, continuous, general aerobic activity, whereas sit-ups work a specific muscle group. Because underlying muscle is toned up through sit-ups, sit-ups—in the absence of a general aerobic program—will only serve to give you a tight, fat belly instead of a loose, fat belly. The fat is likely to remain.
IGNORE EXERCISES FOR ‘SPOT REDUCTION’ Many people think that to reduce fat on a certain part of the body all you need to do is exercise that part of the body. If this were true, gum-chewers would have skinny faces! Fat is stored in fat cells all over the body. It is taken from these cells as a fuel source for muscles in an order determined by gender, genetics and a range of other factors. As a general rule, it first comes off the last place it went on. So if you’ve become sturdier around the middle recently, the first place fat will come off—even in response to an exercise that doesn’t use the abdominal muscles, such as walking—will be the waist. Specific exercises for the gluteal muscles, often promoted as reducing fat on women’s buttocks, might even have be counterproductive. Lower body fat in women is known to be resistant to the normal stimuli that cause a breakdown of fat, probably because of the need for this fat as an energy reserve in pregnancy. Exercises for the gluteals might then increase the size of the gluteal muscles but not result in any fat loss, at least not from this part of the body.137
IF WALKING IS A PROBLEM As stated from time to time in this book, walking is one of the best forms of exercise around for weight control.138 However, because it’s a weightbearing exercise (meaning the body’s own weight is carried), walking might not be suitable for some people, such as those with lower limb injuries. In these cases, a weight-supporting exercise such as cycling, swimming, aquarobics or rowing can be substituted for walking. 104
Professor Trim's - pages 24/8/06 10:00 Page 105
MOVING AND LOSING
This might appear to be contradictory advice, since we eliminated swimming elsewhere as an efficient fat-loss exercise. But where other forms of weight-bearing activity are unsuitable, this could be your best option. Aquarobics, or exercises in water, is an even better option, as it involves using large amounts of energy with little discomfort. Other weightsupporting exercise options are cycling, rowing, canoeing or paddling.
NOW, PUT IT ALL TOGETHER As we’ve seen, exercise for fat loss can be quite different from exercise for fitness. We’ve looked at the importance of incidental plus planned exercise. We’ve also looked at different types of exercise. But just so it stays clear, we’ve displayed the recommendations for exercise for fat loss in a pyramid, modelled after some work on exercise for health. Check the pyramid and see whether what you’re doing—or, more important, what you plan to do— is right for you. Figure 6.3 shows the National Physical Activity Guidelines for Australians, developed for the National Health and Medical Research Council in 1999. Figure 6.3 National Physical Activity Guidelines
If you are able, also carry out some regular vigorous activity
3–4 days/week
Put together at least 30 mins of moderate-intensity physical activity on most days Be active every day in as many ways as you can Think of movement as an opportunity not an inconvenience
Most days
Daily
Always
105
Professor Trim's - pages 24/8/06 10:00 Page 106
Chapter 7 MAINTAINING YOUR LOSSES
INTRODUCTION Anyone can lose weight. Losing fat is a more difficult proposition. Even so, it’s not so hard to lose fat if you know a little bit about food and exercise, and apply a few principles such as those outlined in this book. But keeping it off—well that’s a different story. The reported long-term success rate for most weight-control programs is understood to be somewhere between 5% and 20%. That is, only 5–20% of those attempting to lose weight are successful at keeping it off for up to two years (in scientific terms, any measurement period shorter than two years is not to be taken seriously). The problem is that the human body was designed to gain and lose fat as conditions dictate. This is important from an evolutionary perspective because gains in fat in the good times mean a greater chance of survival in the bad. If losses happened easily, we humans wouldn’t have survived the lean times throughout history to get us to today’s situation of plenty. Unfortunately (at least in this day and age), it’s much easier to gain than to lose. To resist fat losses, the body adapts by reducing the rate of energy it burns at rest (the metabolic rate) and during activity, and increasing hunger levels. Where food is freely available (such as in today’s ‘supermarket’ society), these changes in body function can be just a little too hard to resist. So back go those precious kilos that you’ve fought so hard to lose—unless . . . unless by understanding the principles of the body’s adaptation you can turn them to your own advantage. Some important techniques are outlined in this chapter.
LEARNING THE TECHNIQUES FOR MAINTAINING WEIGHT LOSS According to Dr Tom Wadden, a psychologist from the University of Pennsylvania, the clues to successfully maintaining fat loss come from 106
Professor Trim's - pages 24/8/06 10:00 Page 107
MAINTAINING YOUR LOSSES
studying the habits of those who are successful in the long term.139 This kind of observation would suggest that: • • • •
although diet might be important when it comes to losing weight, those who develop a lifetime pattern of exercise do better at keeping that weight off maintenance is more successful in women who take long, regular (although not necessarily vigorous) exercise, such as walking people who regularly eat just one fatty food have no increased risk of regaining weight, but those who eat two or more are following a recipe for relapse individuals who keep weight off most successfully: ■ ■ ■ ■
•
don’t count calories, but develop a personal eating plan exercise regularly monitor their weight closely monitor their food intake
the best kind of maintenance comes from setting realistic goals; in some severely obese people, there might be biological limits to significant reductions in weight—being satisfied with achieving more modest goals can help.
In other research, it’s been shown that the best long-term maintainers are those who also have a well-developed means of dealing with stress. This prevents any relapse into overeating or underexercising in times of psychological upheaval.
COMING BACK FROM OBESITY IS HARDER According to Danish scientists, people who have lost large amounts of weight have more trouble keeping it off than lean people do staying lean. This might, to some extent, be because there are differences in the rate at which formerly fat people and lean people burn food as energy after a meal.140 If a meal is high in fat, people who were once obese tend to store this more readily in their body’s fat cells and rely more on blood sugars from carbohydrates as an energy source. . . . people who have lost large amounts of weight have more trouble keeping this off than lean people do staying lean. 107
Professor Trim's - pages 24/8/06 10:00 Page 108
BECOMING SLIMMER
The body has a limited ability to store blood sugars from carbohydrates (it holds only about 450 g or 2100 kcals/8820 kJ in total), so the greater carbohydrate usage in formerly fat people leads to a depletion of these blood sugars. Low blood sugar signals hunger to the brain, and this increases the likelihood of food intake as a result. This means that someone who has previously been obese but who has lost a lot of weight needs to take even greater care than usual with fat in their diet. Losing fat, it seems, is only the beginning. Keeping it off is the main game.
ACCEPT GRADUAL WEIGHT LOSSES Fluctuations in body weight are accompanied by physiological adaptations designed to restore the body’s status quo. In particular, a sudden decrease in body mass will lead to a slowing of metabolic rate and an increase in appetite. Decreases of over 1.5 kg per week have been shown to be associated with an increased risk of gallstones and a range of other possible health problems. You can expect large, sudden changes to result in significant adaptations, which might ultimately be counterproductive for long-term fat loss. Gradual losses, on the other hand, give the body time to adjust to changes with less of a negative impact. Medical research has shown that health risks are associated with large, sudden weight losses.141 Decreases of over 1.5 kg per week have been shown to be associated with increased risk of gallstones and a range of other health problems. Hence, a recommended safe rate of loss is between 0.5 and 1 kg per week. If a waist measurement is set as the goal (as it should be, particularly for men), about a 1% loss per week is recommended on programs such as GutBusters.
SETTING SHORT-TERM AND LONG-TERM GOALS Most people have set themselves a long-term goal when they take on a weight control program. But working towards a long-term goal only can be self-defeating, because achieving it is such a remote prospect and progress 108
Professor Trim's - pages 24/8/06 10:00 Page 109
MAINTAINING YOUR LOSSES
can be interrupted by plateaus along the way. It’s advisable therefore to have long-term outcome goals and short-term process goals, which can be used as milestones along the way.142 Goals could take a week, a month or a year to achieve, but they should all be clearly defined. Process goals are just as important as outcome goals because they tell you you are on track to achieve the outcome. Achieving outcome goals might be delayed because of plateauing (see below), but if the intervening process goals are reached, there is at least some reinforcement to continue. Process goals include: 1. 2. 3. 4. 5. 6. 7.
cutting fat back to 40 g a day walking six days a week walking a set distance each day reducing total food intake not eating a particular fatty food increasing daily energy expenditure cutting back on margarine or butter.
Table 7.1 Process measures in obesity management Energy intake • Daily intake of certain foods increased (say 3 fruits, 4 vegetables) • Reduced intake of high energy dense foods • Breakfast eaten daily • Daily fat intake kept below 30 g • Only foods with 30 g/day) • Regular healthy snack foods eaten • Frequent daily fluid intake (not including alcohol!)
Energy expenditure • Daily steps taken/distance walked • Minimum days of exercise classes • Improvements in time taken to exercise, (say walk 1 km in less time) • Increasing distance covered (walking, swimming) • Minimum days/week for planned exercise • Not using effort-saving devices • Carrying out ‘incidental’ activities • Car usage decreased • More gardening • More outdoor activity
DOING IT FOR LIFE Long-term weight loss means making changes that are sustainable. It’s not feasible to expect to stay on a diet for life.143 This is why diets don’t seem to work. One cannot, for example, expect a middle-aged man to stop drinking 109
Professor Trim's - pages 24/8/06 10:00 Page 110
BECOMING SLIMMER
alcohol and stay off it for the rest of his life. More to the point, once these sacrifices are abandoned, the likelihood of the whole program being abandoned increases. It’s not feasible to expect to stay on a diet for life. This is why the failure of diets can be confidently predicted. Any changes introduced to reduce body fat and maintain long-term weight loss must be changes that can be sustained for life. And while some changes might take a while to adjust to (for example, it can take from two weeks to six months to get used to eating low-fat meals), most will improve your sense of wellbeing and make you want to keep them up. The moral is ‘. . . if you can’t imagine yourself doing it for life, do something else’.
AS LONG AS YOU’RE NOT GAINING, YOU’RE WINNING Any loss of weight is accompanied by adjustments within your body, which make further losses more difficult. In a sense, the body fights losing its equilibrium level of body fat—the level to which it has become accustomed.144 It does this in three main ways: 1. A decrease in metabolic rate. As about 70% of the body’s daily energy expenditure is accounted for by metabolic rate, even a small change in this rate can have a large impact on body fat stores. Research shows that adjustments to metabolic rate actually counteract decreases in body mass, i.e. a 10% loss in weight might lead to a 20% reduction in metabolic rate, thus tending to slow, and perhaps even reverse, any decline in weight. 2. Changes in body composition. Not all the weight that is lost in a typical weight loss program comes from fat. In fact, the average overweight person loses about 25% of their weight from muscle. Because muscle is more metabolically active than fat, this means a decline in the overall rate of energy use, which in turn slows down the fat loss process. 3. Increases in hunger and appetite. Reductions in body weight are usually balanced centrally (in the brain) by increases in appetite, which reduce the long-term effectiveness of the fight against fat loss. In many cases these increases in appetite are so subtle that they’re not noticed. But the outcome, in terms of energy intake, is certainly recognised by the body. 110
Professor Trim's - pages 24/8/06 10:00 Page 111
MAINTAINING YOUR LOSSES
Natural decreases in body weight don’t happen in a linear fashion, but in a series of plateaus, as shown in the graph below. The length of the plateau and the size of the drop-off plateaus probably depends on the length of time the body spends at the level concerned. The main thing is to recognise that being on a plateau means you’re winning! Only when you start gaining weight again do you start losing the battle. Figure 7.1 Actual and expected trends in weight loss
Actual fat loss
Fat loss
Expected fat loss Goal
Time
GETTING OFF PLATEAUS Plateaus occur largely as a result of the body adapting to a different energy balance, either in the form of reduced energy input or increased energy output. Theoretically, at least, you might be able to get off a fat-loss plateau by reducing your body’s ability to adapt.145 You would do this by changing something. In relation to exercise, this could be: 1. Intensity—increase the speed at which you do your exercise. 2. Duration—exercise for longer periods, if possible. 3. Frequency—exercise more regularly (for example, by adding ‘incidental’ exercise during the day). 4. Type—vary the exercise you do, combine walking with cycling, swimming, aerobics—anything you like doing. 111
Professor Trim's - pages 24/8/06 10:00 Page 112
BECOMING SLIMMER
On the other side of the energy equation—food intake—you can help get off plateaus by: 1. Decreasing calorie intake—but only where this is still high. 2. Increasing calorie intake—by re-feeding where the calorie intake has been too low (under 1000 kcals/4200 kJ per day) and has been at that level for long periods. 3. Further decreasing fat intake—to reduce the appetite as well as calories. 4. Changing the food type—eating foods that the body is not familiar with or that you haven’t had for a long time (but that are still low in fat).
SMALLER DROPS AND LONGER PLATEAUS The body adjusts physiologically to changes in body mass by changing metabolism, hunger and the rate at which energy is burned for a given amount of exercise. If being overweight or obese has been a persistent problem, these physiological adjustments become more unyielding. It’s as if the body is saying to itself: ‘I’m fine at this weight—at least I’m alive— so I’ll fight to stay here’. Fat losses are therefore likely to be smaller and plateaus, during which no weight is lost, are likely to be longer, depending on how long you were overweight or obese: this is shown in the graph below. Anecdotally, we would have to say that this is not always the case. But if you’ve been fat for a long time, you can’t expect to get skinny overnight. Figure 7.2: Fat loss in the long-term and short-term overweight Long-term obese
Fat loss
Short-term overweight
Goal
Time 112
Professor Trim's - pages 24/8/06 10:00 Page 113
MAINTAINING YOUR LOSSES
PERSISTENCE IS THE KEY The longer you’ve carried extra weight, the harder your body is likely to fight to keep it. And while plateauing is an inevitable part of any weight loss program, it’s likely to be even more intractable for those of you who have been obese for a long time. In some cases the body can resist a weight change for months—even in the presence of significant changes in energy balance.146 Where this is the case, you might notice other metabolic improvements: you might feel fitter, be sleeping better, even feel a little lighter, although you might actually be heavier (because of an increase in the ratio of muscle to fat owing to exercise). However, the body can’t resist forever. Ultimately, it will have to adjust to the fact that the new energy balance is now the status quo. This will only happen if you persist. If you’re confident that you’ve made the proper changes (and you’re not kidding yourself about the amount of food you’re eating or exercise you’re doing), persistence will eventually pay off. It might not happen overnight, but it will happen.
REDEFINING SUCCESS Short-term losses in weight shouldn’t be thought of as the only measure of success in a weight control program. Short-term, rapid weight loss is usually short-lived; only success over a two-year period or more is to be regarded seriously. What is more important, it has now been shown that improvements in health and risk of disease can occur on a weight-control program without any apparent loss in weight. These improvements are usually accompanied by feelings of wellbeing, improvements in self-esteem and even some changes in body composition (as seen in fat loss but muscle gain). Success therefore needs to be redefined to include less obvious things (well, less obvious than fewer kilos registering on the scales), and these are: • • • • • • • •
decreases in medication improved quality of life and feelings of wellbeing increased physical activity reduced fat intake better digestion better sleeping patterns more energy during the day less tiredness. 113
Professor Trim's - pages 24/8/06 10:00 Page 114
BECOMING SLIMMER
If you take these as signals of success, you will be less fixated on actual weight loss. This can often have the paradoxical effect of leading to greater weight loss in the long term.147
MANAGING STRESS AND DEPRESSION Long-term, chronic stress (and/or depression) affect body fat levels because they can:148 •
•
•
•
•
•
Encourage nervous overeating. In some people stress diminishes the appetite, but others are driven to pig out to the max. It’s not simply a matter of nervous hands. Food provides a kind of comfort—it feels good when all about you might seem bad. Increase alcohol consumption. Alcohol is a great way to ‘blot out’ the effects of stress. After a few drinks you can live out whatever fantasies you have about solving your problems. The trouble is, it doesn’t last. Alcohol is a short-term solution for stress. Immobilise. Feeling that you don’t want to move is a symptom of severe or chronic stress. Not moving means not burning up energy. Not burning up energy means getting fat. Animals that are put in unremitting stressful situations from which they can’t escape actually give up and become totally immobilised. Psychologists call this syndrome ‘learned helplessness’. A similar thing can happen to humans. Decrease sense of self-control. Loss of control over one’s life is one of the main symptoms (and causes) of stress. If this flows through to other facets of life, control over waist loss and health practices will also be lost. Increase mobilisation of fatty acids. One of the (apparent) benefits of stress is that it causes fats from fat stores to be mobilised to be used as energy. However, if there’s no accompanying movement or exercise to use up this fat, it will remain in the bloodstream and can tend to clog arteries and cause heart problems. This is one of the main illeffects of stress. Decrease self-esteem. For many individuals, an increase in stress leads to a reduction in self-esteem, which flows through to affect all other facets of life. Including fat control.
Coping with stress is an important element of long-term weight management. So stress management is often an indirect way of facilitating longterm weight loss. 114
Professor Trim's - pages 24/8/06 10:00 Page 115
MAINTAINING YOUR LOSSES
FESTIVE FLUCTUATIONS One of the biggest dangers for anyone on a weight-reduction program is the festive season. Temptations abound—parties, dinners, drinks—and there is much time for working it off physically. The typical advance is retreat. You know you’re not going to win at this time so you might as well fatten up and enjoy it. The trouble is, there will be a payback time—and bills always seem to come around sooner than cheques! If your adult body weight is more than around 8–10 kg than your body weight at age 20 . . . , it might be time to start to do something about it. A more realistic approach would be the ‘passive pause’. Don’t worry about not continuing to lose. As long as you’re not gaining, you’re ahead. You can always get back on the wagon when things die down. And it’s not nearly as hard to climb back on the wagon if you haven’t fallen hard on your head. English obesity expert Dr John Garrow has shown that small gains and losses in body weight during the course of a lifetime have no apparent illeffects on health.149 If your adult body weight is more than around 8–10 kg than your body weight at age 20, on the other hand, it might be time to start doing something about it.
DON’T WEIGHT CYCLE Researchers at The University of California (Los Angeles) claim that although being fat is unhealthy, constantly yoyoing from fat to thin (weight cycling) has even greater health risks. ‘Most studies done on weight variability show that the greater the number and magnitude of weight changes, the greater the risk,’ says Dr Judith Stern, head of Nutrition at UCLA’s Davis campus. A possible reason for this is that in the weight-loss phase, muscle is lost as well as fat. When weight is regained, it’s regained just in the form of fat, and this can be in the dangerous intra-abdominal area. Research from the University of Minnesota indicates that the bigger the weight gain from age 20 to adulthood, the greater the risk of suffering or dying from a weight-related disease: diabetes, heart disease, stroke, cancer, and so forth. ‘Weight gains of 20 lb (9 kg) increase the risk dramatically,’ 115
Professor Trim's - pages 24/8/06 10:00 Page 116
BECOMING SLIMMER
says Dr Robert Jeffries.150 Although it’s probably not so bad and even natural to put on some fat in later life, too much can be too much of a burden. Stability, it seems, is the name of the game. And preferably stability at your weight around age 20. Health problems of too-rapid weight loss: • gall bladder disease • altered sleep patterns • anaemia • constipation • irregular menstruation • eating disorders.
DON’T WEIGH, MEASURE There has long been controversy about the best measure of body fat to use in a weight-loss program. Weight doesn’t necessarily reflect fat (although it’s often a good indication). However, more accurate measures of body fat are usually too complicated or too expensive. Attempts to arrive at a better measure of body fat than weight are often sidetracked into complicated and expensive measures and techniques. But researchers at the University of Glasgow have shown that a simple measure around the waist is as good as most other complicated measures.151 The researchers, in the University’s Department of Human Nutrition, compared waist to hip ratio measurements and body mass index (weight divided by height squared) to get cut-off points for recommendations for the general public. . . . bathroom scales are not only unnessary, they are downright undesirable. Measuring around the waist, midway between the iliac crest (top of the hip bone) and the lower rib, they found that: 116
Professor Trim's - pages 24/8/06 10:00 Page 117
MAINTAINING YOUR LOSSES
• •
men with a waist circumference of more than 102 cm and women measuring more than 88 cm around the waist have an increased health risk and should reduce their body fat men with a waist circumference of 94 to 102 cm and women with one between 80 and 88 cm should be cautioned not to get any fatter if they want to stay healthy.
The easy-to-remember figures of 100 cm for men and 90 cm for women are regarded as functional cut-off points—irrespective of height—that indicate a threshold level for health risk. Waist measurements can also be used (particularly in men) as a good indication of progress in a fat-loss program, and weight may be used as a back-up measure to see if fat losses occur without losses at the waist level.
BMI NOT THE BE ALL AND END ALL The most frequently used simple measure of fatness has been body mass index (BMI), a measure of weight (in kg) ÷ height2 (in metres) BMI scores of between 19 and 25 are regarded as ‘normal’. BMI has tended to provide a reasonable indication of levels of body fatness in given populations. However, the use of weight in the equation makes BMI much less valid as a measure for individuals, or as a measure of change in body fat. Athletic men, in particular, are discriminated against because of high muscle mass, which also tends to be heavy. Body stature (musculature) can influence BMI measures in some females.
THE EFFECTS OF CRITICAL STAGES During certain stages in life it’s easy for things (like maintaining a steady body weight) to go wrong. Being forewarned is being forearmed, so awareness of the following critical periods might be crucial.152 Marriage Getting married, or its equivalent, is often a time when both partners tend to gain fat and lose fitness. Research carried out at Sydney University shows that this is particularly so for young men, possibly owing to a lower level of physical activity through involvement in organised sport and increased regular food intake. 117
Professor Trim's - pages 24/8/06 10:00 Page 118
BECOMING SLIMMER
Retirement from sport A high food intake is necessary to fuel the increased energy levels required for sport, and eating at this rate becomes a habit. Retirement from sporting activity is often sudden, with a drastic decrease in energy output and often, through habit, no corresponding reduction of energy intake, leading to increases, or rebounds, in fatness. Changing jobs Changes in the work environment can disrupt your downward body fat momentum. It’s not clear why this should be so, but common sense would suggest that changes in attitude and perhaps the desire to impress could have an impact. Middle age Decreases in metabolic rate, which occur at about 2% per decade from the age of 20, start to have a significant impact at around 40 to 50 years of age. Couple this with the stresses of mid-life, life changes at menopause and other problems that occur around this time and you’ve got a ready-made ‘fat rebound’. Be prepared for it. Grief and bereavement Bereavement is a period of chronic stress where fat control becomes less important than surviving. Exercise decreases and eating, particularly of comfort foods, increases. Depending on the circumstances, this can last for anything from a couple of months to a couple of years. Dealing with your loss is your priority at this time, but try at least to stay on a plateau. Divorce or separation Like bereavement, divorce or separation has the potential for considerable psychological disruption. Again, your primary concern is to deal with the psychological difficulties associated with this kind of radical change rather than to try to keep losing weight to schedule. Try not to put it on, and get through the problem. Periods of prolonged stress When you are stressed you won’t be as restricted by the usual barriers to selfindulgence. In some cases, particularly of acute stress, food intake is actually reduced and fat can be lost. In chronic, but non-life-threatening stress, the opposite can occur, as can an increase in drinking as a coping mechanism. Learn to recognise upcoming stress periods and to deal with them so that 118
Professor Trim's - pages 24/8/06 10:00 Page 119
MAINTAINING YOUR LOSSES
they don’t interfere with your weight losses. After all, getting fat again will only increase your stress levels! After quitting smoking It’s well known that smokers who quit will gain an average of around 3.5 kg of body weight over 12 months. This is due largely to the loss of nicotine, which elevates the basal metabolic rate, and to the reduced food intake associated with smoking (possibly because smoking gives you something to do with your hands). Still, it’s more healthy to be a fat non-smoker than a lean smoker. The fattening effects do pass after you have quit for a while. As a result of some prescribed medications There are a number of medications, including those prescribed for anxiety, depression, schizophrenia and tissue repair (such as cortisol), that can increase body fat. Check with your doctor if you suspect this and ask for an alternative drug if it’s available (see list on pages 16–18). During festive occasions For most people, festive periods—Christmas, Easter, birthdays, reunions and other cultural, religious and personal celebrations—are a time when enjoyment overrules austerity. And besides, life is for living. The main rule is to make sure you don’t go up again—even if there are no losses!
EATING LESS AND MOVING MORE WITH AGE Energy expenditure declines naturally with age, largely as a result of decreases in muscle mass of around 1 kg per decade. Metabolic rate consequently declines at a rate of about 2% per decade, which means that if you eat and drink and exercise in the same way as you did when you were young, you’re guaranteed to put on extra poundage naturally.153 The natural slowdown in energy use and growth requirements means that just to keep your weight stable as you get older would require either taking in less food and/or carrying out a little more exercise as the years advance. This suggests that you need to pay more attention to maintaining energy output or modifying energy input with age to ensure that your body fat doesn’t balloon. The natural slowdown in energy use and growth requirements 119
Professor Trim's - pages 24/8/06 10:00 Page 120
BECOMING SLIMMER
means that just to keep your weight stable as you get older would require taking in less food and/or carrying out a little more exercise as the years advance. As it’s usually not so easy to compete with your younger self on the exercise front, this generally means being more careful about your food intake. There is some good news in all of this. Research on animals, as well as humans, shows that those who eat less tend to live longer and remain healthier (but don’t go taking this to extremes!). But isn’t it a cruel stroke of fate that things don’t get easier just when you feel they ought to?
REDUCE YOUR EFFICIENCY As explained above, maintaining weight loss beyond a certain point is not only unlikely, it’s downright unhealthy. Your body adapts to stop you disappearing. And the way it does this is by becoming more efficient at doing what it does with the means at its disposal. Walking 3–4 km a day at the start of a program might be a bit of a shock to the system for most people. But after even a week or two, those muscles involved in walking spring back to life and do it quite easily. For example, where it took around 100 kcals (420 kJ) to walk 1 km in 12 minutes at the start, now it might only take 80 kcals (376kJ). In addition, because you’ve lost a couple of kilos of fat, your body doesn’t have to work as hard to keep you alive (your metabolic rate). Both these facts mean you’ve become more efficient, and you’re using less energy—and less fat—in the process. Strangely enough, you need to become less efficient again to burn more energy. Walking on your hands would do it, but that’s not always feasible (or advisable). But certainly changing the type, duration or intensity of your exercise is. Even changing the path you normally take for a walk, or the time of day you do it, might help. The same applies to the type of food you eat. It takes energy to digest food (more to digest carbohydrate than fat), and any change in eating patterns can increase total energy (and fat) loss. You need to become a less efficient eater if you want to get off a fat-loss plateau. You can do this by trying some different foods—fruits and vegetables in season, for example, or something you rarely eat, like Mongolian or Tyrolean fare. Even try a different drink; gin and tonic instead of a beer, perhaps. If you’ve hit a fat loss plateau, or are about to, becoming less efficient could be just what the fat doctor ordered—even if it’s not what the productivity consultant desires.
120
Professor Trim's - pages 24/8/06 10:00 Page 121
MAINTAINING YOUR LOSSES
IF YOU HAVEN’T MUCH TO LOSE The weight you lose consists inevitably of muscle and fat. The proportion of muscle to fat you lose when dieting decreases with your body’s increase in fat to muscle ratio. The amount of muscle lost also depends on the method used to lose weight—if muscle is used, such as through physical activity, it’s less likely to be metabolised for fuel than if the mode of weight loss caused by food restriction alone.154 Food restriction alone becomes more counterproductive to fat loss the less body fat there is to lose—a point that is often lost on many dieting young women trying for that anorexic model look. Muscle loss, in turn, can be counterproductive in a fat-loss program because it results in a decrease in metabolic rate and therefore the potential for a greater increase in body fat at a later stage. A relatively lean person with only a small amount of fat to lose would lose a greater proportion of muscle than fat on a food restriction program than a person with more fat to lose. Food restriction by itself is more counterproductive to fat loss the less body fat there is to lose. The best way for people who aren’t too overweight to lose weight is to increase their activity level.
BEWARE THE CHANGE OF SEASONS Seasonal affective disorder (SAD) is a phenomenon found in a small group of weight-sensitive people.155 The disorder is characterised by large gains in weight in the winter, often accompanied by losses instigated by purging and severe food restriction in summer. SAD is usually more common in countries with large extremes between the seasons. It’s thought to have a physiological cause, and to be brought on by lack of daylight, possibly affecting a chemical called melatonin which is involved in skin tanning and body bio-rhythms (melatonin has recently been prescribed for the prevention of jet lag in long-distance travellers). Research is now also examining the effects of artificial light on reducing SAD. Although it’s a reasonably rare phenomenon, a minor form of SAD might occur in some people who tend to overeat and underexercise in the winter months. Awareness of the effects of the change in seasons could help overcome this, but we can’t guarantee it. If you think you suffer from this, light treatment from a special therapist might help. 121
Professor Trim's - pages 24/8/06 10:00 Page 122
BECOMING SLIMMER
MAKE SURE YOUR ‘ARTHRITIS’ IS REAL Big people tend to be afflicted by more knee problems than lean people. This is often diagnosed as arthritis—which gives the patient an excuse for not carrying out weight-bearing exercise, such as walking, which is most likely to help decrease weight. Without exercise, increased weight gain becomes more likely. This makes things worse for the knees, and so the vicious cycle continues. British researchers have deduced that much of what is considered to be arthritis in big patients is simply the mechanical pressure of carrying excessive body weight.156 To test this, they compared a sample of 525 men due to be listed for surgical treatment of the knee with 525 other men matched for age and consulting the same doctor. The researchers found that the risk of knee problems increased with increasing body weight. Men who were below normal body weight, as measured by a body mass index (BMI) of 36, the risk of knee problems increased 18-fold compared with men with a normal BMI level of 19–25. This led the researchers to calculate that if overweight people could decrease their body weight by just 5 kg, 24% of surgical cases of knee osteoarthritis could be avoided. Of even greater concern in this study was the fact that individuals with a history of knee injury as well as being obese had 78 times the risk of knee problems requiring surgery! The verdict clearly is that many knee problems are not really arthritis, and that the best way to avoid the knife is to reduce the weight.
122
Professor Trim's - pages 24/8/06 10:00 Page 123
Chapter 8 THE GOOD, THE BAD AND THE UGLY
INTRODUCTION Everyone who’s overweight wants a magic pill. They’d like to take it at night, so they can wake up in the morning and be slim, trim and terrific. Unfortunately, it’s not as easy as that. Extra fat, like extra money, takes a long time to accumulate. But unlike extra money, it also takes a long time to get rid of. There are lots of shady dealers out there who’ll try to convince you that if you spend your extra money with them, they’ll spend your extra fat at the same rate. New products and programs for weight loss pop up faster than pimples. Most will disappear as quickly, but in the meantime their backers will have quietly pocketed your extra wallet fat and moved on to the next fad. Of course, not all new products and programs are bad. The move to low-fat foods, the development of new exercise machines and controlled behaviour modification programs, for example, can all have benefits (although none should be seen as ‘magic’). We’ve grouped a range of these under the heading ‘The good’ in the pages that follow. On the other hand, there are products that either counteract any effort you might make to keep your body weight down or are likely to be neutral in effect. I’ve considered some of these under the heading ‘The bad’. This doesn’t mean you have to avoid them completely, just use them in moderation and arm yourself with the facts about them. Finally, there’s what we call ‘The ugly’. These are products with no acceptable scientific backing, sold with the sole purpose of making their marketers fat on the proceeds. Pick your way through ‘the good’, try to find your way around ‘the bad’ and don’t let yourself be fooled by ‘the ugly’. Perhaps I should add that I haven’t been paid or given any other form of consideration for assessing any of these products/programs. 123
Professor Trim's - pages 24/8/06 10:00 Page 124
BECOMING SLIMMER
THE GOOD Low-fat Fruitfuls hit the spot Fruit biscuits might be expected to be just that—fruit-full. And so they would be if it wasn’t for the pastry used for the biscuit part. Unfortunately, wheat flour contains some oils and oil has to be added to the flour to make a workable dough. However, food technologists at Arnotts biscuits have devised a fermentation process that optimises the activity of the yeast and lactobacilli, which make up the microflora of a fermenting dough. By combining this with a yeast mix at the mixing stage, only a minimum of fat or vegetable oil needs to be added. This has formed the basis of a new fruit biscuit from Arnotts called Fruitfuls, which meets all the requirements for a low-fat (3% fat) tasty snack. The fruit in the biscuit is also specially prepared with a unique process developed in New Zealand. It protects the biscuit from spoiling and increases the intensity of the taste. A word of warning, though. If lowering the fat in your diet has not been enough for you, you might need to view biscuits such as Fruitfuls in a different light as they are high in energy density (see Chapter 5), with sugars making up for the decreased fat.
Undressing salad dressings Usually made from an oil base, salad dressings normally represent an energydense way of topping an otherwise low-energy salad. Some manufacturers are now giving us the option of vinegar-based dressings that taste quite similar to the real thing. Both Kraft Free and Kraft Light have absolutely no fat, as does the range of Praise No Oil salad dressings. Kraft also provides