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The Exercise Myth
"The number of heart attacks occurring among the joggers should dampen the enthusiasm for this type of unsupervised sport among the laymen."
DR. Broda Barnes
Part 1: Exercise for weight loss
Introduction
Together with diet, exercise is touted as a cure for obesity, diabetes, hypertension and other associated conditions. But does this hypothesis stand up to objective scrutiny; just how much benefit is there really to undertaking a strenuous exercise regime; and can you have too much?
If you watch animals in the wild you will see that on the whole, they take as little exercise as possible. The lion, for example, spends most of his day lying down or asleep, yet he doesn't get fat or any other diseases. It is his wife, the lioness, who does the shopping. But she hunts only once every 2 or 3 days and even then expends as little energy as possible doing it. Similarly, grazing animals have a slow and steady lifestyle, moving quickly only when threatened by a predator. The same is true of modern hunter-gatherer human tribes. Any traditional Inuit, for example, is always prepared for maximum walking, but nobody does it for fun or for ‘exercise'. In the wild, nature protects the heart from stress.
Think about when our ancestors were hunter-gatherers. They had a good brain, but not a lot of speed. Did they chase their prey? It's not likely: there wouldn't be much point as the prey could all run faster than them. No, hunters either crept up on animals stealthily until they were close enough to throw something at them or they caught them in snares.
Animals that run for a living have efficient built-in shock absorbers in their legs; we haven't: merely the arch of the foot. We simply aren't designed to run; we are designed for stealth and for walking at a slow, deliberate pace which does not send shock waves up our lower limbs. It is not surprising, therefore, that our current love affair with exercise has resulted in a huge burden on the NHS from injuries sustained while running and jogging with a 10% per year increased demand for orthopaedic hospital beds as a result.
Exercise for weight loss
The combination of exercise and thinness is a well-established stereotype. The overweight are frequently criticised for not taking up the more strenuous physical activities enjoyed by slimmer people. Drs Andrew Prentice and Susan Jebb of the Medical Research Council pointed out that between 1980 and 1991 calorie intake in Britain fell by some 20%, while the number of people who were overweight doubled.[1] As we seem to be heeding the current dietary advice to eat less, but are nevertheless getting fatter, Prentice and Jebb conclude that the overweight are lazy. But are they?
Most modern diets advocate the twin strategies of taking in less energy (calorie-counting) while at the same time using more (exercising). And so dieters are urged to take up some form of physical activity to burn up the calories.
But the overriding philosophy that exercise is the only sure way to lose fat — has always ignored one important fact: it doesn't work! Every single study on exercise to date, regardless of the type of exercise, (aerobic, anaerobic, resistance training, split routines and combo approaches) has shown that exercise almost always fails to alleviate obesity — whether it is combined with a low-calorie or low fat diet or not. This really should not be surprising: surely everyone knows that, if they do more work, they get hungrier more quickly and eat more food. And the food they eat will be the same carbohydrate-rich food — candy bar, fizzy drink — that made them overweight in the first place. This form of ‘weight loss' is the best way to gain weight.
Not surprisingly, the great deal of research, carried out in the hope of demonstrating that exercise reduces weight in the obese, has been consistently unsuccessful — and very few studies have tried to discover why. Here are the results of some of them:
- In 1976 Dr Per Björntorp and colleagues at the University of Gothenburg, Sweden, studied normal and overweight subjects on a six-month course of physical training.[2] Although those at normal weight did lose weight on this programme, the overweight ones didn't.
- Two years later Dr Martin Krotkiewski and colleagues conducted a similar study.[3] They found that while mildly obese patients did tend to lose weight, severely obese patients actually put on weight. These findings were not confined to Scandinavia.
- In 1989 Drs I.E Yale, L. A. Leiter and E. B. Marliss, at McGill University, Montreal, and the University of Toronto, also found that exercise was fattening.[4] Measuring blood insulin levels, they discovered that insulin remained much higher in obese patients for more than an hour after exercising. This means that their bodies were taking glucose out of the blood and storing it as glycogen and fat.
- Studies published in the early 1990s found no causal relationship between low physical activity and obesity in either children or the elderly.[5]
- In 2000 a review found that the often-prescribed 3-5 hours per week of moderate to vigorous exercise had little or no impact on weight.[6]
There will be those who talk of doing very heavy work for long periods and who have lost weight. I lost a lot of weight myself when I was building my own house. But the amount of exercise which will be or can be realistically done by the average person is ineffective for significant weight loss. The caloric burn of aerobic exercise, especially at the intensities that most mortals can sustain, is low — perhaps 5 calories per minute. That's a fairly insignificant 300 cals per hour. So, even after exhausting exercise, you will probably use up less than 150 calories.
Children are the latest targets in the ‘war against obesity'. In 2006, the British Medical Journal online published a study of 545 children with an average age of 4 who exercised for 30 minutes, three times a week. It was studying the effects of the exercise on the children's body weight.[7] And did the children lose weight? No: all the additional exercise made no difference to their weight.
Research published in the American Journal of Nutrition assessed the relative role of calories intakes and calories burned with regard to body weight changes in children.[8] It found that calories consumed rather than calories burned accounted for 74% of variation in weight. This means that what is eaten is far more important that exercise done.
And I do mean what is eaten, rather than how much. Between 1977 and 1999, 20 studies considered the types of foods to determine which were more satisfying and staved off subsequent hunger. Sixteen of the studies showed that the lower the GI of foods, the better they were in this respect.[9] Significantly, an increase in GI of 50% reduced the satisfaction it gave by 50%! The best low-GI foods are foods such as meat, fish, eggs, cheese, butter, cream, nuts and vegetables other than starchy root veges such as potato and parsnip. The worst GI foods included most starchy carbs such as breakfast cereals, bread, pasta, and rice. Yet these are exactly the types of foods promoted for eating after exercise — ‘to top up glycogen levels'. In this way, the carb-laced snack quickly wolfed down at the end of a workout is all it takes to put back all the weight lost during it.
All this is borne out by the following case history which shows that there is no need to exercise to lose weight if you eat the right foods:
Case history
E.K. has multiple sclerosis. She was first diagnosed with MS when she was 19. That's now over 20 years ago. Almost all of that time she has spent in a wheel chair, getting no exercise at all. You won't be surprised to hear that over the years she put on a lot of weight. Eventually, she decided to adopt the low-carb diet I recommended — and it worked beyond her wildest dreams. She didn't weigh herself; she couldn't. But she did know what she measured. After less that a year on the low-carb, high-fat diet, she had gone down 3 bra sizes and, she told me, ‘it is getting expensive!'. Three years after starting the diet, she was down to a normal weight and size, and she has now maintained it for over 4 years.
The truth is that the current recommendation for 30 minutes of aerobic exercise 3 times a week as an effective way of losing weight is a bad joke, and the impact of aerobic exercise on various parameters of weight loss is severely overstated.[10] And contrary to popular belief, aerobic exercise does not raise metabolic rate after training. Probably the biggest benefit of aerobics is that it improves the muscles' ability to use fat for fuel, by increasing mitochondrial density and the activity and number of aerobic enzymes. But that is only of use if you use fat as an energy source rather than glucose from carbs.
Part 1: Exercise for weight loss | Part 2: Exercise and heart disease | Part 3: Dangers of Exercise | Part 4: References
Last updated 6 February 2010
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