Exercise?
A Fat Lot of Good That Does for Weight-Loss

by Helen Rumbelow

In 1932, Russell Wilder, one of the leading obesity experts, lectured the American College of Physicians, saying that his patients lost more weight on bed rest than an exercise regime.

It’s one of those ha-ha moments of medical history, along with doctors prescribing cigarettes to patients to “clear the lungs”. Now we all know that exercise is the best way to lose weight, in the same way that we all know that our obesity epidemic is a result of Western sloths sitting on our ever fatter bottoms. It’s why chubby will be the new norm, with 90 per cent of today’s children predicted to be overweight or obese adults by 2050, costing UK taxpayers £50 billion. It’s why the most insistent plank of the Government’s anti-obesity drive is exercise. It’s why we look at our pudgy kids and cry “To the playing fields!”, and prescribe them ever more PE. It’s why, every new year, we sigh at our expanding muffin top and resolve to Power Plate it away.

That exercise is the key to losing our collective weight is something that we know so deep in our cultural guts that to question it would be ridiculous.

Except that is what the most cutting-edge obesity researchers are now doing. The recent studies show that the benefits of exercise for weight loss have been overstated. This idea is shocking. It goes so far against the orthodoxy that it is not something many can accept. And certainly for governments and the food industry that places them under so much pressure, it is too much to swallow.

But, as Professor Boyd Swinburn, director of the World Health Organisation Collaborating Centre for Obesity Prevention, says: “This is provocative in many ways . . . but my concern is that if we put the emphasis on exercise we are unlikely to tackle the obesity problem as we are not driving at the root cause.”

The idea that exercise will help to shed pounds is fairly recent – emerging at the same time that obesity began to boom in the 1980s. Of the simple “eat less, move more” equation, many found the idea of moving more (while watching Jane Fonda in a leotard) infinitely more appealing than forgoing another slice of cake. In the intervening years, doctors have discovered that exercise reduces depression, heart disease, some cancers, diabetes, and dementia, to name but a few of its benefits. It has become obvious that as a species we live longer and healthier when we move around. One doctor told me: “Aside from not smoking, there is nothing better you can do for yourself than exercise.”

This has made doctors even more reluctant to reveal that exercise has proved a poor route to weight loss. A review of recent research by the respected Mayo Clinic in America concluded that “most studies have demonstrated no or modest weight loss with exercise alone . . . patients should have realistic expectations, an exercise regimen . . . is unlikely to result in short-term weight loss beyond what is achieved with dietary change.” (Although, it is important to note, few people can stop themselves getting fatter over time unless they are active.) Two separate studies, one by the Physical Activity and Weight Management Research Centre at the University of Pittsburgh, another by Timothy Church, director of the Laboratory of Preventive Medicine at the Pennington Biomedical Research Centre in Louisiana, came to the same conclusion. Both took groups of hundreds of sedentary women, and randomly assigned them different amounts of exercise for a year. In both studies the results were surprising. The women lost similar amounts of weight, no matter which group they were assigned to. In the latter study, even the group assigned no exercise lost a similar amount of weight to the exercisers. Weight, by the way, is still a good guide to fat loss in non-athletes. Church says: “As you get older it is hard to add significant amounts of muscle.”

What’s going on here? First, people have been shown to overestimate how many calories they are burning off in a workout – typically doubling the true figure. Anyone who “earns” a muffin with a jog has probably taken on more calories than they’ve just burnt. Second, exercise makes people eat more. “I don’t think they’re hungry, I think it’s a reward issue,” Church says.

The combination of those two effects can be disastrous. A study in the International Journal of Obesity last year followed 538 11-year-olds for 18 months, and found that if they started watching an extra hour of TV a day, they consumed an extra 100 calories. But it also found that if they spent an extra hour doing exercise, they consumed an extra 292 calories, on average. If the exercise was really vigorous, the children could still lose weight, but if it was moderate, it probably had the same effect on weight to the children who watched TV. The researchers, from the Harvard School of Public Health, concluded: “Watching TV is an activity associated with a daily energy surplus. Although physical activity is thought of as an energy deficit activity, our estimates do not support this hypothesis.”

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November 4, 2009

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