Diets don't work — they actually cause weight gain, says nutrition expert Geoffrey Cannon. He tells Sophie Morris why he declared war on the slimming industry
The weight-loss industry is swelling as quickly as our waistlines at the moment, which seems something of a paradox. If body conscious consumers are so happy to buy dieting products, why are we facing an obesity crisis? The truth is, no calorie-controlled diet works. If they did, dieting professionals could kiss goodbye to repeat business. Even worse: restricting what you eat will make you fat. Worse still: yo-yo dieting can cause depression, high blood pressure and high cholesterol levels. Frequent dieters are 60 per cent more likely to die from heart disease than people who don't starve themselves.
The weight-loss successes trumpeted on the front of slimming magazines contradict this. They tell the stories of women (it usually is women) who have lost a lot of weight by following a diet which restricts calorie intake. As the pictures show, these women have clearly not been made fat by following such regimes. This, though, is only part of the complex dieting jigsaw, as Geoffrey Cannon explains in his book Dieting Makes You Fat. Yes, if you consume less energy than your body burns off in a day, your weight will drop. But Cannon, a public health adviser and nutrition expert, looks longer term, and says that nearly all dieters are forced to turn to drugs, surgery, further dieting or exercise to maintain that initial weight loss.
If the title of the book rings a bell, it is possible you read Cannon's earlier book of the same name, which he wrote 25 years ago. Conclusive new scientific evidence to support the claims in the first book, a global public health crisis caused by obesity and its attendant illnesses, and a booming diet industry prompted Cannon to completely rewrite this text.
Dieting Makes You Fat was ground-breaking a quarter of a century ago, but its message is perhaps even more urgent today. As people are getting fatter (a government report from 2007 predicted that by 2050 most British adults will be obese), the market for weight-loss products is growing. The dieting industry in the US is worth $46bn a year; in Europe it is worth ¤93bn. Clearly, our appetite for losing weight is not matched by our capacity to actually shed fat.
Why did we not take Cannon's advice the first time round? “When people are sceptical of dieting regimes they will say that diets don't work,” he explains. “But they always stop short of saying that dieting makes you fat, which is a concept with explosive implications.” He points to scientific studies which illustrate how the dieting trap leads to weight gain. A 2007 UCLA review concluded: “We found that the majority of people regained all the weight, plus more ... most of them would have been better off not going on the diet at all.”
Further evidence came from an experiment in a closed-off ecosystem in Arizona in the early Nineties. Eight scientists had agreed to live inside the man-made biosphere for two years. Once inside, they discovered they were unable to grow enough food, but agreed to diet for the two years and continue with the experiment. They all dropped about 9kg, before their weights stabilised. Within six months of leaving the biosphere, they had piled the weight back on, and — crucially — almost of all of it was fat, not the lean tissue they had started out with. Not only does dieting make you fat, it makes you flabby, too.
“Throughout history humans have evolved and adapted to survive famine and starvations,” explains Cannon. “The people who survived were the people who were best able to, those who had their larders inside themselves, in the form of body fat. A dieting regime will fail, because you're training your body to survive famine and starvation better.”
Cannon takes pains to dilute the science in Dieting Makes You Fat and includes just one table in the whole book, which looks at the difference between the energy our bodies burn at different weights and with different body compositions — whether lean (physically fit, but not necessarily light) or fat (not necessarily heavy, but with a high proportion of body fat to lean tissue). A lean woman who weighs 70kg (154lb) burns 600 calories more at rest per day than a 70kg woman who has lots of body fat.
What, then, is the answer to losing weight, if diets are out? Cannon says there are a lot of people out there who need to lose a lot of weight, without subscribing to the misconception that a thin person is a healthy person, and that fat people are unhealthy. Dieting Makes You Fat proposes seven golden rules for losing weight, the most salient being to take lots of exercise and eat plenty of fresh, whole foods. He writes from experience, having jumped on the dieting wagon at a young age himself. When he realised that the diets he tried were ineffective, he set about proving why.
You do need to wait six or seven months to see positive results, admits Cannon, but follow his rules and you will dig your body out of the dieting trap.
Dieting Makes You Fat by Geoffrey Cannon, Virgin Books, £16.99 in hardback