Diets can kill you

Published Jun 1, 2007

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London - Fighting the flab may not only be pointless - it could also be dangerous. This is according to one of the largest studies of the effects of dieting.

The review of 30 research papers involving thousands of slimmers found that although many of them succeed in shedding kilos while dieting, they pile the weight back on as soon as they stop, with most ending up heavier than they were to start with.

The University of California scientists who conducted the review, published in the journal American Psychologist, say this kind of yo-yo dieting may also be damaging to health. Research has shown repeated rapid weight gain and loss may increase the risk of heart disease, heart attacks and premature death.

People expend large amounts of energy and money buying special foods, joining diet clubs and counting calories.

They will suffer from the constant hunger and the loss of one of life's great pleasures - eating. And when they fail, as most ultimately will, they will feel guilt and self-hatred.

The Californian scientists found only a small minority successfully lost weight and kept it off over the five-year duration of the study.

The moral is: Do not waste time deciding which diet to follow. Lo carb or no carb, high or low fat, protein rich or poor - it makes no difference. It is not the diet that determines how much weight you lose but the rigour with which you follow it.

Simple - eat less and exercise more. There is no other way of losing weight.

All diets - and there are zillions of them - are designed to help dieters eat less. Some diets claim to alter metabolism so that you burn calories faster or absorb them more slowly.

But if there is any effect on the metabolism, it is minimal. The reason for the obesity explosion is that an energy imbalance has built up as we consume more and do less.

Over the past 30 years, consumption of calorie-rich fast foods and sugary snacks has risen while energy expenditure has declined with the increase in sedentary work and use of cars.

The result is seen in ever-expanding waistlines that can only be curbed by cutting calorie intake to match reduced energy spent.

The unacknowledged principle behind most diets is to make eating difficult. As there is only one way to lose weight - by eating less - inventors of diets have had to come up with ways of getting people to do this without noticing.

Some diets require elaborate preparation, or are very unappetising or bound by rigid rules. The aim is the same - to reduce the amount of calories consumed.

Teenage girls, driven to covet size zero fashions, are at greatest risk of taking dieting to extremes. One-in-100 girls aged 15 to 25 is said to suffer from the eating disorders anorexia and bulimia, which may have lifelong effects and in rare cases lead to death.

Extreme dieting is dangerous for adults too, depriving them of essential nutrients and leading to excessive consumption of certain foods in unhealthy amounts.

More than 45 million copies of the Atkins diet books have been sold since the 1970s, making it the most successful diet of all time.

The Atkins diet recommends unlimited consumption of butter, fatty meat and high-fat dairy products, while carbohydrate intake is restricted to 30g a day - equivalent to a small potato.

Although research suggests it is safe and effective at promoting weight loss in the short term, this is a diet practically guaranteed to induce heart disease in the long term.

Research shows that people who have stuck with the diet for more than a year tend to suffer headaches, muscle cramps and diarrhoea caused by carbohydrate deficiency. The minimum daily requirement of carbohydrate for an adult is 150g a day, but on the Atkins diet it is cut to one-fifth of that.

Despite the huge social and medical pressure on the overweight to shed their excess kilos, there is scant evidence that it will improve their health. What we know is that the overweight are at greater risk of ill health - from heart disease, diabetes, some types of cancer and joint problems. But it does not follow that losing weight will cut the risk.

We simply do not know whether a person who loses 10kg will thereby acquire the reduced risk of a person who started out 10kg lighter.

Yo-yo dieting increases the risks, as noted above.

The best way to protect health is to prevent children becoming obese in the first place, by eating healthily and exercising more.

It is far better to stop the weight going on than to find ways to get it off later.

Fruit and vegetables to replace cakes and dairy foods, recommended in many diets to promote weight loss, also reduce cholesterol and the risk of heart disease and cancer, and have been shown to cut the risk of Alzheimer's disease.

Fibre in wholemeal bread and cereals helps fill the belly and curb appetite, while also being good for the digestion and, according to some research, protecting against bowel and breast cancer.

This is the Mediterranean diet, long known to be protective against a range of chronic diseases.

More controversially, recent research has shown that restricting food intake to half the normal calories in a range of species from worms to mice can extend their lifespan. Eating less might help you live to be 100 - but life would be a misery.

The ideal diet is one that contains 600 calories a day less than the individual burns in energy, according to the United Kingdom's National Institute for Health and Clinical Excellence (Nice).

This is equivalent to cutting out one Bar One and one Danish pastry a day.

In its first official guidance on weight loss issued in December, Nice warned that crash dieting could be dangerous and recommended the 600 daily calorie reduction as the most likely to result in "sustainable weight loss". Wise advice - but unlikely to become a bestseller.

- People who are overweight or obese have an increased risk of heart disease, cancer and diabetes;

- There are social pressures, which can even show up in reduced income, to lose weight;

- If people feel unhappy with their body shape, they may be more confident and content if they slim down;

- Diets don't work in the long term as dieters tend to recover all the weight they lost and more;

- Dieting can put health at risk by encouraging excess consumption of certain foods;

- There is no evidence that losing weight reduces the health risks of being overweight. - The Independent

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