Don't worry what diet to follow: willpower is the key ingredient

If the bathroom scales reproach you with their tale of Christmas excess, here is a piece of advice: do not waste time trying to decide which diet to follow.

If the bathroom scales reproach you with their tale of Christmas excess, here is a piece of advice: do not waste time trying to decide which diet to follow.

A comparison of four popular diet plans, including Weight Watchers and Atkins, has shown that it is not the diet that determines how much weight you lose, but the rigour with which you follow it. Any diet will do so long as you stick to it, researchers have found. Low carb or no carb, high or low fat, protein rich or poor - it makes no difference.

The finding, published yesterday in The Journal of the American Medical Association ( JAMA ), suggests scientists may have to change their approach to the treatment of obesity. Instead of searching for the most effective diet to help people lose weight, they should be matching individuals to the diets that best suit them.

This new science, "nutrigenomics", could increase adherence rates among dieters and promote weight loss, they say. But there is currently no way for doctors to match a diet to an individual's "diet response genotype", the genetically determined way in which they react to certain foods.

It is known that success in dieting depends on the dieter's psychological determination to change. But the new research suggests that if a way could be found for individuals to select the right diet for them, it could ease the demands on willpower.

The finding comes as the dieting and fitness industries enter their peak January season, when millions of people seek to repair the damage caused by the festivities.

But the evidence suggests that up to half will fail. The researchers found that between 35 and 50 per cent of those who started the four diets had abandoned them within a year. Michael Dansinger and colleagues from the Tufts-New England Medical Centre in Boston assessed adherence rates and the effectiveness of four popular diets - Weight Watchers (restricting portion sizes and calories), Atkins (minimising carbohydrate intake without restricting fat), Zone (moderate macronutrient balance and glycaemic load) and Ornish (restricting fat).

They followed 160 overweight or obese adults aged 22 to 72 who had high blood pressure, high cholesterol, high blood sugar or other health problems who were randomly assigned to one of the four diets. After two months of making a maximum effort, the participants were left to decide for themselves for the remainder of the year how closely they followed their plans."All four diets resulted in modest statistically significant weight loss at one year with no statistically significant differences between diets," the authors write.

"We found that a variety of popular diets can reduce weight ... but only for the minority of individuals who can sustain a high dietary adherence level ... The higher discontinuation rates for the Atkins and Ornish diet groups suggest many individuals found these diets to be too extreme."Some doctors have also warned that the Atkins regime could do damage.

In a commentary in JAMA , Robert Eckel of the University of Colorado offers a simple answer to those seeking guidance through the plethora of popular diets. The best way to lose weight is to reduce calories and increase exercise, he says.

A RECIPE FOR WEIGHT LOSS?

Atkins

The voguish low-carb diet has exploded in popularity since being introduced. Detractors say it gives followers ban breath and skin, but devotees, including Geri Halliwell and Jennifer Aniston, swear it works.

Results: Average weight loss after one year: 4.6lbs; 53 per cent (21 of the 40 participants) completed the diet.

Weight Watchers

Calorie-controlled diet that works on a points system, allows followers to tot up how much damage their food that day will bring. Followers must endure the collective embarassment of attending weekly meetings and weighing themselves in on scales for all to see.

Results: Average weight loss after one year: 6.6lbs; 65 per cent (26 of 40) of participants completed.

Zone

The Zone program is based on consistent insulin control coupled withsupplementation of high-dose fish oil to modulate the synthesis of arachidonic acid.

Results: Average weight loss after one year: 7.1lbs; 65 per cent (26 out of 40) completed it.

Ornish

The Dean Ornish Eat More Weigh Less diet is a low-fat, mainly vegetarian diet plan. Only a few dairy products are allowed, such as fat-free yogurt, fat-free milk and lower-fat cheese.

Results: Average weight loss after one year: 7.3lbs; 50 per cent completed (20 of 40).