Easy Atkins may be the best way to diet

Published on Friday 27 August 2004 00:56

EATING vegetables, fruit, nuts and beans instead of white bread and sugary breakfast cereals could be the ultimate way to diet, new research reveals.

An animal study provided such clear evidence of the health benefits of avoiding the "wrong" kind of carbohydrates that scientists are now recruiting volunteers for a large-scale human trial. The research showed that the "Atkins alternative" can lead to weight loss, reduced body fat, and reduced risk factors for diabetes and heart disease.

The traditional Atkins diet seeks to minimise consumption of all kinds of carbohydrates.

But the low glycaemic index (low-GI) diet distinguishes between "good" and "bad" carbs.

Foods with a low glycaemic index are low in sugar, or release sugar slowly.

High-GI carbohydrates, such as white bread, refined breakfast cereals and concentrated sugars, are rapidly digested and cause a surge of blood glucose and insulin.

Low-GI carbohydrates release their sugar more slowly and avoid the glucose and insulin "spike". They include whole grains, most fruits, vegetables, nuts and beans.

Previous studies have indicated that low-GI diets are beneficial, but it has not been clear whether the effects are due to other aspects of diet such as fibre or overall calorie intake.

In the new study, rats were fed tightly controlled diets with identical nutrients, except for the type of carbohydrate starch. Both groups of animals were given diets composed of 69 per cent carbohydrates. But 11 rats were randomly assigned to high-GI starch and 10 to low-GI starch. Food portions were strictly controlled to maintain the same average body weight in the two groups.

After 18 weeks the high-GI group had 71 per cent more body fat and 8 per cent less lean body mass than the low-GI group, despite similar body weights. The fat in the high-GI group was concentrated in the trunk. Fat around the middle of the body produces the "apple" shape in humans that is a risk factor for heart disease.

Tests showed changes in glucose tolerance and pancreatic cells in the high-GI group which occur in diabetes. High-GI rats also had levels of triglyceride blood fats nearly three times higher than the low-GI group. High triglyceride levels are a recognised risk factor for heart disease in humans.

The results from the American study are published today in the Lancet medical journal.

Dr David Ludwig, who led the team at the Children’s Hospital in Boston, said: "The study findings should give impetus to large-scale trials of low-GI diets in humans.

"What the study shows is that glycaemic index is an independent factor that can have dramatic effects on the major chronic diseases plaguing developed nations - obesity, diabetes and heart disease.

"The Atkins diet tries to get rid of all carbohydrates, which we think is excessively restrictive. You don’t have to go to this extreme if you pay attention to the glycaemic index."

The human trial planned by Dr Ludwig will put overweight volunteers on a low-GI diet and observe them for 18 months.