In an analysis of six clinical trials, Australian researchers found that diets based on the glycemic index were generally effective at helping overweight and obese adults lose weight in the short term. What's more, these low-glycemic index diets seemed to work somewhat better than traditional calorie- and fat-conscious weight-loss plans.

Glycemic index refers to the effects a particular food has on blood sugar levels. High-glycemic index foods, like white bread and potatoes, tend to spur a quick surge in blood sugar, and some studies have suggested that diets heavy in such foods can contribute to weight gain, diabetes and heart disease.

Low glycemic index foods, such as lentils, soybeans, yogurt and many high-fiber grains, create a slower increase in blood sugar and, therefore, a more gradual release of insulin, a hormone that regulates blood sugar.

The difference between the two types of diets included in the current review was far from dramatic; on average, low-glycemic index dieters lost about 2 pounds more.

Low-glycemic index diets might be more palatable for many people, which may contribute to the difference in weight loss between the two types of diets, according to the review authors.

"It may be easier to adhere to a (low-glycemic index) diet than a conventional weight loss diet, since there is less need to restrict the intake of food so long as the carbohydrates consumed have a low (glycemic index)," lead study author Dr. Diana E. Thomas, of the University of Sydney and Children's Hospital at Westmead, added in a statement.

She and her colleagues report the findings in the Cochrane Library, an online journal published by the Cochrane Collaboration, an international research organization.

The six trials included in the review involved a total of 202 overweight or obese men and women; participants followed either a low-glycemic index diet or a comparison plan for anywhere from 5 weeks to 6 months, and their weight was tracked for up to 6 months afterward.

In some of these trials, people on low-glycemic index diets were allowed to eat all the low-glycemic index food they wanted. In general, the review found, these dieters did as well or better than those who followed a traditional calorie-restricted plan.

A major remaining question is how well low-glycemic index diets work in the long term, according to Thomas's team.

But for the short term, the researchers conclude, cutting high-glycemic index foods from the diet "appears to be an effective method of losing weight, particularly for the obese."

SOURCE: Cochrane Library, July 18, 2007, online.