Low glycemic index diets work in rodents

27 August 2004

A report appearing in the August 28 2004 issue of The Lancet detailed experiments conducted by David Ludwig MD and colleagues of the Optimal Weight for Life obesity program at Children's Hospital in Boston which found that rats provided with a low-glycemic index diet experienced greater body fat loss and a reduction in cardiovascular disease and diabetes risk factors compared to rats who consumed a high-glycemic diet. The glycemic index of a food rates the rapidity with which it releases sugar into the bloodstream. The consumption of low as opposed to high glycemic index foods may be helpful when for weight loss and the treatment of diabetes.

In the first study, eleven rats were given a high-glycemic index diet, and ten rats received a low-glycemic index diet. After eighteen weeks, rats who received the low-glycemic index diets had a 71 percent greater amount of body fat, 8 percent lower amount of lean body mass, and a greater amount of fat in the trunk area (correlated with elevated cardiovascular disease risk) than the high-glycemic index group. Low-glycemic index fed rats also had reduced glucose, insulin and triglyceride levels.

In a second experiment, fourteen rats were fed high or low glycemic index diets for seven weeks, after which each group of rats received the diet that the other group received during the first part of the experiment. Rats changed from the low to high glycemic diet had greater elevations in glucose and insulin than those switched from the high to low-glycemic diet.

And in an experiment involving twenty mice fed high or low-glycemic index diets for nine weeks, the high- glycemic index diet was associated with a 93 percent increase in body fat compared with the low-glycemic index group.