Low-Glycemic Index Diet Best For Weight-Loss Management

BOSTONA low-glycemic index diet that reduces refined carbohydrates may help maintain weight loss better than reducing fat, according to a new study published in the Journal of American Medical Association (JAMA) that challenges the notion that "a calorie is a calorie."

The findings revealed diets that reduce the surge in blood sugar after a mealeither low-glycemic index or very low-carbohydratemay be preferable to a low-fat diet for those trying to achieve lasting weight loss. Results also showed the low-glycemic index diet had similar metabolic benefits to the very low-carb diet without negative effects of stress and inflammation as seen by participants consuming the very low-carb diet.

Researchers at the New Balance Foundation Obesity Prevention Center Boston Children's Hospital investigated three popular dietslow-carb, low-glycemic and low-fatto see if certain diets might lead to metabolic changes that could make it harder for dieters to maintain weight loss.

For the study, 21 overweight and obese young adults aged 18 to 40 first had to lose 10% to 15% of their body weight, and after weight stabilization, completed all three of the following diets in random order, each for four weeks at a time. The randomized crossover design allowed for rigorous observation of how each diet affected all participants, regardless of the order in which they were consumed. The low-fat diet derived 60% of its calories from carbohydrates, 20% from fat and 20% from protein. The low-glycemic index diet contained 40% carbohydrates, 40% fat and 20% protein. The low-carbohydrate diet contained 60% fat, 30% protein and 10% carbohydrates.

Each of the three diets fell within the normal healthy range of 10% to 35% of daily calories from protein. They found the low-glycemic load diet was more effective than conventional approaches at burning calories (and keeping energy expenditure) at a higher rate after weight loss. The very low-carbohydrate diet produced the greatest improvements in metabolism, but increased participants cortisol levels, which can lead to insulin resistance and cardiovascular disease. The very low-carbohydrate diet also raised C-reactive protein levels, which may also increase risk of cardiovascular disease. The low-fat diet caused the greatest decrease in energy expenditure, an unhealthy lipid pattern and insulin resistance.

In addition to the benefits noted in this study, we believe that low-glycemic index diets are easier to stick to on a day-to-day basis, compared to low-carb and low-fat diets, which many people find limiting," the researchers said. Unlike low-fat and very low-carbohydrate diets, a low-glycemic index diet doesnt eliminate entire classes of food, likely making it easier to follow and more sustainable."