One downside of dieting is that it slows metabolism, making it harder to burn calories and continue losing weight. But focusing on ?good? carbohydrates rather than low-fat foods may curb the inevitable drop in metabolism that occurs when you cut back on calories.
In a Boston study, published in the November 2004 Journal of the American Medical Association, 39 overweight adults followed a diet that was either low in glycemic load, meaning the carbohydrates it contained were mostly those that do not cause a sharp rise in blood sugar, or was low in fat. Both groups consumed about 1,500 calories a day and both lost 10% of their body weight over 10 weeks.
As expected, the number of calories burned while resting decreased in both groups. However, the low-glycemic group saw their metabolism slow less than the low-fat group’s. (In effect, they burned 80 calories a day more.) Hunger was also less common in the low-glycemic group. Moreover, the low-glycemic dieters had greater improvements in risk factors for heart disease and diabetes, including insulin resistance, blood triglycerides and C-reactive protein?a marker for chronic inflammation (see article, this issue)’than the low-fat dieters.
The Bottom Line. Researchers have suggested before that changing the composition of diets so they contain fewer refined carbs that spike blood sugar levels and more low-glycemic (?good?) carbs, such as whole-wheat bread, oats, legumes and vegetables, is not only better for health, but also helps prevent metabolic slowdown when dieting. This small, preliminary study seems to confirm that.
Although this isn’t the last word on the topic, it makes sense that a diet with a low glycemic load that is moderate in fat and includes lots of vegetables, fruits, whole grains, beans and low-fat dairy is smart for your weight, as well as your overall health.