Not long ago, low-carbohydrate diets were all the rage, despite little scientific evidence to back up their reputed health benefits or the much ballyhooed stories of weight loss. Researchers recently compared low-carb diets to low-fat diets to determine which were more successful in reducing cardiovascular disease (CVD) risk and inducing long-term weight loss. The findings of this meta-analysis of randomized clinical trials were reported in the February 13, 2006, issue of the Archives of Internal Medicine.

In reviewing the results of five salient clinical trials, the researchers determined that after 6 months, low-carb dieters had lost more weight than study participants on a low-fat diet. As for CVD risk factors, triglyceride and HDL cholesterol levels changed more favorably in the low-carb group during those first 6 months, whereas total cholesterol and LDL cholesterol changed more favorably in individuals assigned to low-fat diets. However, after 12 months, the low-carb dieters and low-fat dieters had similar results in terms of weight loss and CVD risk factors.

“Low-carbohydrate, non-energy-restricted diets appear to be at least as effective as energy-restricted diets in inducing weight loss for up to 1 year,” the researchers concluded. “However, potential favorable changes to triglyceride and high-density lipoprotein cholesterol values should be weighed against potential unfavorable changes in low-density lipoprotein cholesterol values when low-carbohydrate diets to induce weight loss are considered.”