Public release date: 2-Aug-2010

– low-carbohydrate diet produced a greater increase in plasma HDL cholesterol concentration than did the low-fat diet at all assessments points during the two-year study.

Previous studies comparing low-carbohydrate and low-fat diets have not included comprehensive behavioral treatment. Researchers sought to evaluate the long-term effects of a low-carbohydrate versus a low-fat diet when combined with a comprehensive lifestyle modification program. Three hundred and seven patients were randomly assigned to either a low-carbohydrate (n=153) or low-fat (n=154) diet with behavior treatment. Weight at two years was the primary outcome, but other effects were measured throughout the study period. At three, six, and 12 months, patients were evaluated for weight, serum lipid concentrations, blood pressure, urinary ketones, bone mineral density, and body composition. The researchers found no differences in weight, body composition, or bone mineral density between the two groups at any point during the study. At two years, both groups had lost a clinically significant amount of weight (about 7 percent of body weight), showing that successful weight loss can be achieved with either approach when coupled with a behavioral modification program. However, the low-carbohydrate diet produced a greater increase in plasma HDL cholesterol concentration than did the low-fat diet at all assessments points during the two-year study.