At Two Years, Low-carb Diet Beats Low-Fat for HDL-Cholesterol Levels

“Despite the conventional wisdom that a low-carbohydrate diet would actually make cardiovascular risk factors worse, it appears that across a lot of risk factors including blood pressure and lipid profiles, that a low-carbohydrate diet was associated with significant improvements,” said study lead author Gary Foster, PhD, director of the Center for Obesity Research and Education at Temple University, Philadelphia.

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. However, dieters in the low-carbohydrate group had double the increase of good cholesterol levels over the low-fat group (23 percent versus 11 percent, respectively) at two years.

“I think an important outcome from a study like this is to think about which diets fit best for which people,” said Foster. “This study would suggest that perhaps for those with low HDL-cholesterol levels to begin with, that a low-carbohydrate approach to weigh loss may have some advantages.”

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.

“At the end of the day, behavior interventions are key,” said Foster “Dieters should be less concerned about what diet they follow, and more concerned with employing effective behavioral strategies, such as recording what they eat, logging their exercise, and limiting the triggers for overeating, like watching TV or eating in the car.”

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