These days, supermarkets stock low-carb ice cream and low-carb bread. But there still isn't that much evidence to show that these low-carb diets work. Researchers in Florida, including Arthur Agatston—you may know him as the South Beach Diet guy —compared a low-carb diet with the higher-carb diet recommended by the U.S. National Cholesterol Education Program (NCEP) and the American Heart Association.

What the researchers wanted to know: Is a diet focused on protein, monounsaturated fat, and complex carbohydrates—with less total carbohydrates—better for weight loss than the NCEP diet, a low-calorie, lower-fat diet?

What they did: Sixty people with a body mass index of 27 or greater enrolled in the study. They were randomly assigned to follow one of the two diets for 12 weeks; they came in every two weeks for diet counseling and body measurements.

What they found: People on the modified low-carb diet lost an average of 13.6 pounds in 12 weeks, while people on the NCEP diet lost an average of only 7.5 pounds. There were no significant differences between the groups on waist-to-hip-ratio, total cholesterol, LDL cholesterol, HDL cholesterol, insulin, blood glucose, or C-reactive protein levels. However, the study was set up to look only for differences in weight; a variation in the design might have spotted other differences between the diets. The patients were equally happy with both diets and with their counseling, but more patients dropped out of the NCEP diet.

What the study means to you: In this short-term study with biweekly counseling visits, people on a modified low-carb diet lost more weight. But weight isn't the only thing that affects your heart disease risk. If you're thinking about those popular low-carb diets, note that this modified low-carb diet is low in saturated fats like those in bacon and butter; instead, it emphasizes protein and monounsaturated fats like those in olive oil and peanuts.

Caveats: The study lasted only 12 weeks. The long-term data on diets and health are pretty thin; low-carb diets could have unexpected effects in the long term. Also, this study mainly looked at weight loss, but other factors, such as cholesterol, may be just as important.

Find out more: A guide to the different kinds of fats: www.ces.ncsu.edu

Read the article: Aude, Y.W. et al. "The National Cholesterol Education Program Diet vs. a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat." Archives of Internal Medicine. Oct. 25, 2004, Vol. 164, pp. 2141–2146.

Abstract online: http://archinte.ama-assn.org