People who followed a low-carbohydrate, high-protein diet lost more weight than people on a low-fat, low-cholesterol, low-calorie diet during a six-month comparison study at Duke University Medical Center (DUMC). However, the researchers caution that people with medical conditions such as diabetes and high blood pressure should not start the diet without close medical supervision.

“This diet can be quite powerful,” said lead researcher Will Yancy, MD, an assistant professor of medicine at Duke University Medical Center and a research associate at the Veterans Affairs Medical Center. “We found that the low-carb diet was more effective for weight loss,” Yancy added. “The weight loss surprised me, to be honest with you. We also found cholesterol levels seemed to improve more on a low-carb diet compared to a low-fat diet.”

The study is the first randomized, controlled trial of an Atkins-style diet approach, which includes vitamin and nutritional supplements. Along with losing an average of 26 pounds, dieters assigned to the low-carbohydrate plan lost more body fat, and lowered their triglyceride levels and raised their HDL, or good cholesterol, more than the low-fat dieters. The low-fat dieters lost an average of 14 pounds.

Though the low-fat diet group lowered their total cholesterol more than the low-carb dieters, the latter group nearly halved their triglycerides and their HDL jumped five points. The low-carbohydrate group reported more adverse physical effects, such as constipation and headaches, but fewer people dropped out of the low-carbohydrate diet than the low-fat diet.

The results appear in the May 18, 2004, issue of the Annals of Internal Medicine. The research was funded by an unrestricted grant from the Robert C. Atkins Foundation. The study authors have no financial interest in Atkins Nutritionals, Inc.

Despite the considerable weight loss experienced by the low-carbohydrate dieters, Yancy does not recommend an Atkins-style plan for patients attempting to lose weight for the first time.

“Over six months the diet appears relatively safe, but we need to study the safety for longer durations,” Yancy said. He also cautioned that the diet could present certain health risks, such as elevations in LDL cholesterol levels, bone loss, or kidney stones. This and other recent studies of the low-carbohydrate diet have not demonstrated that these health risks occur over short durations, but they might occur in people on the diet for long-term.

Others members of the Duke research team were Eric Westman, MD, Maren Olsen, PhD, John Guyton, MD, and Ronna Bakst, RD.