Premenopausal women who were assigned to follow the Atkins diet for one year lost more weight when compared to women who were assigned to follow the Zone, Ornish and LEARN diets, according to a study in the March 7 issue of JAMA.

Overweight and obesity are well-documented problems in the United States. National dietary weight loss guidelines (a diet low in calories and fat, high in carbohydrates) have been challenged, particularly by supporters of low-carbohydrate diets. However, limited evidence has been available to effectively evaluate other diets, according to background information in the article.

Christopher D. Gardner, Ph.D., of Stanford University Medical School, Stanford, Calif., and colleagues examined the effects of four diets-3 popular and substantially different diets and 1 diet based on national guidelines-representing a spectrum of carbohydrate intake, on weight loss and related metabolic variables in overweight and obese premenopausal women. The diets were Atkins (very low in carbohydrate), Zone (low in carbohydrate), LEARN (Lifestyle, Exercise, Attitudes, Relationships, and Nutrition; low in fat, high in carbohydrate, based on national guidelines), and Ornish (high in carbohydrate). The study, which included 311 overweight/obese (body mass index, 27-40) nondiabetic, premenopausal women, was conducted from February 2003 to October 2005. Participants were randomly assigned to follow for 12 months the Atkins (n = 77), Zone (n = 79), LEARN (n = 79), or Ornish (n = 76) diets and received weekly instruction for 2 months, then an additional 10-month follow-up.

Besides weight loss, the participants were also measured for lipid profile (low-density lipoprotein, high-density lipoprotein, and non-high-density lipoprotein cholesterol, and triglyceride levels), percentage of body fat, waist-hip ratio, fasting insulin and glucose levels, and blood pressure. Outcomes were assessed at months 0, 2, 6, and 12.

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JAMA and Archives Journals
6-Mar-2007