Popular diets have become increasingly prevalent and controversial, according to background information in the article. Many popular plans depart substantially from mainstream medical advice, and the effectiveness and safety of these diets have been questioned. Data regarding the relative benefits, risks, effectiveness, and sustainability of popular diets have been limited.
In this one year study, Michael L. Dansinger, M.D., of Tufts-New England Medical Center, Boston, and colleagues assessed adherence rates and the effectiveness of four popular diets for weight loss and cardiac risk factor reduction. The diets and their principle weight loss strategies were: Weight Watchers (restriction of portion sizes and calories); Atkins (minimize carbohydrate intake without fat restriction); Zone (modulate macronutrient balance and glycemic load); and Ornish (restrict fat).
This trial included 160 overweight or obese adults aged 22 to 72 years, with known hypertension, dyslipidemia (high cholesterol), or fasting hyperglycemia (high blood sugar). Participants were enrolled starting July 18, 2000, and randomized to the diet groups until January 24, 2002. Forty participants were assigned to each of the diet plans. After 2 months of maximum effort, participants selected their own levels of dietary adherence.
Assuming no change from baseline for participants who discontinued the study, the researchers found that average weight loss at 1 year was 4.6 lbs. for Atkins (21 [53 percent] of 40 participants completed), 7.1 lbs. for Zone (26 [65 percent] of 40 completed), 6.6 lbs. for W
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