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Dansinger ML, Gleason JA, Griffith JL, Selker HP, Schaefer EJ. Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Risk Reduction: A Randomized Trial. JAMA. 2005;293(1):43–53. doi:10.1001/jama.293.1.43
Author Affiliations: Division of Endocrinology,
Diabetes, and Metabolism (Drs Dansinger and Schaefer), and Institute for Clinical
Research and Health Policy Studies (Drs Griffith and Selker), Tufts-New England
Medical Center; and Lipid Metabolism Laboratory, Jean Mayer US Department
of Agriculture Human Nutrition Research Center on Aging, Tufts University
(Dr Schaefer and Ms Gleason), Boston, Mass.
Context The scarcity of data addressing the health effects of popular diets
is an important public health concern, especially since patients and physicians
are interested in using popular diets as individualized eating strategies
for disease prevention.
Objective To assess adherence rates and the effectiveness of 4 popular diets (Atkins,
Zone, Weight Watchers, and Ornish) for weight loss and cardiac risk factor
Design, Setting, and Participants A single-center randomized trial at an academic medical center in Boston,
Mass, of overweight or obese (body mass index: mean, 35; range, 27-42) adults
aged 22 to 72 years with known hypertension, dyslipidemia, or fasting hyperglycemia.
Participants were enrolled starting July 18, 2000, and randomized to 4 popular
diet groups until January 24, 2002.
Intervention A total of 160 participants were randomly assigned to either Atkins
(carbohydrate restriction, n=40), Zone (macronutrient balance, n=40), Weight
Watchers (calorie restriction, n=40), or Ornish (fat restriction, n=40) diet
groups. After 2 months of maximum effort, participants selected their own
levels of dietary adherence.
Main Outcome Measures One-year changes in baseline weight and cardiac risk factors, and self-selected
dietary adherence rates per self-report.
Results Assuming no change from baseline for participants who discontinued the
study, mean (SD) weight loss at 1 year was 2.1 (4.8) kg for Atkins (21 [53%]
of 40 participants completed, P = .009),
3.2 (6.0) kg for Zone (26 [65%] of 40 completed, P = .002),
3.0 (4.9) kg for Weight Watchers (26 [65%] of 40 completed, P < .001), and 3.3 (7.3) kg for Ornish (20 [50%] of 40
completed, P = .007). Greater effects were
observed in study completers. Each diet significantly reduced the low-density
lipoprotein/high-density lipoprotein (HDL) cholesterol ratio by approximately
10% (all P<.05), with no significant effects on
blood pressure or glucose at 1 year. Amount of weight loss was associated
with self-reported dietary adherence level (r = 0.60; P<.001) but not with diet type (r = 0.07; P = .40). For
each diet, decreasing levels of total/HDL cholesterol, C-reactive protein,
and insulin were significantly associated with weight loss (mean r = 0.36, 0.37, and 0.39, respectively) with no significant
difference between diets (P = .48, P = .57, P = .31,
Conclusions Each popular diet modestly reduced body weight and several cardiac risk
factors at 1 year. Overall dietary adherence rates were low, although increased
adherence was associated with greater weight loss and cardiac risk factor
reductions for each diet group.
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