Welk dieet?
Dat is wat enkele wetenschappers zich afvroegen. Ze onderzochten enkele bekende diëten. De 160 deelnemers aan het onderzoek mochten kiezen tussen Atkins, Ornish, Weight Watchers en the Zone. Van de mensen die het dieet volhielden liepen de resultaten niet ver uiteen. Mensen die het Ornish dieet volgden waren na een jaar 6% afgevallen, de mensen die Weight Watchers en de Zone deden 5% en de Atkinsers 4%. Bij het verlagen van het risico op hartaandoeningen scoorde Weight Watchers het beste (15%) en Ornish het slechtst (7%). De overige twee dieten scoorden 12%. Overigens hield een derde tot de helft van de deelnemers het dieet niet vol.

Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight Loss and Heart Disease Risk Reduction

A Randomized Trial

Michael L. Dansinger, MD; Joi Augustin Gleason, MS, RD; John L. Griffith, PhD; Harry P. Selker, MD, MSPH; Ernst J. Schaefer, MD

JAMA. 2005;293:43-53.

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 reduction.

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, respectively).

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.

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.  (Februari 2006)