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Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM. Prevalence of overweight and obesity in the United States, 1999-2004.  JAMA. 2006;295:1549-155516595758Google ScholarCrossref
Finkelstein EA, Ruhm CJ, Kosa KM. Economic causes and consequences of obesity.  Annu Rev Public Health. 2005;26:239-25715760288Google ScholarCrossref
Appel LJ, Champagne CM, Harsha DW.  et al.  Effects of comprehensive lifestyle modification on blood pressure control: main results of the PREMIER clinical trial.  JAMA. 2003;289:2083-209312709466Google ScholarCrossref
Knowler WC, Barrett-Connor E, Fowler SE.  et al.  Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.  N Engl J Med. 2002;346:393-40311832527Google ScholarCrossref
Pan XR, Li GW, Hu YH.  et al.  Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance: the Da Qing IGT and Diabetes Study.  Diabetes Care. 1997;20:537-5449096977Google ScholarCrossref
Stevens VJ, Obarzanek E, Cook NR.  et al.  Long-term weight loss and changes in blood pressure: results of the Trials of Hypertension Prevention, phase II.  Ann Intern Med. 2001;134:1-1111187414Google ScholarCrossref
 Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults—the Evidence Report: National Institutes of Health.  Obes Res. 1998;6:(suppl 2)  51S-209S9813653Google ScholarCrossref
Atkins R. Dr Atkins' New Diet Revolution. New York, NY: Harper Collins; 2002
Sears B, Lawren W. Enter the Zone. New York, NY: Harper Collins; 1995
Bravata DM, Sanders L, Huang J.  et al.  Efficacy and safety of low-carbohydrate diets: a systematic review.  JAMA. 2003;289:1837-185012684364Google ScholarCrossref
Freedman MR, King J, Kennedy E. Popular diets: a scientific review.  Obes Res. 2001;9:(suppl)  1S-40S11374180Google ScholarCrossref
Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women.  J Clin Endocrinol Metab. 2003;88:1617-162312679447Google ScholarCrossref
Foster GD, Wyatt HR, Hill JO.  et al.  A randomized trial of a low-carbohydrate diet for obesity.  N Engl J Med. 2003;348:2082-209012761365Google ScholarCrossref
Stern L, Iqbal N, Seshadri P.  et al.  The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial.  Ann Intern Med. 2004;140:778-78515148064Google ScholarCrossref
Yancy WS Jr, Olsen MK, Guyton JR, Bakst RP, Westman EC. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial.  Ann Intern Med. 2004;140:769-77715148063Google ScholarCrossref
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;293:43-5315632335Google ScholarCrossref
Nordmann AJ, Nordmann A, Briel M.  et al.  Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: a meta-analysis of randomized controlled trials.  Arch Intern Med. 2006;166:285-29316476868Google ScholarCrossref
Brownell KD. The LEARN Manual for Weight Management. Dallas, Tex: American Health Publishing Co; 2000
Ornish D. Eat More, Weigh Less. New York, NY: Harper Collins; 2001
Sallis JF, Haskell WL, Wood PD.  et al.  Physical activity assessment methodology in the Five-City Project.  Am J Epidemiol. 1985;121:91-1063964995Google Scholar
American College of Sports Medicine.  Physical Fitness Testing and Interpretation. Philadelphia, Pa: Williams & Wilkins; 2000
Allain CC, Poon LS, Chan CS, Richmond W, Fu PC. Enzymatic determination of total serum cholesterol.  Clin Chem. 1974;20:470-4754818200Google Scholar
Sampson EJ, Demers LM, Krieg AF. Faster enzymatic procedure for serum triglycerides.  Clin Chem. 1975;21:1983-19851192594Google Scholar
Warnick GR, Albers JJ. A comprehensive evaluation of the heparin-manganese precipitation procedure for estimating high density lipoprotein cholesterol.  J Lipid Res. 1978;19:65-76202660Google Scholar
Friedewald WT, Levy R, Fredrickson D. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, with use of the preparative ultracentrifuge.  Clin Chem. 1972;18:499-5024337382Google Scholar
Gardner CD, Winkleby MA, Fortmann SP. Population frequency distribution of non-high-density lipoprotein cholesterol (Third National Health and Nutrition Examination Survey [NHANES III], 1988-1994).  Am J Cardiol. 2000;86:299-30410922437Google ScholarCrossref
Morgan CR, Lazarow A. Immunoassay of insulin: two antibody system: plasma insulin levels in normal, sub diabetic, and diabetic rats.  Diabetes. 1963;12:115Google Scholar
Trinder P. Determination of blood glucose using an oxidase-peroxidase system with a non-carcinogenic chromogen.  J Clin Pathol. 1969;22:158-1615776547Google ScholarCrossref
Lott JA, Turner K. Evaluation of Trinder's glucose oxidase method for measuring glucose in serum and urine.  Clin Chem. 1975;21:1754-17601237363Google Scholar
King AC, Sallis JF, Dunn AL.  et al.  Overview of the Activity Counseling Trial (ACT) intervention for promoting physical activity in primary health care settings.  Med Sci Sports Exerc. 1998;30:1086-10969662678Google ScholarCrossref
Wood PD, Stefanick ML, Dreon DM.  et al.  Changes in plasma lipids and lipoproteins in overweight men during weight loss through dieting as compared with exercise.  N Engl J Med. 1988;319:1173-11793173455Google ScholarCrossref
Wood PD, Stefanick ML, Williams PT, Haskell WL. The effects on plasma lipoproteins of a prudent weight-reducing diet, with or without exercise, in overweight men and women.  N Engl J Med. 1991;325:461-4661852180Google ScholarCrossref
National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III).  Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report.  Circulation. 2002;106:3143-342112485966Google Scholar
Blackburn GL, Phillips JC, Morreale S. Physician's guide to popular low-carbohydrate weight-loss diets.  Cleve Clin J Med. 2001;68:761, 765-766, 768-769, 773-77411563479Google ScholarCrossref
Connor WE, Connor SL. Should a low-fat, high-carbohydrate diet be recommended for everyone? the case for a low-fat, high-carbohydrate diet.  N Engl J Med. 1997;337:562-5639262503Google ScholarCrossref
Katan MB, Grundy SM, Willett WC. Should a low-fat, high-carbohydrate diet be recommended for everyone? beyond low-fat diets.  N Engl J Med. 1997;337:563-5669262504Google Scholar
Berneis KK, Krauss RM. Metabolic origins and clinical significance of LDL heterogeneity.  J Lipid Res. 2002;43:1363-137912235168Google ScholarCrossref
Krauss RM, Blanche PJ, Rawlings RS, Fernstrom HS, Williams PT. Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia.  Am J Clin Nutr. 2006;83:1025-103116685042Google Scholar
Gardner CD, Fortmann SP, Krauss RM. Association of small low-density lipoprotein particles with the incidence of coronary artery disease in men and women.  JAMA. 1996;276:875-8818782636Google ScholarCrossref
Luscombe-Marsh ND, Noakes M, Wittert GA, Keogh JB, Foster P, Clifton PM. Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids.  Am J Clin Nutr. 2005;81:762-77215817850Google Scholar
Weigle DS, Breen PA, Matthys CC.  et al.  A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite c ompensatory changes in diurnal plasma leptin and ghrelin concentrations.  Am J Clin Nutr. 2005;82:41-4816002798Google Scholar
Farnsworth E, Luscombe ND, Noakes M, Wittert G, Argyiou E, Clifton PM. Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women.  Am J Clin Nutr. 2003;78:31-3912816768Google Scholar
Noakes M, Keogh JB, Foster PR, Clifton PM. Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women.  Am J Clin Nutr. 2005;81:1298-130615941879Google Scholar
Appel LJ, Sacks FM, Carey VJ.  et al.  Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial.  JAMA. 2005;294:2455-246416287956Google ScholarCrossref
Hill JO, Wyatt HR, Reed GW, Peters JC. Obesity and the environment: where do we go from here?  Science. 2003;299:853-85512574618Google ScholarCrossref
Kim S, Popkin BM. Understanding the epidemiology of overweight and obesity—a real global public health concern.  Int J Epidemiol. 2006;35:60-6716339598Google ScholarCrossref
Drewnowski A. Obesity and the food environment: dietary energy density and diet costs.  Am J Prev Med. 2004;27:(suppl)  154-16215450626Google ScholarCrossref
Ello-Martin JA, Ledikwe JH, Rolls BJ. The influence of food portion size and energy density on energy intake: implications for weight management.  Am J Clin Nutr. 2005;82:(suppl)  236S-241S16002828Google Scholar
Foster GD, Makris AP, Bailer BA. Behavioral treatment of obesity.  Am J Clin Nutr. 2005;82:(suppl)  230S-235S16002827Google Scholar
Original Contribution
March 7, 2007

Comparison of the Atkins, Zone, Ornish, and LEARN Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women: The A TO Z Weight Loss Study: A Randomized Trial

Author Affiliations

Author Affiliations: Stanford Prevention Research Center and the Department of Medicine, Stanford University Medical School, Stanford, Calif.

JAMA. 2007;297(9):969-977. doi:10.1001/jama.297.9.969

Context Popular diets, particularly those low in carbohydrates, have challenged current recommendations advising a low-fat, high-carbohydrate diet for weight loss. Potential benefits and risks have not been tested adequately.

Objective To compare 4 weight-loss diets representing a spectrum of low to high carbohydrate intake for effects on weight loss and related metabolic variables.

Design, Setting, and Participants Twelve-month randomized trial conducted in the United States from February 2003 to October 2005 among 311 free-living, overweight/obese (body mass index, 27-40) nondiabetic, premenopausal women.

Intervention Participants were randomly assigned to follow 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.

Main Outcome Measures Weight loss at 12 months was the primary outcome. Secondary outcomes included 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. The Tukey studentized range test was used to adjust for multiple testing.

Results Weight loss was greater for women in the Atkins diet group compared with the other diet groups at 12 months, and mean 12-month weight loss was significantly different between the Atkins and Zone diets (P<.05). Mean 12-month weight loss was as follows: Atkins, −4.7 kg (95% confidence interval [CI], −6.3 to −3.1 kg), Zone, −1.6 kg (95% CI, −2.8 to −0.4 kg), LEARN, −2.6 kg (−3.8 to −1.3 kg), and Ornish, −2.2 kg (−3.6 to −0.8 kg). Weight loss was not statistically different among the Zone, LEARN, and Ornish groups. At 12 months, secondary outcomes for the Atkins group were comparable with or more favorable than the other diet groups.

Conclusions In this study, premenopausal overweight and obese women assigned to follow the Atkins diet, which had the lowest carbohydrate intake, lost more weight and experienced more favorable overall metabolic effects at 12 months than women assigned to follow the Zone, Ornish, or LEARN diets. While questions remain about long-term effects and mechanisms, a low-carbohydrate, high-protein, high-fat diet may be considered a feasible alternative recommendation for weight loss.

Trial Registration clinicaltrials.gov Identifier: NCT00079573