Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta-analysis | Lifestyle Behaviors | JAMA | JAMA Network
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Original Investigation
September 3, 2014

Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta-analysis

Author Affiliations
  • 1Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
  • 2Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada
  • 3Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
  • 4Department of Anesthesia and Pain Medicine, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
  • 5School of Population and Public Health, University of British Columbia, Vancouver, Canada
  • 6Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
  • 7Redwood Outcomes, Vancouver, British Columbia, Canada
  • 8Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
  • 9Department of Medicine, University of Toronto, Toronto, Ontario, Canada
  • 10Department of Pediatrics, University of Alberta, Edmonton, Canada
  • 11Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada
  • 12Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, Ontario, Canada
  • 13Department of Anesthesia, McMaster University, Hamilton, Ontario, Canada
  • 14Stanford Prevention Research Center, Stanford University School of Medicine, Stanford University, Stanford, California
  • 15Department of Public Health and Community Medicine, Tufts University, Boston, Massachusetts
JAMA. 2014;312(9):923-933. doi:10.1001/jama.2014.10397
Abstract

Importance  Many claims have been made regarding the superiority of one diet or another for inducing weight loss. Which diet is best remains unclear.

Objective  To determine weight loss outcomes for popular diets based on diet class (macronutrient composition) and named diet.

Data Sources  Search of 6 electronic databases: AMED, CDSR, CENTRAL, CINAHL, EMBASE, and MEDLINE from inception of each database to April 2014.

Study Selection  Overweight or obese adults (body mass index ≥25) randomized to a popular self-administered named diet and reporting weight or body mass index data at 3-month follow-up or longer.

Data Extraction and Synthesis  Two reviewers independently extracted data on populations, interventions, outcomes, risk of bias, and quality of evidence. A Bayesian framework was used to perform a series of random-effects network meta-analyses with meta-regression to estimate the relative effectiveness of diet classes and programs for change in weight and body mass index from baseline. Our analyses adjusted for behavioral support and exercise.

Main Outcomes and Measures  Weight loss and body mass index at 6- and 12-month follow-up (±3 months for both periods).

Results  Among 59 eligible articles reporting 48 unique randomized trials (including 7286 individuals) and compared with no diet, the largest weight loss was associated with low-carbohydrate diets (8.73 kg [95% credible interval {CI}, 7.27 to 10.20 kg] at 6-month follow-up and 7.25 kg [95% CI, 5.33 to 9.25 kg] at 12-month follow-up) and low-fat diets (7.99 kg [95% CI, 6.01 to 9.92 kg] at 6-month follow-up and 7.27 kg [95% CI, 5.26 to 9.34 kg] at 12-month follow-up). Weight loss differences between individual diets were minimal. For example, the Atkins diet resulted in a 1.71 kg greater weight loss than the Zone diet at 6-month follow-up. Between 6- and 12-month follow-up, the influence of behavioral support (3.23 kg [95% CI, 2.23 to 4.23 kg] at 6-month follow-up vs 1.08 kg [95% CI, −1.82 to 3.96 kg] at 12-month follow-up) and exercise (0.64 kg [95% CI, −0.35 to 1.66 kg] vs 2.13 kg [95% CI, 0.43 to 3.85 kg], respectively) on weight loss differed.

Conclusions and Relevance  Significant weight loss was observed with any low-carbohydrate or low-fat diet. Weight loss differences between individual named diets were small. This supports the practice of recommending any diet that a patient will adhere to in order to lose weight.

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