Rigorous control conditions diminish treatment effects in weight loss-randomized controlled trials.

Academic Article


  • BACKGROUND: It has not been established whether control conditions with large weight losses (WLs) diminish expected treatment effects in WL or prevention of weight gain (PWG)-randomized controlled trials (RCTs). SUBJECTS/METHODS: We performed a meta-analysis of 239 WL/PWG RCTs that include a control group and at least one treatment group. A maximum likelihood meta-analysis framework was used to model and understand the relationship between treatment effects and control group outcomes. RESULTS: Under the informed model, an increase in control group WL of 1 kg corresponds with an expected shrinkage of the treatment effect by 0.309 kg (95% confidence interval (-0.480, -0.138), P=0.00081); this result is robust against violations of the model assumptions. CONCLUSIONS: We find that control conditions with large WLs diminish expected treatment effects. Our investigation may be helpful to clinicians as they design future WL/PWG studies.
  • Published In


  • Humans, Obesity, Randomized Controlled Trials as Topic, Treatment Outcome, Weight Loss, Weight Reduction Programs
  • Digital Object Identifier (doi)

    Author List

  • Dawson JA; Kaiser KA; Affuso O; Cutter GR; Allison DB
  • Start Page

  • 895
  • End Page

  • 898
  • Volume

  • 40
  • Issue

  • 6