Malleability of weight-biased attitudes and beliefs: A meta-analysis of weight bias reduction interventions

• Weight bias exists across many important life domains and is associated with negative outcomes.
• This meta-analysis examined the effectiveness of weight bias interventions.
• A small to medium effect of interventions on weight-biased attitudes and beliefs was found.
• Planned moderators were not significant but revealed noteworthy trends.
• Further study is needed to determine which types of interventions are most effective.

Weight bias exists across many important life domains, necessitating interventions designed to reduce weight-biased attitudes and beliefs. Though the effectiveness of weight bias interventions has been questioned, to our knowledge no meta-analysis of these interventions has been conducted. This meta-analysis evaluated the impact of weight bias interventions on weight-biased attitudes and beliefs and explored potential moderators. Interventions were eligible if they used an adult sample and a validated measure of weight-biased attitudes, which resulted in the inclusion of 30 studies represented in 29 articles. A random effects approach using inverse weights resulted in a mean effect size estimate of g = −0.33 (lower scores indicate less weight bias) for both attitudes and beliefs. Intervention type, publication type, and population type were not significant moderators but demonstrated noteworthy trends. Results reveal a small, positive effect of weight bias interventions on weight-biased attitudes and beliefs and provide useful information for future interventions.