Gender differences in adherence and retention in Mediterranean diet interventions with a weight-loss outcome: A systematic review and meta-analysis

BackgroundThe Mediterranean diet has been shown to be effective in improving health outcomes and for weight loss. Adherence and retention in dietary interventions are critical to ensure the benefits of the exposure. No studies to date have assessed the role of gender in understanding participants who remain engaged and adhere to Mediterranean diet interventions.AimsThis study aimed to explore gender differences in recruitment, adherence, and retention for Mediterranean diet interventions and whether these were associated with differences in weight-loss outcomes.MethodsA systematic search was completed in EMBASE, Medline, Cochrane, and from inception to March 2023. A meta-analysis of studies reporting retention by gender was completed using odds ratios comparing female to male dropout numbers. A second meta-analysis was completed for adherence comparing standardized mean difference of Mediterranean diet scores stratified by gender. Newcastle Ottawa score was used to assess risk of bias.ResultsA total of 70 articles were included in the systematic review with six articles included in the adherence meta-analysis and nine in the dropout meta-analysis. No statistically significant difference was shown for adherence or retention by gender. Weight-loss outcomes were inconsistent.ConclusionsThe results of the study suggest a higher adherence and lower dropout for women although these results were not statistically significant. Future studies of Mediterranean diet interventions should include adherence, retention, and weight-loss data stratified by gender to allow further investigation of this relationship.