Prevention of high body mass index and eating disorders: a systematic review and meta-analysis

Background: Eating disorders (EDs) and high body mass index (BMI) are two important public health issues with significant health and cost impacts. The aim of this systematic review and meta-analysis was to establish whether interventions are effective in preventing both issues. Methods: Electronic databases were searched up to 10 May 2021. Studies were included if they were randomised or quasi-randomised controlled trials that evaluated a preventive intervention (regardless of its aim to prevent ED, high BMI or both) and reported both EDs and BMI-related outcomes. Both narrative synthesis and meta-analysis were used to synthesise the results. Publication bias was also investigated. Results: Fifty-four studies were included for analysis. The primary aim of the studies was ED prevention (n = 23), high BMI prevention (n = 21) and both ED and high BMI prevention (n = 10). Meta-analysis results indicated that preventive interventions had a significant effect on several ED outcomes including dieting, shape and weight concerns, body dissatisfaction, negative affect, eating disorder symptoms and internalization, with effect sizes ranging from – 0.16 (95% CI – 0.27, – 0.06) to – 0.61 (95% CI – 0.29, – 0.04). Despite several studies that demonstrated positive impacts on BMI, there was no significant effect on BMI-related measures in the meta-analysis. The risk of publication bias was low for the majority of the pooled effect results. Conclusion: Preventive interventions were effective for either high BMI or EDs. However, there is limited evidence to show that current preventive interventions were effective in reducing both outcomes. Further research is necessary to explore the risk factors that are shared by these weight-related disorders as well as effective prevention interventions. Level of evidence: Level I: systematic review.