A randomized controlled trial of a dissonance-based eating disorder prevention intervention for body-dissatisfied Brazilian men: results from a 1-year follow-up.

Objective: To test the efficacy of a dissonance-based (DB) intervention in targeting risk factors for eating disorders (EDs) and predisposing factors for muscle dysmorphia (MD) symptoms in body-dissatisfied Brazilian men over 1 year of follow-up and evaluate whether reductions in body-ideal internalization would mediate the intervention's impact on ED and MD symptoms.

Methods: Participants were randomized to a two-session DB intervention (n=89) or assessment-only control (AOC) (n=91), and completed validated measures assessing body-ideal internalization, body dissatisfaction, ED, and MD symptoms at baseline, post-intervention, 1-month, 6-month, and 1-year follow-ups.

Results: The DB condition showed significantly greater reductions in MD symptoms and body dissatisfaction compared with the AOC group over a 1-year follow-up, while significant differences were not observed for body-ideal internalization and ED symptoms. Changes in body-ideal internalization from baseline to 1-month follow-up completely mediated the relationship between condition and the changes observed in both ED and MD symptoms.

Conclusion: These results provide further evidence of the efficacy of the tested intervention through 1-year follow-up in reducing body dissatisfaction and MD symptoms, but no such result was observed for body-ideal internalization and EDs. Our findings provide support for theoretical models of eating pathology and MD symptoms in Brazilian men.