A randomized controlled trial comparing a virtual peer-led cognitive dissonance-based eating disorder prevention...

The Body Project: More than Muscles (MTM), a peer-led dissonance-based program for men with body dissatisfaction, has demonstrated efficacy in reducing eating disorder (ED) and muscle dysmorphia (MD) symptoms compared to assessment-only control through 1-month and 6-month follow-up when delivered in person. This study expands prior work in a larger, virtually delivered randomized controlled trial comparing MTM to a time-and-attention-matched control (media advocacy; MA). Between 2021 and 2024, n = 201 men with body image concerns, ages 18-30 were randomized to MTM (n = 100) or MA (n = 101) and completed clinical interviews at baseline and 6-month follow-up and self-reports at baseline, post-intervention, and 1-month and 6-month follow-up. Multilevel models examined differences between conditions over time. Retention across sessions was strong and did not differ across conditions (MTM=92%, MA=97%, p = .21). Self-reported acceptability was significantly better for MTM than MA (p = .001). Across conditions, there were significant decreases in ED and MD symptoms and risk factors over time. However, the only significant difference between conditions over time was for muscularity internalization, favoring MTM, at post-intervention. Within-condition effect sizes through follow-up ranged from small to moderate-large for MTM (d_RM=.22-.71) and small to moderate for MA (d_RM=.23-.58). Virtually delivered MTM is well-accepted by young men with body image concerns and preferred over MA; however, both interventions resulted in small-to-moderate ED and MD-related symptom improvements. Future research should investigate plausible moderators of outcome (e.g., symptom severity) that may indicate use of one program over the other.