Effect of a healthy body image intervention on risk- and protective factors for eating disorders: A cluster randomized controlled trial

To investigate the immediate and 12-months effects of a school-based intervention aiming to reduce risk enhance protective factors for eating disorder development in high school boys girls. In total, 4,149 adolescents from 30 schools were eligible inclusion 2,446 consented participate randomly allocated Healthy Body Image (HBI) or control group (classes as usual). The HBI is multicomponent consisting three workshops targeting body image, social media usage lifestyle. Linear mixed model intention-to-treat analyses applied group, time, gender at posttest, 3-, follow-up. main outcome variable was sympomatology, secondary variables self-esteem, mental distress, image flexibility, thin internalization, muscular drive leanness, perceived pressure, protein- creatine supplement use, diet aid use. significantly reduced factor scores related internalization pressure media, which particularly pronounced Positive on flexibility only observed posttest but grew increasingly larger girls across 12-month follow-up time span. Favorable protein use present 3-months solely. A general favorable effect leanness. produced consistent reductions enhancements associated with adolescents.