A randomized controlled trial to evaluate the acceptability and effectiveness of two eating disorders prevention interventions: the HEIDI BP-HW project.

Background: Eating disorders (ED) are common in Switzerland, as in other Western countries, with a prevalence of any ED of 3.5%. However, no specific prevention intervention has been evaluated in the French-speaking part of the country. In this study, we assessed the acceptability and effectiveness of two well-validated eating disorders prevention interventions: the Body Project intervention (BP), based on cognitive dissonance techniques, and the Healthy Weight intervention (HW), based on the implementation of a healthy lifestyle.

Methods: Forty female students, aged 18-28, with body dissatisfaction, were randomized into three arms: a BP group, an HW group, and a waiting-list control group (WLCG). The primary outcome measure was body dissatisfaction. Secondary outcomes were thin-ideal internalization, dietary restraint, negative affect, and ED psychopathology. Thirty-three participants completed the assessments before and after the one-month interventions or waiting period. A follow-up measurement was conducted one month after the interventions to assess the stability of the results.

Results: Both interventions, delivered via a virtual web platform, were considered acceptable. The reduction in body dissatisfaction was greater in the BP group (r = 0.7; p < 0.01) or the HW group (r = 0.6; p < 0.01) than in the WLCG, with large effect sizes. Dietary restraint and shape concern were also significantly reduced in the BP group (r = 0.6 and r = 0.7, respectively; p < 0.01) and HW group (r = 0.5 and r = 0.5, respectively; p < 0.05) compared to the WLCG, with moderate to large effect sizes. The results obtained in each intervention group were stable at the one-month follow-up.

Conclusions: This study showed encouraging results in young women with body dissatisfaction, arguing in favor of the French adaptations of the BP and HW interventions. However, the feasibility of recruitment was difficult, partly due to the pandemic situation at the time of the study, and should be further considered to improve dissemination.

Trial Registration: ClinicalTrials.gov Identifier: NCT04558073, 22/09/2020 and Swiss National Clinical Trial Portal (SNCTP000003978).