Exploring the moderating effect of body mass index on the association between physical appearance comparisons and the symptoms of muscle dysmorphic disorder

Muscle dysmorphic disorder (MDD) is a subtype of body dysmorphic disorder primarily affecting adolescent boys and men. While physical appearance comparisons are known to intensify MDD symptoms, the moderating role of body mass index (BMI) in these associations remains insufficiently studied. This research investigates BMI as a moderator in the relationship between physical appearance comparisons and MDD core dimensions: drive for size, appearance intolerance, and functional impairment. Data from 968 Israeli men were collected using structured online questionnaires. The findings revealed more pronounced associations between physical appearance comparison and drive for size, and between physical appearance comparison and functional impairment, at lower BMI levels. However, the association between physical appearance comparison and appearance intolerance was more pronounced at higher BMI levels. These results could inform the development of therapeutic interventions to help professionals address MDD symptoms and guide policies and programs targeting MDD risk factors.