Muscularity bias internalization moderates the associations of muscularity dissatisfaction with muscularity-oriented disordered eating and psychosocial well-being in men but not women.

Prior research demonstrates positive associations between muscularity dissatisfaction and an array of negative health outcomes, including muscularity-oriented disordered eating, eating-related psychosocial impairment, and psychological distress. However, muscularity dissatisfaction differs by gender and is not always linked to these outcomes, indicating the existence of moderators of these associations. We proposed and examined muscularity bias internalization (MBI) as a moderator of these associations. The study included online samples of 450 Chinese men and 450 Chinese women who completed measures assessing MBI, muscularity dissatisfaction, muscularity-oriented disordered eating, eating-related psychosocial impairment, and psychological distress. Pearson correlation analyses examined the bivariate associations among study variables. Multiple linear regression analyses examined the moderating effects of MBI. Results revealed that both muscularity dissatisfaction and MBI were significantly and positively related to all outcome variables, except for a non-significant correlation between muscularity dissatisfaction and psychological distress in women. MBI was a significant moderator in men, not women, with muscularity dissatisfaction being more strongly and positively related to all outcome variables in men reporting higher MBI. Our study provides preliminary evidence supporting gender differences in the role of MBI in the associations of muscularity dissatisfaction with muscularity-oriented eating disorder psychopathology and psychosocial well-being.