Abstract
OBJECTIVE: Theories suggest that elevated negative affect and weight/shape concerns explain both who is affected by bulimic symptoms as well as when bulimic symptoms occur, suggesting that individual differences predict within-subject differences. However, few studies have tested this theoretical premise. METHOD: In the present study, participants (N = 119) diagnosed with bulimia nervosa (N = 57), purging disorder (N = 31), and non-eating disorder controls (N = 31) completed measures of negative affect and weight/shape concerns and later made momentary affect and weight/shape concerns ratings before and after an ad lib meal. RESULTS: State negative affect and weight/shape concerns increased post-meal. No moderating effect of trait negative affect was observed for state affect. In contrast, between-subject differences in weight/shape concerns moderated within-subject increases in state weight/shape concerns. Diagnostic group did not account for this effect. DISCUSSION: Findings point to viable treatment targets for disordered eating. Targeting elevated weight/shape concerns early in interventions could facilitate reductions in purging after food intake for bulimia nervosa and purging disorder. PUBLIC SIGNIFICANCE: In the present study, individual differences in weight/shape concerns at baseline predicted greater increases in state weight/shape concerns following eating. These effects were maintained when considering possible differences related to presence and type of eating disorder. Results suggest that targeting weight/shape concerns earlier in treatment may be important for reducing maladaptive responses to eating across eating disorders.