Testing the relative associations of different components of dietary restraint on psychological functioning in anorexia nervosa and bulimia nervosa.

Although empirical evidence identifies dietary restraint as a transdiagnostic eating disorder maintaining mechanism, the distinctiveness and significance of the different behavioural and cognitive components of dietary restraint are poorly understood. The present study examined the relative associations of the purportedly distinct dietary restraint components (intention to restrict, delayed eating, food avoidance, and diet rules) with measures of psychological distress (depression, anxiety, and stress), disability, and core eating disorder symptoms (overvaluation and binge eating) in patients with anorexia nervosa (AN) and bulimia nervosa (BN). Data were analysed from a treatment-seeking sample of individuals with AN (n = 124) and BN (n = 54). Intention to restrict, food avoidance, and diet rules were strongly related to each other (all r's > 0.78), but only weakly-moderately related to delayed eating behaviours (all r's < 0.47). In subsequent moderated ridge regression analyses, delayed eating was the only restraint component to independently predict variance in measures of psychological distress. Patient diagnosis did not moderate these associations. Overall, findings indicate that delayed eating behaviours may be a distinct component from other indices of dietary restraint (e.g., intention to restrict, food avoidance, diet rules). This study highlights the potential importance of ensuring that delayed eating behaviours are screened, assessed, and targeted early in treatment for patients with AN and BN.