Exploring Dietary Restraint as a Mediator of Behavioral and Cognitive‐Behavioral Treatments on Outcomes for Patients With Binge‐Eating Disorder With Obesity

ABSTRACT Objective To explore dietary‐restraint as a mediator of binge eating and weight‐loss outcomes within a randomized controlled trial comparing cognitive‐behavioral therapy (CBT) and behavioral weight loss (BWL) for binge‐eating disorder (BED) with obesity. Methods Ninety participants were randomly assigned to CBT or BWL and assessed by evaluators blinded to conditions at pretreatment, throughout‐, and post‐treatment (6 months). Three dietary‐restraint measures (Eating Disorder Examination‐Questionnaire [EDE‐Q]‐Restraint, Three‐Factor Flexible‐Restraint and Rigid‐Restraint) were administered at pretreatment and after 2 months of treatment. Regression models examined whether changes at 2‐months in the restraint scales mediated the effects of treatment (CBT versus BWL) on binge eating and weight‐loss outcomes at post‐treatment. Results CBT and BWL had similar binge‐eating outcomes and similar changes in EDE‐Q‐restraint and flexible‐restraint. BWL had greater 2‐month increases in rigid‐restraint and greater weight‐loss at posttreatment than CBT, with results suggesting 2‐month changes in rigid‐restraint mediated the greater difference (>7 pounds) in weight‐loss. The observed mediation effect of 2.92 suggests 39% of total treatment‐effect on weight‐loss was mediated through 2‐month increases in rigid‐restraint. Discussion This secondary analysis within a trial comparing CBT and BWL for BED suggests early‐change in rigid‐restraint has a mediating effect of BWL on weight‐loss. Findings indicate that BWL improves binge eating and challenge views that dietary‐restraint might exacerbate binge eating in BED with obesity. Findings require confirmation using hypothesis‐testing in future trials. Trial Registration: Clinicaltrials.gov: NCT00537758 (“Treatment for Obesity and Binge Eating Disorder”)