Descriptives and baseline ecological momentary assessed predictors of weight change over the course of psychological treatments for binge eating disorder

Objective: The objectives were to examine individual variability in weight change across psychological treatments for binge-eating disorder (BED) and to examine baseline predictors (i.e., BED symptoms, affect, and appetite) of weight change using ecological momentary assessment (EMA). Method: Adults with BED (N = 110) enrolled in a randomized clinical trial in which they received one of two psychological treatments for BED. At baseline, participants completed a 7-day EMA protocol measuring BED symptoms, affect, and appetite. Height and weight were measured at baseline, mid-treatment, end-of-treatment, and follow-up, and body mass index (BMI) was calculated. Results: On average, participants evidenced a 2% increase in BMI at end-of-treatment and a 1% increase between end-of-treatment and 6-month follow-up assessments. Although results showed that BMI increased over time, the quadratic term reflected a deceleration in this effect. There were interactions between positive affect and the linear trajectory across time predicting BMI, indicating that individuals reporting higher positive affect at baseline evidenced a flatter trajectory of weight gain. There was a main effect of overeating as assessed by EMA and interactions between overeating and linear and quadratic trajectories across time predicting BMI. Individuals who reported greater overeating at baseline had higher BMI across time. However, the BMI of individuals with lower overeating increased linearly, and increases in BMI among those with average or high rates of overeating appeared to stabilize over time. Conclusion: Despite the variability in weight change, baseline positive affect and overeating may be ecological targets for improving weight outcomes in psychological treatments for BED.