Post-Treatment Daily Dynamics of Negative Affect, Stress, and Eating Behavior in Youth with Obesity: The Role of Resting Heart Rate Variability

Abstract Background. Adolescents are at heightened risk for weight regain following inpatient obesity treatment, yet little is known about the momentary emotional processes that may undermine sustained treatment success. Therefore, current study examined within-person associations between negative affect, stress intensity, and maladaptive eating behaviors during the early post-treatment period, and investigated resting heart rate variability (HRV) as a predictor of maladaptive eating and of individual differences in affect–eating associations. Methods. Seventy adolescents aged 13–19 years (M = 15.7, SD = 1.76; 63% girls) who completed inpatient obesity treatment participated in an ecological momentary assessment (EMA) during the first two months after discharge. Participants reported negative affect, stress intensity, and eating behaviors five times per day for two 7-day periods. Resting HRV was assessed prior to EMA, at treatment completion. The main study hypotheses and analyses were preregistered (see https://osf.io/67pxb). Results. Dynamic structural equation modeling showed that higher stress intensity predicted increased emotional eating at the subsequent assessment. The association between negative affect and later emotional eating was less certain. Emotional and reactive eating both predicted higher subsequent negative affect. Neither negative affect nor stress intensity predicted reactive eating. Resting HRV did not predict average levels of maladaptive eating or individual differences in within-person associations. Conclusions. Emotional eating appears to be triggered by daily stressors and may contribute to subsequent increases in negative affect, whereas reactive eating primarily predicts later distress. These findings underscore the importance of targeting daily emotion and stress regulation processes and providing close support during the early post-discharge period.