The Temporal Trajectories of Stress and Affect Around Eating Events in Daily Life

Objective: Stress and affect are considered central to unhealthy snacking and dietary lapses, yet little is known about their temporal dynamics around such unhealthy eating events in daily life. We aimed to characterize the temporal trajectories of perceived stress, affect, and vagally mediat-ed heart rate variability (vmHRV; measure of cardiac vagal activity) surrounding eating events in daily life. Methods: We conducted two intensive longitudinal studies with healthy university students (Study 1: N = 67, days = 4, eating events analyzed = 139) and adults with a history of obesity actively engaged in weight loss maintenance (Study 2: N = 76, days = 6, eating events analyzed = 637). We used mixed-effects models to capture trends in stress and affect in the hours before and after the eating events. We additionally examined interindividual and contextual moderators.Results: Perceived stress did not show significant trajectories surrounding eating events. Be-fore unhealthy eating events, positive affect increased (Study 1), with curvilinear patterns indi-cating a reversal close to the event (Study 2). vmHRV decreased prior to unhealthy snacking (Study 1). After dietary lapses, negative affect decreased, and positive affect declined after eating events (Study 2). vmHRV decreased after unhealthy snacking (Study 1) or showed curvilinear patterns (Study 2). Trajectories were moderated by emotional eating style, unhealthy snacking habits, and social support.Conclusions: These descriptive findings improve our understanding of stress- and affect-related trajectories surrounding eating events. The moderation results suggest that vulnerability to and recovery from unhealthy eating events is characterized by person-specific and context-dependent changes.