Intensive longitudinal assessment of stress and stress-related concepts across a weight loss program: Protocol for a longitudinal ecological momentary assessment study

Background Fluctuations in daily stress and the inability to cope with this stress (i.e., coping) can negatively impact behavior and potentially weight loss. Longitudinal studies using ecological momentary assessment (EMA) of psychological factors and behavior may inform interventions that can be adapted in real-time to modify stress and stress-related factors to enhance weight loss. This study’s purpose is to examine variability in stress and stress-related concepts and weight loss during a behavioral weight loss program with the intent of this informing future interventions. Methods Individuals with obesity (body mass index: ≥ 30 kg/m 2 ) who are newly enrolled in an existing community-based behavioral weight loss programs will be recruited. Participants will complete four visits, to coincide with before program (week-0), early program (6-weeks), program mid-point (3-months), and program end (6-months). Each visit will include height, weight, and questionnaires related to chronic stress and coping, and weight-related behaviors. Participants will then complete at least 14-days of EMA, including one morning survey, four signal-contingent surveys during fixed 3-hour windows, and one night-time survey daily via a smartphone application. During these 14-days, participants will also complete device-based measures for physical activity and sleep and waking saliva collection to evaluate cortisol. The primary exposure is the difference (i.e., variability) in signal-contingent survey stress, coping, and affect at baseline. The primary outcome is weight change across 6-months. This study received initial startup in March 2024, and was registered in Clinical Trials in October 2024. The study began recruitment in March 2025 and anticipate completion in early 2027. Discussion Findings may inform justification for the pursuit of an ecological momentary intervention focused on improving stress while engaging in a behavioral weight loss intervention to support behavior change and potentially weight loss. Trial registration ClinicalTrials.gov NCT06668259