Abstract
BACKGROUND: Self-efficacy is a modifiable intervention target in behavioral weight loss interventions. However, its role in the context of digital interventions is less clear. PURPOSE: To determine change in self-efficacy in a digital weight loss intervention, and whether self-efficacy is associated with engagement in self-monitoring diet or weight loss. METHODS: This is a secondary analysis of the GoalTracker study among 100 adults with overweight or obesity enrolled in a 12-week standalone digital weight loss intervention emphasizing daily self-monitoring. At baseline, 1 month, and 3 months, we assessed self-efficacy for controlling eating (via the Weight Efficacy Lifestyle Questionnaire; WELQ) and self-efficacy for tracking diet. Dietary self-monitoring engagement data were collected from the MyFitnessPal app. Weight was collected in person on a calibrated scale. Analyses included participants with complete data (N range: 72-99). RESULTS: Positive change from baseline to 1 month in self-efficacy for controlling eating was associated with higher dietary self-monitoring engagement (r = 0.21, P = .008) but not with 3-month weight change (r = -0.20, P = .052). Meanwhile, positive change from baseline to 1 month in self-efficacy for tracking diet was associated in a beneficial direction with both outcomes (r = 0.57, P < .001; r = -0.35, P < .001, respectively). However, on average, self-efficacy for controlling eating did not change over time while self-efficacy for tracking diet decreased (P < .001). CONCLUSION: Improvements in self-efficacy-particularly for tracking diet-early on in a digital weight loss intervention served as a mechanism of greater engagement and weight loss, highlighting the need for strengthening intervention strategies that promote early self-efficacy within a digital context.