A randomized controlled trial testing a digital intervention to promote weight loss and weight loss maintenance

OBJECTIVE: This study aimed to determine the effectiveness and cost-effectiveness of the Choosing Health program, which tailors support to an individual's weight loss and weight loss maintenance determinants among adults with overweight and obesity.

METHOD: We conducted a randomized controlled trial with a nested interrupted time series within-person design. Participants ( N = 288) were randomized to the Choosing Health digital intervention ( n = 145) or a control group ( n = 143). Intervention participants completed 90 days of Ecological Momentary Assessments, which were used to identify behavioral determinants to tailor an intervention. Control participants received nontailored weight loss advice via generic emails and eBook. Body weight (the primary outcome), blood pressure, and % body fat (secondary outcomes) measured at 3, 6 and 12 months were restructured into change of baseline scores and analyzed using multilevel regression analysis, with the three time points nested within subjects.

RESULTS: Findings revealed no significant difference in mean weight loss between groups at 6 months, controlled for baseline (primary outcome; mean difference = 0.78 kg), F(1, 175) = 1.44, p = .232. Intervention participants had higher weight loss at 12 months than control participants (mean difference = 2.05 kg), F(1, 108) = 2.96, p = .088); however, the difference was not statistically significant.

CONCLUSIONS: The results showed promising trends for the intervention group in weight loss maintenance measured at 12 months. The dropout rate was higher than expected, as the intervention was delivered during the COVID-19 pandemic making face-to-face assessments difficult. (PsycInfo Database Record (c) 2026 APA, all rights reserved).