Evaluation of Five Novel Intervention Components in Online Obesity Treatment: Outcomes of a Randomized Factorial Experiment.

Objective: This study aimed to optimize weight loss outcomes in an online behavioral obesity treatment program by evaluating the effects of five novel intervention components using a factorial experiment informed by the multiphase optimization strategy framework.

Methods: A randomized factorial experiment tested 12-month weight loss resulting from an established online obesity treatment program with randomization to zero to five novel intervention components (interactive video feedback, tailored intervention to promote physical activity, skills for dysregulated eating, virtual reality skills training, and social support with friendly competition).

Results: Adults (N = 384; 83% female, 12% male, 5% another sex/gender or did not disclose; 23% racial and/or ethnic minority) with (mean ± SD) age of 53.5 ± 11.7 years and BMI of 35.0 ± 6.1 kg/m² were randomized. No intervention component independently improved weight loss (p values > 0.199). Interaction terms (p values < 0.01) suggest the combination of interactive video feedback, skills for dysregulated eating, and social support with friendly competition improved weight loss. Mediation analysis indicated that social support and dysregulated eating interventions influenced weight loss outcomes through improvements in social support for physical activity and dietary quality.

Conclusions: This study identified a combination of intervention components that may improve weight loss outcomes compared to the established online treatment program.

Trial registration: ClinicalTrials.gov identifier NCT04520256.