Making large changes or small changes to prevent weight gain in young adulthood: which is preferred and by whom?

Knowledge of participant treatment preferences can inform decision-making regarding treatment dissemination and future participant adoption. To compare participant perceptions of two evidence-based approaches for weight gain prevention in young adults to identify the intervention with the greatest likelihood of adoption. As part of a randomized trial (Study of Novel Approaches to Weight Gain Prevention [SNAP]; n = 599) testing weight gain prevention interventions in young adults (18–35 years), individuals assigned to self-regulation interventions using either large changes or small changes reported on perceived personal effectiveness and difficulty of treatment over 3 years. Treatment satisfaction at 2-year follow-up was also reported. Pre-randomization, participants believed the large change intervention would be more personally effective than the small change intervention, although they also considered it more complex. Older age, lower body mass index (p = 0.056), and desire to maintain versus lose weight predicted greater perceived effectiveness of the small change relative to large change intervention. Over follow-up, the large change intervention was no longer perceived as more effective, but perceived effectiveness aligned with assigned treatment. The small change intervention was rated as less complex than the large change intervention at 4 months, but not at other follow-ups. At study conclusion, participants were largely satisfied with both treatments; however, in the small change intervention, individuals who were not successful at preventing weight gain were less satisfied than individuals who were successful. The large and small change interventions are both appropriate for dissemination with no clear advantages based on the participant perceptions.