Effect of autonomous motivation support on obesity prevention in early adolescents: a study protocol of cluster-randomized controlled trial based on the integrated SDT-TPB framework

The prevalence of obesity among early adolescents continues to rise, yet most existing interventions demonstrate only short-term efficacy. Children in early adolescence have increasingly strong autonomy, and enhancing their autonomous motivation holds promise for the long-term maintenance of healthy behavior, and further research is urgently needed. Based on an integral framework of Self-Determination Theory and Theory of Planned Behavior (SDT-TPB), this project will conduct a cluster-randomized controlled trial. This trial will compare an autonomous motivation support group against a control group, with four follow-up assessments over 2 years. We will examine between-group differences in autonomous motivation, health behaviors, and adiposity outcomes to evaluate the intervention’s immediate and long-term maintenance effects. Unlike previous approaches that focused primarily on behaviors, this study specifically targets the motivational drivers of behavior change. Considering the developmental characteristic of early adolescents and theoretical framework of SDT and TPB, this school-based cluster-randomized controlled trial is expected to elucidate the complete pathway from motivation to behavioral change. We anticipate that the findings will help overcome a key bottleneck in pediatric obesity interventions and advance strategies for chronic disease prevention and control. ICH GCP NCT06547567. Registered on 7 August 2024