OBJECTIVE: This study aims to develop and validate "Chance2Act," a new web-based intervention, designed specifically to facilitate behavioral change in adults with T2D with obesity who are not ready to act toward weight loss. Then, the effectiveness of the newly developed intervention will be determined from a nonrandomized controlled trial.

METHODS: A web-based intervention will be developed based on the Transtheoretical Model targeting adults with T2D with obesity who are not ready to change for weight loss. Phase 1 will involve the development and validation of the web-based health intervention module. In phase 2, a nonrandomized controlled trial will be conducted in 2 government health clinics selected by the investigator. This is an unblinded study with a parallel assignment (ie, intervention vs control [usual care] with an allocation ratio of 1:1). A total of 124 study participants will be recruited, of which 62 participants will receive the Chance2Act intervention in addition to the usual care. The primary outcome is the changes in an individual's readiness from a stage of not being ready to change (precontemplation, contemplation, or preparation stage) to being ready for weight loss (action stage). The secondary outcomes include changes in self-efficacy, decisional balance, family support for weight loss, BMI, waist circumference, and body fat composition.

RESULTS: The phase 1 study will reveal the intervention's validity through the Content Validity Index and Face Validity Index, considering it valid if both indices exceed 0.83. The effectiveness of the intervention will be determined in phase 2, where the differences within and between groups will be analyzed in terms of the improvement of stages of change and all secondary outcomes as defined in the methodology. Data analysis for phase 2 will commence in 2024, with the anticipated publication of results in March 2024.

CONCLUSIONS: If proven effective, the result of the study may give valuable insights into the effective behavioral modification strategies for a web-based intervention targeting adults with T2D with obesity but not yet ready to change for weight loss. This intervention may be replicated or adopted in different settings, focusing on behavioral modification support that patients need. This study offers a deeper understanding of the application of behavior change techniques for a more holistic approach to obesity care in T2D.

TRIAL REGISTRATION: ClinicalTrials.gov NCT05736536; https://clinicaltrials.gov/study/NCT05736536.