Background: Behavioral modification interventions based on Social Cognitive Theory are needed to improve healthy lifestyle compliance among adolescents.
Objective: This study aimed to develop and examine the effectiveness of a behavioral modification intervention model based on Social Cognitive Theory to improve healthy lifestyle compliance among adolescents
Methods: This study employed a mixed-method sequential exploratory design consisting of qualitative and quantitative approaches. The quantitative phase used a one-group pretest–posttest design involving 100 adolescents selected through purposive sampling. Data were collected using a healthy lifestyle compliance questionnaire that had been tested for validity and reliability. The intervention was conducted through four stages: introduction, preparation, action, and maintenance. Data were analyzed using paired t-test and Cohen’s d effect size analysis with a significance level of p < 0.05 using SPSS version 25.0.
Results: The mean healthy lifestyle compliance score increased significantly from 61.42 ± 8.53 before intervention to 78.67 ± 7.14 after intervention, with a mean difference of 17.25 points (p < 0.001; 95% CI: 15.09–19.41). The intervention demonstrated a large effect size with Cohen’s d value of 1.24. Multivariate analysis showed that self-efficacy (p < 0.001), self-regulation (p = 0.001), family support (p = 0.003), and peer support (p = 0.005) were significantly associated with healthy lifestyle compliance after intervention.
Conclusion: The behavioral modification intervention model based on Social Cognitive Theory was effective in improving healthy lifestyle compliance among adolescents.