Effectiveness of tailored multichannel interventions on weight loss among adolescents: a randomized controlled trial

Background Several weight loss interventions have been provided for adolescents. However, these interventions were often not adequately tailored to their perception. This study aims to investigate the effectiveness of tailored multichannel interventions on weight loss among adolescents. Methods This study is a randomized controlled trial. A total of 279 adolescents, whose Body Mass Index (BMI) was≥25 kg/m 2 , were recruited in January 2025 from eight non-medical colleges at Mansoura University, Mansoura, Egypt. For the intervention group (IG; n = 133), an intervention was developed based on the Health Belief Model (HBM). The intervention has been designed and administered by a multidisciplinary team for 5 months, until June 2025, via in-person meetings, telephone calls, and digital messages. The control group (CG; n = 146) received basic education over two face-to-face sessions. The primary outcome is the mean difference in BMI. Secondary outcomes include self-administered HBM constructs. All outcomes were assessed at baseline (T0), 2 months (T1), and 5 months (T2). Results The independent t -test revealed statistically significant differences between the groups in the scores of the BMI at T2 (−1.75, 95% CI: −2.48 to −1.02, p < 0.001, Cohen’s d = −0.57). Additionally, two-way repeated measures ANOVA demonstrated a statistically significant interaction effect (Group × Time), F (1.24, 342.36) = 49.72, p = <0.001, partial η 2 = 0.15, as well as statistically significant differences within-group, F (1.24, 342.36) = 29.73, p = <0.001, partial η 2 = 0.10. Regarding HBM, the intervention produced statistically significant main effects between and within groups over time for perceived susceptibility, benefits, self-efficacy, and internal cues to action (all p < 0.05). Conclusion Adolescents in the IG experienced significant weight loss and a positive change in their perception of weight management. The study findings suggest that such tailored multichannel interventions be integrated with other community-based participatory approaches to enhance external cues to action and overcome the perceived barriers in the long term. Clinical trial registration https://clinicaltrials.gov/study/NCT06767072 , NCT06767072.