Scientists have demonstrated that electronic health (eHealth) and mobile health (mHealth) interventions can modestly but meaningfully improve physical activity, diet, and weight-related outcomes in children and adolescents. A comprehensive umbrella review published in the Journal of Medical Internet Research synthesized evidence from 25 systematic reviews, covering 440 randomized trials with over 130,000 young participants. The study aimed to evaluate the effectiveness of digital tools—including apps, websites, wearables, and text messaging—in promoting critical lifestyle behaviors among youth. These behaviors, such as moderate to vigorous physical activity (MVPA), fruit and vegetable intake, and reducing sedentary time, profoundly impact immediate and long-term health outcomes, including obesity and chronic disease risk. Researchers conducted a pre-registered review using PRISMA guidelines, systematically assessing meta-analyses of randomized controlled trials targeting children and adolescents under 18 years. Interventions included a range of digital platforms offering personalized coaching, goal setting, feedback, gamification, and social support. The effects on physical activity, diet, sleep, sedentary behavior, BMI, and body weight were pooled using random-effects models. Subgroup analyses investigated age, intervention duration, delivery mode, and study quality. Digital health interventions yielded small but consistent benefits in increasing MVPA (SMD 0.18) and total physical activity (SMD 0.24). Dietary improvements included reduced fat intake and increased fruit and vegetable consumption. Weight outcomes showed decreased BMI (SMD −0.19) and body weight (SMD −0.15), alongside reductions in body fat percentage. Wearable devices produced the most significant reductions in sedentary behavior, while app-based programs achieved the largest BMI improvements, likely through interactive self-monitoring and gamified goal-setting. Sleep outcomes remained largely unchanged, and sedentary behavior effects were mixed. Shorter interventions (<8 weeks) were more effective at increasing physical activity, whereas longer ones (>12 weeks) better aided weight loss. Despite some variability, these modest effect sizes suggest that digital interventions can complement traditional health promotion, especially when integrated into schools and pediatric care. Lead researchers advocate for expanded, high-quality trials focused on long-term engagement strategies, equitable access, and tailored digital health solutions to amplify benefits for youth. REFERENCE: Singh, B., Ahmed, M., Staiano, A., Vasiloglou, M., Gough, C., Petersen, J., Yin, Z., Vandelanotte, C., Kracht, C., Fiedler, J., Timm, I., Dallinga, J., Sivakumar, B., Baumann, H., Huong, C., Wunsch, K., Suárez-Reyes, M., Schoeppe, S., Button, A., Spring, K., & Maher, C. (2025). Lifestyle eHealth and mHealth Interventions for Children and Adolescents: Systematic Umbrella Review and Meta–Meta-Analysis. J Med Internet Res, 27. DOI: 10.2196/69065, https://www.jmir.org/2025/1/e69065