This study will test whether adding peer support and online education can help college students manage their weight and improve their mood: we plan to enroll 300 full-time university students and randomly assign them to one of three six-month groups (monthly in-person health talks and weekly emailed tips alone; those activities plus biweekly peer-mentor meetings and an online chat group; or those activities plus a custom app delivering weekly lessons, monthly expert live Q&A, and self-tracking tools). We will measure weight, body mass index (BMI), and scores on standard questionnaires for depression (PHQ-9), anxiety (GAD-7) and life satisfaction (SWLS) at baseline, three months and six months to compare the effectiveness of each approach. By identifying which combination of face-to-face support and digital tools produces the greatest improvements, we aim to inform low-cost, scalable programs to help students maintain a healthy weight and emotional well-being.

Inclusion Criteria:

• Full-time undergraduate students aged 18-25 years
• Baseline BMI ≥ 24.0 kg/m²
• Able to provide informed consent
• Owns a smartphone or computer with internet access
• Willing to attend monthly lectures and complete online modules

Exclusion Criteria:

• Current participation in another weight-management or psychological intervention program
• Diagnosis of an eating disorder, severe psychiatric illness, or medical condition affecting weight (e.g., hyperthyroidism)
• Pregnant or planning pregnancy during the study period
• Any physical limitation precluding participation in light-to-moderate physical activity
• Inability to communicate in the language of intervention materials

The research team will conduct in-depth analyses of key scientific questions and will maintain an embargo period to secure publication priority and preserve the integrity of the study's findings; after this period, de-identified individual participant data will be made available to qualified researchers upon request.