Introduction: Childhood obesity is a growing global health problem affecting millions of children. It leads to physical health issues like high blood pressure and liver disease, as well as emotional problems such as low self-esteem and depression. Early lifestyle changes in schools and homes can reduce these risks. Materials and Methods: This study included 100 children aged 7–15 years, divided equally into four groups: school-based intervention, combined school and home intervention, home-based intervention, and a control group. Data on body measurements, diet, physical activity, mental health, and obesity-related diseases were collected at the start, after 1 year, and after 5 years. Statistical tests compared changes across the groups. Results: Age and gender were fairly balanced across groups. At baseline, body weight and waist size were similar in all groups. After one year, BMI decreased significantly in intervention groups, especially in the combined group. These improvements lasted up to five years, where the combined program showed the best BMI control. Intervention groups also had less depression, better self-esteem, fewer obesity-related illnesses, more exercise, less screen time, healthier eating, and lower blood pressure than controls. Conclusion: Lifestyle programs, especially those combining school and home efforts, can effectively reduce childhood obesity, improve mental health, and lower risks for future diseases. Early and ongoing support from both schools and families is important for healthy child development.