The Feeding Exercise Trial in Adolescents (FETA) aimed to evaluate whether a community-based, parents-involving, combined physical activity and nutritional education program was effective in improving adiposity profiles in overweight and obese adolescents. A total of 181 overweight and obese adolescents aged 13-15 years old were randomized in the three study groups ("Diet & Activity," "Activity," and Control). The Activity intervention included a 45-minute, 3-day per week supervised training program, while the Diet & Activity intervention included a supplementary 15 minutes of group-based sessions attended by the parents. The intervention lasted 3 months and the participants were followed for another 3 months after the intervention. The participants were assessed for anthropometric measures and activity and fulfilled the modified version of the questionnaire "Family Eating and Activity Habits Questionnaire" (FEAHQ). Both "Activity" only and "Diet & Activity" groups reduced significantly (p < 0.001) their mean body mass index (BMI) (-1.1, 95% CI -1.3, -0.8, and -1.4, 95% CI -1.7, -1.2, respectively), waist circumference, systolic and diastolic blood pressure, pulses per minute, and 50 m sprint run test at 3 months, while greater reductions in BMI were observed at 6 months (-2.3, 95% CI -2.6, -2.0, and -3.1, 95% CI -3.3, -2.8). Significant changes in the total FEAHQ score were achieved only in the "Diet & Activity" group both at 3 months and at 6 months. FETA resulted in significant effects on improving adiposity profiles in overweight and obese adolescents, as well as family activity and feeding habits, maintained at 3 months follow-up.