Adolescent overweight and obesity have increased dramatically in the past several decades. High schools are well-positioned to deliver weight loss treatment to overweight and obese adolescents, as they have the facilities and staff to deliver a physical activity program, school nurses with the skills to provide counseling, and are easily accessible by adolescents. This exploratory study will test the feasibility and ability of a school-based intervention, consisting of school nurse counseling and a school-based exercise program, to reduce BMI and improve dietary quality, physical activity, and sedentary behaviors in overweight and obese adolescents. If effective, this could prove to be a cost-effective and relatively easy intervention to disseminate widely for significant public health impact.

Inclusion Criteria:

• enrolled in grades 9 - 12
• BMI > 85th percentile for age/sex
• able to understand and participate in the study
• able and willing to provide informed assent (adolescent) and consent (parent)
• English-speaking with at least one English-speaking parent

Exclusion Criteria:

• planning to move out of the area within the next 8 months
• medical condition that precludes adherence to study dietary recommendations (e.g., pregnancy, Crohn's disease, ulcerative colitis)
• diagnosis of a serious psychiatric illness (e.g., psychiatric hospitalization, eating disorder, suicidal) within the past 5 years
• genetic or endocrine causes of obesity (e.g., pradi Willi, Cushing's Syndrome)
• developmental delay that would prevent participation in the intervention or measurements
• prescribed medications associated with weight gain (e.g.,oral steroids)
• morbidly obese, defined as weighing > 300 pounds