In this study the Investigators are examining the effects of a 12-week exercise program (intervention) on measures of appetite and food intake regulation in overweight to mildly obese healthy adults. The Investigators hypothesize that individuals who lose a significant amount of weight in response to the intervention will show a reduction in the brain response to food cues as measured by functional magnetic resonance imaging (fMRI) when compared to those who do not lose weight. These changes in neuronal activity will be associated to physiologic and behavioral measures.

Inclusion Criteria:

• all ethnic groups and both genders;
• age: 21-45 yrs;
• BMI: 27-35;
• weight stable within +/- 5 percent in the last 6 months;
• sedentary (less than 1 hour of planned physical activity by self-report).

Exclusion Criteria:

• history of cardiovascular disease (CVD), diabetes mellitus, uncontrolled hypertension, untreated thyroid disease, renal disease, hepatic disease, or any other medical condition affecting weight or energy metabolism;
• unable to effectively exercise due to cardiac, pulmonary, neurologic or orthopedic reasons;
• unable to pass screening graded exercise treadmill test;
• currently smoking;
• medications affecting weight, Energy Intake (EI) or Energy Expenditure (EE) in the last 6 months;
• weight loss or weight gain of >5 percent in past 6 months;
• currently pregnant, lactating or less than 6 months post-partum;
• bariatric surgery;
• major psychiatric disorder, presence of alcohol or substance abuse, current depression by history and/or a score >21 on the he Center for Epidemiologic Studies Depression Scale (CES-D), history of eating disorders and/or a score of >20 on the EATS-26;
• contraindication to MRI