The brain plays an integral role in how and what people eat. However, the brain's contribution to overeating is not well understood during sensitive developmental periods such as adolescence, when excessive weight gain and obesity prevalence are a significant concern.The proposed study will use functional magnetic resonance imaging to examine how the brain's response to excess energy is related to overeating in adolescents with and without obesity.

Inclusion Criteria:

• male or female
• 13-18 years-old
• resident of Colorado

Exclusion Criteria:

• weigh less than 88 pounds or have a BMI% rank of <10% for age and sex;
• have a physician's diagnosis of metabolic syndrome or diabetes (Type 1 or 2);
• have a physician's diagnosis of anorexia nervosa or bulimia nervosa;
• currently taking anti-psychotic medications (not including anti-depressant or anti- anxiety medications);
• have a non-MRI safe device (e.g. pacemaker or defibrillator) or metal in the body (e.g. metal pins, shrapnel);
• experience symptoms of claustrophobia when in small or closed-off places;
• are pregnant or plan to become pregnant

Adolescents with severe obesity enrolled from a specialty care lifesstyle medicine clinic and from the surrounding community. Adolescents with healthy weight enrolled from primary care clinic and from teh surrounding community.