A Study of the Functional Magnetic Resonance Imaging Response to Leptin and Pramlintide

Inclusion Criteria: * Age 18 year to 45 years of age * MI 18 to 25 kg/m2 or ≥ 30 kg/m2 * At maximal lifetime weight * Weight stable for at least 3 months Exclusion Criteria: * Those with a major medical illness or who require prescription medication, including: cancer, coronary artery disease, hypertension, and diabetes. * Subjects taking psychiatric or centrally-acting (CNS) medications or who are diagnosed with a psychiatric or neurological illness, including: * depression * anorexia * bulimia * seizure disorder. * Exercise \> 30 minutes, 3 times a week * Alcohol consumption \> 2 drinks / day * Weight \> 350 lbs (159 kg) (weight limit for MR machine) * Illicit drug use * Pregnancy * Extreme dietary habits as determined by a GCRC nutritionist: very high or low dietary carbohydrate or fat intakes * Those with a contraindication to exposure to strong magnetic fields: presence of metal in the body such as body piercing, shrapnel, cardiac pacemakers or aneurysm clips * Those with claustrophobia * Anaphylaxis and known hypersensitivity to E. coli-derived proteins * Allergies or contraindications to metreleptin or pramlintide * Renal or hepatic impairment * Women who are lactating * Tobacco use