Physical and Behavioral Traits of Overweight and Obese Adults

* INCLUSION CRITERIA: Obese subjects: 1. Obese men and women over the age of 18 years 2. BMI \> 30 Overweight subjects: 1. Overweight men and women over the age of 18 years 2. BMI \> 25 and \< 30 Control subjects (may be matched for age, sex and years of education): 1. Normal weight men and women over the age of 18 years 2. BMI \> 18.5 and \< 25 EXCLUSION CRITERIA: 1. Patients with significant physical limitations that may preclude them from completing the majority of the tests in this study 2. Current unstable medical conditions including cardiac ischemia, severe respiratory insufficiency requiring oxygen therapy, hepatic or cardiac failure as assessed by history and physical exam 3. Any psychiatric condition that would preclude participation in the study 4. Patients unwilling or unable to give informed consent 5. Pregnant woman. Additional exclusion for lean control subjects: 1. Previous history of obesity as an adolescent or adult 2. Current or past history of eating disorders such as anorexia nervosa or bulimia The NIH Patient Recruitment and Public Liaison Office will receive inquiries from interested study subjects. Pre-screening by this office will exclude patients who require more than minimal assistance to complete activities of daily living in order to select subjects who can safely participate in the full phenotyping protocol. All others will be contacted by the protocol team to review exclusion criteria. Eligible patients will be invited to Clinical Research Center for a screening visit.