Inclusion Criteria:  Age 18-65 Bariatric Surgery patients: 12-18 months post-operation. Medical weight loss patients: patients of the bariatric weight loss clinic, weight loss of 7% body mass via intentional weight loss within past 6 months; BMI >25 kg/m2 prior to intentional weight loss; stable for 3 months on medications. Lifestyle weight loss: weight loss of 7% body mass via intentional weight loss within past 6 months; BMI >25 kg/m2 prior to intentional weight loss.  Exclusion Criteria:  Uncontrolled cardiovascular, metabolic, renal, or pulmonary disease; cancer treatment in past 5 years; untreated thyroid disease or other medical condition affecting weight or energy metabolism; severe food allergies; women who are pregnant, lactating, or planning pregnancy during participation in the trial; active psychiatric issues Additional criteria specific to patients with history of bariatric surgery: <12 months post-op; weight regain of >5% of body mass postoperation; history of admittance to rehabilitation facility; history of post-op complications that require recent inpatient management; patients who were required to stay in the hospital >1 week post-op; revision surgery patients; heart failure patients.