Testing the Adipose Expandability Hypothesis In Vivo During Overfeeding

Inclusion criteria

• Men and pre-menopausal women
• 18-42 years of age
• BMI 23-35 kg/m2 (± 0.5 will be accepted)
• Are willing to drink deuterium-labeled water (2H2O) for 8 weeks
• Are willing to be randomized to either a CTL or 30% OF group
• For women, if not using pharmaceutical (hormonal) contraception (i.e. birth control pills, vaginal ring, injections, or implant), must agree to use either a double barrier method as a form of birth control to prevent pregnancy (i.e. male condom with spermicide, with or without cervical cap or diaphragm); use implants or intrauterine contraceptive devices; have a tubal ligation (surgically sterile); practice abstinence; or be in an established relationship with a vasectomized or same sex partner during the entire duration of the study
• Must be willing to adhere to all study procedures, including attendance at all study visits
• If enrolled, agree to maintain the same level of physical activity throughout the duration of the study
• Must be willing to have blood stored for future research

Exclusion criteria

• Unstable weight in the last 3 months (± ~5% weight change)
• Diagnosis of Type 1 or 2 diabetes or a fasting blood glucose > 110 mg/dL
• Average screening blood pressure > 140/90 mmHg
• Diagnosis of major organ disease (e.g. heart, kidney, lung, thyroid, liver disease) or abnormal liver enzymes that are, in the opinion of the MI, clinically significant and represent a problem for study inclusion.
• Self-reported positive test for human immunodeficiency virus, hepatitis B or hepatitis C
• Any current or previous eating disorders
• Chronic use of systemic glucocorticoids (steroids), systemic adrenergic-stimulating agents, beta-blockers, antipsychotic medications, thiazolidinediones and other medications that may cause clinically significant weight gain or loss)
• Chronic use of prescription weight loss medications or over the counter weight loss medications which, in the opinion of the MI, will impact the study
• Chronic use of anti-depressant medications for less than 3 months
• Chronic smokers or users of tobacco products who cannot abstain for the duration of the inpatient visits
• Previous bariatric or other surgeries for obesity
• Had cancer in the last 5 years (some skin cancers acceptable)
• Pregnancy, breastfeeding, or planned pregnancy for the upcoming 6 months
• Partial or full hysterectomy
• PCOS
• Diagnosed psychotic conditions.