Angiotensin-(1-7) and Energy Expenditure in Human Obesity

Inclusion Criteria: * Men and women of all races * Capable of giving informed consent * Age 18-60 years * Body mass index (BMI) between 30-40 kg/m2 * Satisfactory history and physical exam Exclusion Criteria: * Age ≤ 17 or ≥ 61 years * Pregnant, nursing, or postmenopausal women * Decisional impairment * Prisoners * Alcohol or drug abuse * Current smokers * Highly trained athletes * Claustrophobia * Subjects with \>5% weight change in the past 3 months * Evidence of type I or type II diabetes (fasting glucose \> 126 mg/dL or use of anti-diabetic medications) * History of serious cardiovascular disease other than hypertension (e.g. myocardial infarction within 6 months, symptomatic coronary artery disease, presence of angina pectoris, significant arrhythmia, congestive heart failure, deep vein thrombosis, pulmonary embolism, second or third degree heart block, mitral valve stenosis, aortic stenosis, hypertrophic cardiomyopathy) or cerebrovascular disease (e.g. cerebral hemorrhage, stroke, transient Ischemic attack). * History or presence of immunological or hematological disorders * Impaired hepatic function (aspartate aminotransferase or alanine aminotransferase levels \>2 times upper limit of normal range) * Impaired renal function (serum creatinine \>2.0 mg/dl) * Anemia * Treatment with anticoagulants (e.g. warfarin) * Treatment with chronic systemic glucocorticoid therapy (\>7 consecutive days in 1 month) * Treatment with medications influencing energy expenditure (e.g. psychostimulants) * Treatment with any investigational drug in the 1-month preceding the study * Inability to give, or withdraw, informed consent