Inclusion Criteria:

- Female

- Age > 20 and < 40

- Weight stable (change of less than 3 kg in the last 8 weeks), and within 10% of peak
body weight (not including pregnancy).

- BMI < 40 kg/m2 or > 30 kg/m2

Supplemental inclusion criteria for PCOS women:

- NIH criteria - confirmed by subjects' medical records.

Exclusion Criteria:

- Male

- Women who are pregnant or lactating (breast feeding)

- Post-menopausal women

- Women with hysterectomy

- Diagnosed with diabetes, or have a fasting blood sugar > 126 mg/dL.

- Untreated or symptomatic thyroid disease.

- Impaired kidney or liver function, as evidenced by your blood work

- Hypertension/ high blood pressure or are taking blood pressure medications

- Use of oral contraceptives or hormone replacement therapy.

- History of drug or alcohol abuse (> 3 drinks per day) in the last 5 years, or
psychiatric disease prohibiting adherence to study protocol.

- History of cancer within the last 5 years.

- History of organ transplant.

- History of HIV, active Hepatitis B or C, or Tuberculosis.

- History of heart attack/ myocardial infarction.

- Presence of clinically significant abnormalities on EKG.

- Current smokers (smoking within the past 3 months)

- Use of any medications known to influence glucose, fat and/or energy metabolism
within the last 3 months (e.g., growth hormone therapy, glucocorticoids [steroids],
etc.). Metformin for women with PCOS is allowed.