Inclusion Criteria:

1. Healthy, non-diabetic women with "≥20 pound weight gain since their twenties"
2. Age: 35-55
3. Peri-menopausal or postmenopausal status
4. Body Mass Index (BMI) 25-35 kg/m2

5. Either:

   1. a single blood pressure recording ≥135/85 or the use of blood pressure medication OR
   2. HDL≤50mg/dl or triglycerides ≥150 mg/dl or the use of lipid modifying medication

6. Area-under-the-curve (AUC-)insulin level>100mcgU/ml along with normal fasting (≤100 mg/dl) & postprandial ((≤200 mg/dl) glucose determinations following a 75-gram standard oral glucose tolerance test.

   -

Exclusion Criteria:

1. known diabetes, fasting blood sugar ≥100 mg/dl or HbA-1-C≥6.0%
2. known hepatic disease or ALT>40
3. known renal disease or creatinine ≥ 1.4
4. known severe pulmonary disease
5. chronic acidosis of any etiology
6. Congestive heart failure (NYS Category 1), treated or untreated
7. Cancer - active within 5 years
8. current alcoholism or other substance abuse
9. co-morbid psychiatric disorder, which in the opinion of the screening physician would require concomitant psychotherapy as part of obesity management
10. currently untreated thyroid abnormality (TSH≤0.2 or ≥4mIU/L)
11. pregnancy or contemplation of pregnancy
12. use of TZD or metformin within the past year
13. allergy to TZD or biguanide
14. use of FDA approved or alternate obesity agent within 6 months of the study
15. history of pseudotumor cerebri
16. other impairment, such as a history of medication noncompliance, which in the judgment of the screening clinician, would preclude active study participation.
17. history of known or suspected heart disease