Inclusion Criteria:  Men and women between 20 and 60 years of age, BMI 27 to 40 kg/m^2, non-smoker or stable smoking habits for at least 6 months prior to screening and agreement not to change such habits during the study; subjects on non-obesity prescription medication may be included.  Exclusion Criteria:  Weight change of >3.0 kg in the month prior to screening, weight loss of >10 kg in the 6 months prior to screening, calorie restriction diet (<1500 kcal/day) for a period of 4 months or more in the 12 months prior to screening, use of any other investigational drug(s) within 8 weeks prior to screening, abnormal baseline laboratory parameters (serum creatinine > 1.6 mg/dl; ALT, AST, total bilirubin > 2.0 times the upper limit of normal; triglycerides > 500 mg/dl, total cholesterol > 350 mg/dl, TSH outside of normal range), consumption of more than 1 alcoholic beverage per day, pregnancy or intention to become pregnant.