Veterans who are 50-65 yrs, non-smoking, sedentary and weight stable with a BMI between 25-35 kg/m2 (120-150% desirable body weight) are recruited and screened via telephone, medical history, and physical exam. Exclusion criteria are: diabetes, hypertriglyceridemia (>400 mg/dl), history of cancer or myocardial infarction, clinical depression, renal, liver or hematologic disease, and medications that affect glucose or lipid metabolism (thiazides, estrogen replacement, beta-blockers). Changes in total and visceral body fat are measured by dual x-ray absorptiometry and computerized tomography, resting energy expenditure and fat oxidation rate by indirect calorimetry, and lipoprotein lipids by enzymatic assay. Glucose tolerance is assessed during a three-hour oral glucose tolerance test with measurement of glucose- and insulin levels every 30 minutes. LPL activity is measured in 3050mg pieces of subcutaneous abdominal and gluteal adipose tissue.