Many studies have reported that alcoholic beverage consumption, especially in the form of wine, reduces the risk of developing type 2 diabetes by as much as 40%. This association suggests that wine consumption may somehow improve the body's ability to control its blood glucose concentration. Indeed, it has been reported that when wine is consumed immediately prior to ingestion of glucose, the release of insulin is enhanced and blood glucose concentration is lowered. The mechanism of wine's effects on blood glucose concentration is unknown, but is likely related to its ethanol or antioxidant content. In this study, the investigators plan to test whether wine or plain ethanol (vodka) ingestion alters the control of blood glucose in subjects who have diabetes or pre-diabetes.

Our central hypothesis is that improvement in glycemic control by acute consumption of wine is mediated by ethanol. Subjects will have type 2 diabetes, pre-diabetes, and be sedentary and obese (BMI >30). Subjects' glycemic control will be assessed by an oral glucose tolerance test (OGTT) at three different time points. One OGTT will occur shortly after consumption of red wine, the second after consumption of vodka containing the identical amount of ethanol as the wine treatment, and the third OGTT will occur shortly after consumption of an equal volume of water. The three OGTTs will be administered in random order.

Inclusion Criteria:

• insulin resistant: diagnosed with pre-diabetes or fasting blood glucose >/= 97 mg/dL
• T2D: diagnosed by primary care physician
• at risk of type 2 diabetes (obesity and physically inactive)
• age: 21-65

Exclusion Criteria:

• smoking
• insulin use (other than once daily)
• physically active (>30 mins aerobic exercise two days/week)
• recent (>3 mo) changes in medication use or dose
• uncontrolled type two diabetes (HbA1C >10%)
• advanced retinopathy or neuropathy
• pregnancy