Insulin is a hormone produced by the body that lets sugar into the cells, where it is used for energy. Insulin resistance occurs when the body's cells have a decreased ability to react to insulin. This leads to an increase in insulin secretion. Over time, insulin resistance can lead to higher levels of sugar in the blood (diabetes), and can also contribute to obesity, high blood pressure, high cholesterol levels and heart disease. There are no simple tests to actually diagnose insulin resistance. Currently, the glucose tolerance test is used to diagnose IR, but it involves several blood draws over a 2-hour period. Another purpose of this study is to compare a blood test involving only one blood draw to the 2-hour glucose tolerance test, which involves several blood draws over a 2-hour period.