The use of sugar and starch-like foods for energy (carbohydrate metabolism) changes when people sleep. However, it is still not known if differences in the amount of nighttime sleep have an effect on the carbohydrate metabolism of people who have a relative with type 2 diabetes (parent, sibling, or grandparent). This study is being done to test the hypothesis that individual differences in habitual sleep duration may be related to differences in the carbohydrate metabolism of people who have a history of type 2 diabetes in their family.