The use of energy from food changes when people sleep. However, it is still not known if differences in the amount of nighttime sleep have an effect on the amount of energy that people who have a relative with type 2 diabetes (parent, sibling, or grandparent) use to perform their daily activities. This study is being done to test the hypothesis that the daily use of energy in people who have a history of type 2 diabetes in their family will be different after they have slept short hours for 16 days in comparison to when they have slept longer hours for 16 days.