The purpose of this study is to study the effects of sleep restriction on the production of two hormones, cortisol and testosterone. The investigators aim to show that changing these hormones leads to insulin resistance, which is an important cause of type 2 diabetes mellitus. The investigators may also study the effect of sleep restriction on your food intake and cravings, mood, inflammation, metabolism (including bone), and other hormones. Inflammation is your body's response to stress and injury. Bone metabolism is a process of how your body regenerates (renews) new bone cells and removes old bone cells. Hormones are natural substances (materials) that are produced in the body and that influences (effects) the way the body grows or develops.