Obesity and its metabolic complications are leading causes of global morbidity and mortality. Evidence is mounting that inappropriate timing of food intake contributes to obesity. Specifically, late eating is associated with greater weight gain and metabolic syndrome. However, the mechanism by which late eating harms metabolism is not fully understood but may be related to mis-timing of food intake in relation to the body's endogenous circadian rhythm. Conversely, harmonization of eating timing with endogenous circadian rhythm may optimize metabolic health. In this study the investigators will use gold-standard methods of characterizing circadian rhythm in humans to examine the metabolic impacts food timing relative to endogenous circadian rhythm.