Does Meal Timing Affect Energy Expenditure

Inclusion Criteria: * Are 20-45 years of age * Have a weight between 150 and 220 lbs * Have a body mass index between 25 and 35 kg/m2 inclusive (a number calculated from your height and weight) * If you are a female, have a regular menstrual cycle that is between 25 and 35 days long * If you are female, had your period within the last 35 days * Regularly go to sleep between 9:30 pm and 12:00 am * Regularly eat dinner 9 or more hours after eating breakfast * Are willing to have about 2/3 cup of your blood stored for future research related to this study Exclusion Criteria: * Have diabetes or are on anti-diabetes medication * Suffer from significant cardiovascular, renal (kidney), cardiac (heart), liver, lung or nervous system disease * Have stomach or intestinal problems * Regularly use medications such as steroids, beta blockers, adrenergic-stimulating agents, and laxatives * Take any medications or supplements known to affect sleep, circadian rhythms, or metabolism (with the exception that certain forms of birth control are allowed) * Have abnormal lab work that is clinically significant in the opinion of the study physician * Are pregnant or lactating * Take the Depo Provera shot, or use an Interuterine Device (IUD) or hormone patch for birth control * If you are on hormonal birth control, have been on a stable dose for less than 3 months * Have smoked or used nicotine/tobacco products within the last 3 months * Regularly do competitive sport training * Perform overnight shift work an average of one or more times per week * Have an irregular sleep schedule * Have an irregular eating schedule * Regularly drink 3 or more drinks of alcohol per day * Are not able or are unwilling to eat only the food and drink served to you by Pennington Biomedical, while in the study * Are not able or are unwilling to refrain from strenuous exercise while participating in the study * Are not able to spend 2 separate full days (for about 25 hours each) at Pennington Biomedical * Are not able to maintain a consistent sleep schedule while participating in the study * Are not able to maintain a consistent eating schedule while participating in the study * Are not able to stop drinking coffee and other caffeine-containing drinks on the day of and day prior to testing