Daytime vs. Delayed Eating Among Obese Individuals

Inclusion Criteria: * age 21-50 * BMI of 30-50 kg/m2 * stable weight (±10 lb) over the previous 6 months * women must be pre-menopausal with regular menstrual cycles Exclusion Criteria: * unstable, serious medical conditions * use of medicine linked to weight gain/loss * cardiac conditions * cancer * diabetes * autoimmune disease * use of illicit drugs, melatonin, diuretics or hypnotics * involved in a current weight loss program * presence of an untreated sleep disorder (determined by surveys and actigraphy) * those who work shift work * those with extreme chronotypes * habitual waking outside of 0600h-0930h * habitual bedtime \<2200h or \>2400h * sleep duration of \<6.5 or \>8.5 h/night. * psychiatric exclusions will be: depression (Patient Health Questionnaire-9 score ≥9), lifetime bipolar disorder, psychosis, or eating disorder; or any other severe psychiatric disorder judged to interfere with study adherence as assessed by the MINI International Neuropsychiatric Interview. * structured exercise \>3 d/wk, for \>30 min measured by exercise logs and actigraphy; normal activity levels are required during the study (±30 min/wk of baseline level).