Behavioral Chronotype: Impact on Sleep and Metabolism

Inclusion Criteria: * Healthy overweight and obese (25 kg/m2 ≤BMI\< 40 kg/m2) men and women * aged 30-75 years * self-report sleeping at least 6.5-hrs/night but no more than 9-hrs/night, between 21:00 and 09:00 * signed informed consent Exclusion Criteria: * participation in a medically managed weight loss program within the past year * undergone bariatric surgery * dietary restrictions * Subjects will not have undergone surgery, donated a unit of blood, worked night shifts or crossed any time zones, or participated in another clinical study within a month prior to the study. * pregnancy in women * lactating women * Female subjects must not be actively going through menopause. * prisoners * inability to consent * members of the study team * Females with a hemoglobin \< 11.5g/dL, and males with a hemoglobin \< 13.5 g/dl will be excluded from the study. * presence of a sleep disorder such as moderate or severe sleep apnea (AHI≥15), a Circadian Rhythm Sleep Disorder (DSM-V criteria for advance sleep phase syndrome, delayed sleep phase syndrome, non 24-h sleep disorder, irregular sleep disorder and shift-work related sleep disorder), * a diagnosis of diabetes based on history or screening tests * other forms of endocrine dysfunction including PCOS; * a history of cognitive or other neurological disorders; * a history of major psychiatric disorder based on DSM-V criteria, * the presence of unstable or serious medical conditions, * any GI disease that requires dietary adjustment…