Time Restricted Feeding and Metabolic Rhythms

Inclusion Criteria: * Men and women with overweight and class I obesity (N=12, Age=20-50 years; BMI 25-35 kg/m2) * Low physical activity level (≤150 min/wk of moderate-to-vigorous activity); * For Females- Not currently pregnant or lactating and not pregnant within the past 6 months * Habitually consume food over a window of \>12 h/day; * Pass a medical and physical screening performed by the study physician. * Report a habitual, regular sleep-wake cycle for the month preceding screening that involved going to bed between 2200 and 0100h and getting up between 0600 and 0900 h with \>7 h and \<9.25 h in bed; * Agree to eat control diets at imposed times for 1 week prior to the inpatient CTRC visits; * Agree to keep a regular sleep/wake schedule for the duration of the study * Possess a smart phone to install and utilize the meal timing application. Exclusion Criteria: * Subjects must not be currently participating in another research study that would influence their safe participation in this study. For example, subjects must not be participating in a research study in which they ingest experimental medication, or which involves blood samples, since both of these factors could increase risk of participation; * Being considered unsafe to participate as determined by the study physician; * Taking medications affecting weight, triglycerides, energy intake/energy expenditure, or sleep in the last 3 months; * Having abnormal blood chemistry and/or hematology as deemed significant by the study physician; o Have one or more of the following out-of-range values measured on a fasting blood sample: glucose \> 126 mg/dl, HbA1c \> 6.5%, thyroid stimulating hormone \<0.5 or \>5.0 uU/ml. Subjects who may be anemic (hemoglobin \<14.5 g/dl men, \<12.3 g/dl women), have abnormal liver function tests (alanine amino transferase \> 47 U/l, aspartate aminotransferase, \> 47 U/l, alkaline phosphatase \<39 or \>117 U/l) or creatinine (\>1.1 mg/dl) * Significant abnormality in clinical laboratory values * Ever having a history of systemic, psychiatric, neurological disease, or drug and alcohol abuse; * History of cardiovascular disease, diabetes, uncontrolled hypertension, untreated thyroid, renal, hepatic diseases, dyslipidemia or any other medical condition affecting weight or lipid metabolism; * Score \> 18 on Beck Depression Index (BDI) will require further assessment by the study physician to determine if it is appropriate for the subject to participate in the study; * Use of a continuous positive airway pressure (CPAP) device for the treatment of obstructive sleep apnea (OSA). A score of \>10 on the Epworth sleepiness scale or \>5 on the Pittsburgh Sleep Quality Index will require further assessment by the study physician to determine if it is appropriate for the subject to participate in the study; * Being positive for human immunodeficiency virus or hepatitis B or C; * Being a smoker or having been a smoker in the previous 6 months; * Abnormal eating patterns identified by registered dietician interview (dietary fat\<15%, dietary fat\>45%, dietary protein \>30%); * Working night shifts; * Night eating syndrome (at least 25% of food intake is consumed after the evening meal and/or at least two episodes of nocturnal eating per week); * Traveling \> 2 time zones 2 weeks prior to an inpatient CTRC study visit; * Currently participating in any formal weight loss or physical activity programs or clinical trials. * Having a clinically significant allergy (e.g., to food stuffs such as shellfish, peanuts); * Celiac disease or known sensitivity to gluten (the metabolic kitchen is not gluten free certified and cannot accommodate this dietary restriction)