The Effect of Time-restricted Feeding on Physiological Function in Middle-aged and Older Adults

Inclusion Criteria: * Ability to provide informed consent * Baseline brachial flow-mediated dilation (FMD) \< 6%Δ (rationale: non-invasive screening to ensure exclusion of subjects with exceptionally high baseline endothelial function. * Ability to perform motor and cognitive tests (e.g., can rise from a chair, walk for 2 min, climb 10 stairs) * Women will be confirmed as postmenopausal (either natural or surgical) based on cessation of menses for \>1 year. Exclusion Criteria: * Ages \<55 years or ≥80 years * Occupation that requires night-shift work or abnormal hours that would disrupt eating schedule * Dietary habit of regularly skipping meals, already eating within a \~10 hour window, or any other form of restrictive eating. * Unable to adhere to an 8 hour eating window for the length of the study period * Participation in regular vigorous aerobic/endurance exercise (\>3 vigorous bouts/week) * Not weight stable in the prior 3 months (\>2 kg weight change). * Body mass index (BMI) \>40 kg/m\^2 (rationale: vascular function measurements can be inaccurate in severely obese subjects) * Current smoking * Diagnosis of a chronic clinical disease (e.g., coronary artery/peripheral artery/cerebrovascular diseases, diabetes, chronic kidney disease requiring dialysis, neurological disorders or diseases that may affect motor/cognitive functions \[multiple sclerosis, Parkinson's disease, polio, Alzheimer's disease, dementia or other brain diseases of aging\]), except hypertension and hyperlipidemia. * Having unstable angina, acute myocardial infarction, coronary angioplasty, or aorto- coronary bypass surgery as defined by the occurrence of an event, symptom, surgery, or change in medication and/or dosage within 3 months prior to enrollment. * Having thyroid disease that is not controlled by medications or \<3 month's use of a particular medication and/or dosage (rationale: uncontrolled thyroid diseases are associated with alterations in vascular function). * Having past or present alcohol dependence or abuse, as defined by the American Psychiatry Association, Diagnostic and Statistical Manual of Mental Disorders