The Time-Restricted Intake of Meals Study

Inclusion Criteria: * Prediabetes defined by HbA1c 5.7-6.4%, or type 2 diabetes with HbA1c 6.5-6.9% * Class I-III obesity (BMI 30-50 kg/m2) * If on medications for hypertension, stable regimen for at least past 6 months * Willingness to adjust timing of feeding * Willingness and ability to eat study diet and nothing else during run-in and intervention * Willingness to complete measurement procedures Exclusion Criteria: * Moderate to severe obstructive sleep apnea * Shift work; * Other sleep/circadian disorders: e.g., circadian phase delay or phase advance; restless legs syndrome, insomnia, narcolepsy, habitual sleep \<6 hours/night * Routinely ate within compressed time window in the past year (e.g., routinely eats all food within an 10-hour or narrower window, follows an intermittent fasting protocol) * Renal dysfunction (estimated Glomerular Filtration Rate (GFR) \<30 using the simplified Chronic Kidney Disease (CKD) Epidemiology Collaboration (EPI) equation 34) * Use of glucose-lowering medications, weight loss medications, medications for sleep disorders (sedative/hypnotic drugs, stimulants), lithium, systemic corticosteroids, diuretics, blood thinners requiring regular monitoring (e.g. warfarin), anti-psychotic drugs and antiretroviral therapy * Body weight \>400 pounds (limitation of facility scales) * \>1 drink per day of alcohol * Active substance use disorder or significant psychiatric/psychologic disorder that would interfere with participation * Significant food allergies, preferences, intolerances, or dietary supplements that would interfere with diet adherence * Weight loss or gain of ≥5% during past 6 months * Pregnant, planning to become pregnant, or breastfeeding * Planning to start a weight loss program * Planning to leave the area prior to end of study * Current participation in another clinical trial * Cancer diagnosis requiring active treatment in past two years or planned treatment (with exception of localized non-melanoma skin cancer) * Active inflammatory bowel disease, malabsorption, or history of major gastrointestinal surgery involving bowel resection * Myocardial infarction or stroke in past 6 months * Prior bariatric surgery * Any serious illness that would interfere with participation * Other conditions or situations at the discretion of the PI