Effect of Time-Restricted Feeding on 24-hour Glycemic Control, Blood Pressure, and Cardiovascular Disease Risk Factors

Effect of Time-Restricted Feeding on 24-hour Glycemic Control, Blood Pressure, and Cardiovascular Disease Risk Factors

Effect of Time-Restricted Feeding on 24-hour Glycemic Control, Blood Pressure, and Cardiovascular Disease Risk Factors in Adults With Prediabetes

One in three American adults have prediabetes, and up to 70% of adults with prediabetes eventually develop type 2 diabetes. With the high cost of treating diabetes, cost-effective approaches are needed to reduce the incidence of diabetes. One new strategy may be to change when people eat. Studies in rodents suggest that a form of intermittent fasting that limits eating to a short time period each day and involves fasting for the rest of the day (time-restricted feeding; TRF) improves blood sugar control and cardiovascular health. Preliminary studies suggest that TRF also improves blood sugar, weight loss, and cardiovascular health in humans. This study will be the first full-scale, controlled feeding trial to determine whether TRF can improve 24-hour blood sugar control, 24-hour blood pressure, and cardiovascular disease risk factors even when food intake is matched to the control group. This clinical trial will also determine whether the benefits of TRF depend on the time of day that people eat. Participants will be assigned to one of three groups: (1) 'Early TRF' (eat between ~8 am-3 pm), (2) 'Mid-day TRF' (eat between ~1 pm - 8 pm), or (3) Control Schedule (~8 am - 8 pm) for 10 weeks. All food will be provided and matched between groups.

Randomization will be stratified by fasting insulin. Within the lowest insulin strata, randomization will be further stratified by biological sex.

Mean value of insulin sensitivity (dl/kg/min/μU/ml) across the three identical meal tolerance tests, as measured by the Oral Minimal Model

Mean value of beta-cell responsivity across the three identical meal tolerance tests, as measured by the Oral Minimal Model

Glucose area-under-the-curve (mg/dl x hr) during each of three identical meal tolerance tests within a 24-hour period

Insulin area-under-the-curve (mU/l x hr) during each of three identical meal tolerance tests within a 24-hour period

C-peptide area-under-the-curve (pmol/l x hr) during each of three identical meal tolerance tests within a 24-hour period

Total cholesterol (mg/dl), LDL cholesterol (mg/dl), HDL cholesterol (mg/dl), and triglycerides (mg/dl)

Chronotype (i.e., mid-point of sleep in clock time) as measured by the Munich Chronotype Questionnaire

Sleep quality as assessed by the Pittsburgh Sleep Quality Index (PQSI) (This study will use the Global PQSI score, which ranges from 0-21, where higher values correspond to worse sleep quality.)

Inclusion Criteria: Aged 30-65 years old Prediabetic as determined by HbA1c between 5.7-6.4% or fasting glucose between 100-125 mg/dl BMI between 27-43 kg/m^2 Wake up at a regular time between 5-8 am Exclusion Criteria: On diabetes medication or any medication known to affect glucose or blood pressure Change in the dosage of a chronic medication within the past 3 months Have a clinically significant laboratory abnormality (e.g., abnormal hemoglobin levels) Significant gastrointestinal disease, major gastrointestinal surgery, or gallstones Significant cardiovascular, renal, cardiac, liver, lung, adrenal, or nervous system disease that might compromise the participant's safety or data validity Evidence of cancer within the last 5 years Pregnant or breastfeeding Diagnosed psychiatric conditions Sleep disorder, circadian disorder, or regularly sleep less than 6 hours per night Currently, perform overnight shift work Regularly eat within a <9-hour period each day Lost or gained more than 3 kg of weight in the past 3 months