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Completed

NCT Number: NCT03504683

MEAL TIMING Study: 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 eating; TRE) improves blood sugar control and cardiovascular health. Preliminary studies suggest that TRE 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 TRE 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 TRE depend on the time of day that people eat. Participants will be assigned to one of three groups: (1) 'Early TRE' (eat between ~8 am-3 pm), (2) 'Mid-day TRE' (eat between ~1 pm - 8 pm), or (3) Control Schedule (~8 am - 8 pm) for 8 weeks. All food will be provided and matched between groups.

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Key information

Conditions

PreDiabetes Diabetes Mellitus Endocrine System Diseases Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases Prediabetic State

Age range

30 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Alabama at Birmingham

Birmingham, Alabama, 35294, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged 30-70 years old
  • Prediabetic as determined by HbA1c between 5.7-6.4% or fasting glucose between 100-125 mg/dl with HbA1c >= 5.1%
  • Fasting insulin less than 100.0 mU/l and, if HbA1c <5.7%, must also have fasting insulin >= 8.0 mU/l
  • BMI between 30-60 kg/m^2
  • Wake up at a regular time between 5-8 am

Exclusion criteria

  • Been diagnosed with diabetes or on diabetes medication or any medication known to affect glucose or 24-hour rhythms in blood pressure
  • On weight loss medication
  • Change in the dosage of a chronic medication within the past 2 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 (other than non-melanoma skin 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
  • Major change in health or medical history in the past 3 months
  • Currently perform overnight shift work
  • Regularly eat within a <10.5-hour period each day
  • Lost or gained more than 4% of weight in the past 2 months
  • Traveled more than 2 time zones away in the 2 months prior to enrolling in this study
  • Will travel outside the Central time zone in the 2 weeks prior to testing
  • Will travel more than 1 time zone away during this study
  • Behavioral factors or other circumstances that may make it difficult for you to follow the study requirements

Treatment and study plan

Early TRE

Behavioral

Eat between 8 am - 3 pm (or 7 am - 2 pm, if an early riser)

Other names: eTRE

Mid-day TRE

Behavioral

Eat between 1 pm - 8 pm (or 12 pm - 7 pm, if an early riser)

Other names: mTRE

Control Schedule

Behavioral

Eat between 8 am - 8 pm (or 7 am - 7 pm, if an early riser)

Primary outcomes

  1. Mean 24-hour glucose levels

    Time frame: 8 weeks

    Mean 24-hour glucose levels (mg/dl)

  2. Mean 24-hour insulin levels

    Time frame: 8 weeks

    Mean 24-hour insulin levels (mU/l)

  3. Mean 24-hour C-peptide levels

    Time frame: 8 weeks

    Mean 24-hour C-peptide levels (pmol/l). This is also a proxy for total 24-hour insulin secretion.

  4. Insulin sensitivity

    Time frame: 8 weeks

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

  5. Beta-cell responsivity index (a measure of beta-cell function)

    Time frame: 8 weeks

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

  6. Glucose AUCs

    Time frame: 8 weeks

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

  7. Insulin AUC

    Time frame: 8 weeks

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

  8. C-peptide AUC

    Time frame: 8 weeks

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

  9. Peak glucose and mean amplitude of glycemic excursions (MAGE) glucose values

    Time frame: 8 weeks

    mg/dl

Secondary outcomes

  1. Mean 24-hour systolic and diastolic blood pressure

    Time frame: 8 weeks

    mmHg

  2. Daily maximum value, minimum value, and amplitude of systolic and diastolic blood pressure

    Time frame: 8 weeks

    mmHg

  3. Percentage of individuals with non-dipping blood pressure phenotypes

    Time frame: 8 weeks

  4. Heart Rate

    Time frame: 8 weeks

    beats per minute

  5. Lipids

    Time frame: 8 weeks

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

  6. High Sensitivity C-Reactive Protein (hs-CRP)

    Time frame: 8 weeks

    mg/l

  7. Cortisol

    Time frame: 8 weeks

    μg/dl

  8. 8-isoprostane

    Time frame: 8 weeks

    pg/ml

Other outcomes

  1. Adherence

    Time frame: 8 weeks

    Percent adherence to assigned meal timing group

  2. Body weight

    Time frame: 8 weeks

    Change in body weight (kg) as measured by scale weight

  3. Appetite across the day

    Time frame: 8 weeks

    Subjective appetite as measured by Visual Analog Scales across the waking day

  4. Appetite

    Time frame: 8 weeks

    Subjective appetite as measured by retrospective Visual Analog Scales (VAS)

  5. Appetite and Cravings

    Time frame: 8 weeks

    Subjective appetite and cravings as measured by Likert scales

  6. Eating Self-Efficacy

    Time frame: 8 weeks

    Eating self-efficacy as measured by the Weight Loss Efficacy Lifestyle Questionnaire (WEL-8)

  7. Sleepiness

    Time frame: 8 weeks

    Sleepiness as measured by the Karolinska Sleepiness Scale (KSS) across the waking day

  8. Current and Preferred Eating Times

    Time frame: 8 weeks

    Current and preferred eating times as measured by a custom designed chrononutrition questionnaire

  9. Mood

    Time frame: 8 weeks

    Mood as measured by the Visual Analog Mood Scales (VAMS)

  10. Positive Affect

    Time frame: 8 weeks

    Positive Affect as measured by the PROMIS Positive Affect Short Form (PASF)

  11. Stress

    Time frame: 8 weeks

    Stress as measured by the Perceived Stress Scale (PSS)

  12. Anxiety

    Time frame: 8 weeks

    Anxiety as measured by the General Anxiety Disorder-7 (GAD-7)

  13. Depression

    Time frame: 8 weeks

    Depression as measured by the Patient Health Questionnaire-9 (PHQ-9)

  14. Sleep Quality

    Time frame: 8 weeks

    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.)

  15. Sleep Timing, Duration, and Chronotype

    Time frame: 8 weeks

    Sleep timing and duration as measured by the Munich Chronotype Questionnaire (MCTQ)

  16. Chronotype

    Time frame: 8 weeks

    Chronotype as assessed by the reduced Morningness-Eveningness Questionnaire (rMEQ)

  17. GPAQ

    Time frame: 8 weeks

    Physical activity as assessed by the General Physical Activity Questionnaire (GPAQ)

  18. Exit Interview

    Time frame: 8 weeks

    Qualitative data on experiences with the eating schedules and barriers, facilitators, and satisfaction factors

  19. Sleep timing outcomes

    Time frame: 8 weeks

    Sleep duration, sleep timing, sleep latency, and wake after sleep onset as measured by actigraphy watch. (These all have units of time)

  20. Sleep efficiency and disruption

    Time frame: 8 weeks

    Sleep efficiency (%) and awakenings (no.), as measured by actigraphy watch. (These all have dimensionless units.)

  21. Other sleep outcomes

    Time frame: 8 weeks

    Sleep Fragmentation Index (awakenings per time), as measured by actigraphy watch

Sponsors and collaborators

Lead sponsor

University of Alabama at Birmingham

Other

Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Official study title

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

Important dates

Study start
2020
Primary completion
2025
Study completion
2025
First posted
Apr 20, 2018
Registry last updated
May 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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