The Impact of Time Restricted Eating on Type 2 Diabetes (EaT2DM)

January 15, 2026 updated by: Jose O. Aleman, MD PhD, Rockefeller University

The Impact of Time Restricted Eating on Type 2 Diabetes Study

Time-restricted feeding limits caloric intake to active daytime hours with fasting for 14 to 16 hours. It has shown great promise as a novel intervention for stabilizing blood glucose, reducing weight, and improving cardiovascular disease outcomes. However, this approach has not been tested on people with diabetes, a group that would benefit from improved blood glucose and weight loss.

The impact of Time-Restricted Eating on Type 2 Diabetes Study (EaT2D Study) is a randomized six-day weight stable crossover feeding study in the Day Patient/Outpatient unit of The Rockefeller Hospital investigating how the time of day that meals are eaten affects weight, blood sugar and blood pressure. The investigators will compare an early time-restricted eating intervention (80% of calories consumed before 2 pm) to a usual feeding pattern (50% of calories consumed after 4 pm) among 10 persons with type 2 diabetes to determine effects on blood sugar and small molecules found in the blood.

Studies have shown benefits of eating during active periods (mornings and early afternoon) for metabolic health (blood sugar, body weight) compared to eating during inactive periods (evening and bedtime). Eating earlier in the day may lead to reduced sugar stores, burning fat for energy, and decreased inflammation when compared to eating later in the day. The investigators will compare the effects of eating earlier during the day for six days versus later in the day for six days, on blood sugar, blood pressure, blood ketones, and other measures of metabolic health in diabetic participants. Studies in animals supports these benefits.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Detailed Description

Early Time Restricted Eating (eTRE) is a meal timing strategy that restricts the daily eating window to the first 6-8 waking hours of the day, while extending the fasting window between the final meal of the day and the first meal the following morning.

There is an increasing body of evidence that circadian misalignment caused by changes in sleeping and eating behaviors is a significant contributor to obesity and cardiometabolic disease, and late-night eating behaviors are associated with obesity, weight loss inhibition, and various cardiovascular disease risk factors. While the mechanisms underlying these correlations are not well understood, these effects are most likely due to suboptimal timing of caloric intake against diurnal variations in hormone and metabolite activity. Therefore, eTRE shows great promise as a novel intervention for addressing obesity and related cardiovascular outcomes. In support of this, recent studies have demonstrated weight-independent benefits of eTRE on measures of insulin sensitivity and cardiac risk. However, studies to date have primarily focused on metabolically healthy or prediabetic populations and the effect of this dietary practice on individuals with type 2 diabetes has not yet been evaluated.

To this end, the investigators propose to conduct a randomized isocaloric 15-day crossover feeding trial in the outpatient unit at The Rockefeller University Hospital (RUH) comparing an eTRE intervention (feeding window 8 AM-4 PM; 80% of calories consumed prior to 2 PM; remaining 20% to be consumed by 4 PM) to a Usual Feeding Pattern (UFP) (50% of calories consumed after 4 PM) among 10 persons with type 2 diabetes and obesity to determine effects on glycemic variation and various time-in-range metrics. The primary hypothesis of this study is that restriction of caloric intake to earlier in the day will have metabolic benefits in terms of glycemic variation and time in hyperglycemia relative to consuming the majority of calories later in the day, as in the control arm. Additionally, the investigators anticipate no increase in hypoglycemia in the eTRE arm compared to the UPF control arm. This feeding study provides a unique opportunity to study the weight-independent effects of eTRE on a population that has frequently been excluded from dietary studies in this area, yet for whom diet and lifestyle modifications are foundational components of treatment. Additionally, the proposed work will complement our recent study performed at Rockefeller University Hospital (RUH), "The Time-Restricted-Feeding Effects on Inflammation and Obesity" (TRIO) Study, which utilized a similar study design to show the weight-independent glycemic benefits of eTRE in individuals with prediabetes and obesity.

The investigators propose to obtain glucometric data including glycemic variation and various time in range metrics by Continuous Glucose Monitoring (CGM), circulating advanced glycation end-products (AGEs), and targeted plasma metabolomic profiles as surrogate measures of overall dysglycemia affected by the eTRE intervention in the RUH metabolic study.

The collaborative research proposed between RUH and New York University (NYU) Obesity Center in this application will take advantage of the expertise of both centers and advance the science of obesity and cardiovascular disease. Members of our team have extensive experience in clinical dietary studies and advanced glucometric analysis. The investigators will be able to evaluate the effectiveness of eTRE as a weight-independent therapeutic strategy for type 2 diabetes management and identify the metabolic pathways invoked, thereby synergistically expanding the work of each institution.

The rationale for this study is that early time-restricted eating (eTRE) has been shown to improve glycemic variation in a weight-neutral setting within 48 hours in individuals with prediabetes, making it a promising dietary intervention to mitigate dysglycemia. However, it has not been studied in individuals with type 2 diabetes.

Study Type

Interventional

Enrollment (Actual)

2

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10065
        • The Rockefeller University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Age 18-75 able to give consent
  2. BMI >25 kg/m2
  3. Hemoglobin A1C ≥ 6.5%
  4. Willing to eat only the food provided
  5. Willing to follow the feeding schedule, including fasting for 16 hours/day for six days.
  6. Usual sleep time is between 10 PM and 8 AM
  7. Fluent in the English language

Exclusion Criteria:

  1. Current use of anti-obesity medications (Ozempic, Mounjaro, Trulicity, Wegovy, Zepbound, Qsymia, Contrave, Saxenda, Victoza, Orlistat)
  2. Report history of Cirrhosis
  3. HIV positive
  4. Self-reported autoimmune disease (rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, psoriasis, etc.)
  5. Current use of steroids (inhalers are permissible)
  6. Currently pregnant
  7. Smoked tobacco within the last 3 months
  8. Allergy to adhesive tape
  9. Skips breakfast
  10. Followed TRF or intermittent fasting in the last 2 weeks
  11. Shift or night worker
  12. Current use of insulin
  13. Current use of sulfonylureas
  14. Current use of glucagon-like peptide-1 (GLP-1) receptor agonists
  15. Hemoglobin A1c >8%
  16. Unable to sync smartphone with Bluetooth for scale data
  17. Any medical, psychological, or social condition that, in the opinion of the investigator, would jeopardize the health or well-being of the participant during any study procedures or the integrity of the data.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Time restricted eating
Selection of the order of the arms is randomized prior to active study participation. Caloric requirements and meal selection are done during screening and calculated to maintain weight neutrality. In Arm 1, participants are required to start breakfast at 8 AM, complete lunch by 2 PM (80% of total daily calories) and snack by 4 PM (20% of calories). They then fast from 4 PM till 8 AM the next day (16 hour fast). This is done for six days. The next day is for testing (2 hour oral glucose tolerance test, resting energy expenditure, research and clinical blood tests) prior to crossover to Arm 2.
Other: Meal timing
Participants either eat all of their daily calories between 8 AM and 4 PM with 16 hours fasting for six days, or they eat the same meals ad lib daily for six days. After post-testing, they crossover to the other arm.
Other: Time restricted eating
Eating restricted to 8 AM - 2 PM for 80% of caloric intake, the remaining 20% consumed by 4 PM, subsequent 16-hour fasting (4 PM-8 AM) each day for six days while on Time Restricted Arm.
Placebo Comparator: Usual feeding pattern, with meals eaten ad lib
Participants consume the same meals as in the other arm, but may eat ad lib without prolonged fasting. This is done for six days. Post-testing including 2 hour oral glucose tolerance test, resting energy expenditure, and research and clinical blood tests are done the following day.
Other: Usual feeding pattern.
Participant consumes usual diet ad lib without enforced fasting period for six days while on Usual Feeding Pattern arm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in glycemic variation by Mean Amplitude of Glycemic Excursion (MAGE) in the Early Time Restricted Eating (eTRE) arm relative to the usual feeding pattern (UFP) arm between Day 1, Day 8, and Day 15. arm
Time Frame: From Day 1-15 of study intervention.
Glycemic variation (changes in glucose levels in milligrams per deciliter (mg/dL) will be measured by continuous glucose monitoring (Abbott Freestyle Libre) recorded every 5 minutes for the entire study, as well as 2-hour oral glucose tolerance testing (measured by glucose measurements in mg/dL every 30 minutes for 120 minutes), at baseline testing and upon completion of each arm (Days 1, 8, 15).
From Day 1-15 of study intervention.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diurnal and prandial variation of GLP-1 will correlate with improved glycemia (serum glucose measured in mg/dL) in the eTRE arm
Time Frame: Day 1 through Day 15
Measure of change in diurnal and prandial variation of GLP-1 levels during glucose tolerance test in the eTRE arm relative to the UPF arm between Days1, 8, and 15.
Day 1 through Day 15
Diurnal and fasting variation of beta-hydroxybutyrate will correlate with improved glycemia (glucose levels measured in mg/dL) in the eTRE arm
Time Frame: Day 1 through Day 15
Measure of change fasting beta-hydroxybutyrate levels in the eTRE arm relative to the UPF arm between Days 1, 8, and 15.
Day 1 through Day 15

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Rockefeller University

Collaborators

NYU Langone Health

Investigators

  • Principal Investigator: Jose Aleman, MD, PhD, The Rockefeller University Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 29, 2025

Primary Completion (Actual)

August 4, 2025

Study Completion (Actual)

August 4, 2025

Study Registration Dates

First Submitted

March 12, 2025

First Submitted That Met QC Criteria

March 19, 2025

First Posted (Actual)

March 20, 2025

Study Record Updates

Last Update Posted (Actual)

January 20, 2026

Last Update Submitted That Met QC Criteria

January 15, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • JAL-1056

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Individual participant data that underlie the results reported in the published article after deidentification (text, tables, figures and appendices)

IPD Sharing Time Frame

Beginning one year after publication, no end date

IPD Sharing Access Criteria

Researchers who provide a methodologically sound proposal. Proposals should be sent to jaleman@rockefeller.edu. To gain access, data requesters will need to sign a data access agreement.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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