Time Restricted Eating for Weight Management

July 24, 2026 updated by: Krista Varady, University of Illinois at Chicago
A 12-month randomized, controlled, parallel-arm trial, divided into 2 consecutive periods: (1) 6-month weight loss period; and (2) 6-month weight maintenance, will be implemented. Adults with obesity will be randomized to 1 of 3 groups: (1) 8h-TRE, ad libitum food intake from 12pm to 8 pm, fasting from 8 pm to 12 pm daily, (2) CR, 25% energy restriction every day; or 3) control, ad libitum food intake daily, eating within more than 10 hours per day.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Time restricted eating (TRE) has become a popular weight loss regimen. The sudden rise in popularity of TRE is mostly likely due to is its sheer simplicity, and the fact that it does not require individuals to count calories in order to lose weight. Participants are simply asked to consume all food within a specified time frame and fast with energy free beverages for the remaining hours of the day. Evidence shows that when people with obesity limit their eating window to 6 to 8 hours per day, they naturally reduce energy intake by 350-500 calories. From a clinical standpoint, these findings are paramount. One of the main reasons for subject attrition with traditional dieting, i.e. daily calorie restriction (CR), is frustration with having to count calories every day. TRE regimens are able to side-step this requirement by allowing participants to simply "watch the clock" instead of monitoring calories, while still producing significant weight loss and metabolic health improvements. This feature of TRE has the potential to improve long-term adherence to the diet, and in turn produce lasting weight control in adults with obesity.

Accordingly, we conducted a one-year, randomized, controlled trial to compare the effects of late TRE (eating all food between 12:00 pm to 8:00 pm, without calorie counting), versus CR (25% energy restriction daily), and a control group eating over a period of 10 or more hours, on body weight and metabolic risk factors in a diverse group of American adults with obesity. We hypothesized that the TRE group would achieve greater weight loss, and experience more pronounced improvements in insulin sensitivity during the 6-month weight loss phase, compared to CR and control participants. We also hypothesized that the TRE group would better maintain their weight loss and sustain their improvements in insulin sensitivity during the 6-month weight maintenance phase, when compared to the CR and control participants.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
90

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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
    • Illinois
      • Chicago, Illinois, United States, 60612
        • University of Illinois Chicago

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria:

  • Age between 18 to 65 years old
  • BMI between 30 and 50 kg/m2
  • Sedentary or lightly active (<60 minutes/week of light activity for the 3 months prior to the study)

Exclusion criteria:

  • • Type 1 DM or Type 2 DM
  • History of eating disorders (anorexia, bulimia, or binge eating disorder)
  • Are not weight stable for 3 months prior to the beginning of study (weight gain or loss > 4 kg)
  • Are not able to keep a food diary or activity log for 7 consecutive days during screening
  • Are taking drugs that influence study outcomes (weight loss, glucose-lowering medications)
  • Are perimenopausal or have an irregular menstrual cycle (menses that does not appear every 27-32 days)
  • Are eating within less than a 10-hour window at baseline
  • Are pregnant, or trying to become pregnant
  • Are night shift workers
  • Are smokers

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 8-hour Time restricted eating
Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)
Other: 8-hour Time restricted eating
Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)
Experimental: Calorie restriction
25% energy restriction every day
Other: Calorie restriction
25% energy restriction every day
No Intervention: Control
Usual diet, Ad libitum intake, eating within >10 hours per day

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Body Weight
Time Frame: Measured at month 0 and 12
Measured by an electronic scale
Measured at month 0 and 12

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in Fat Mass
Time Frame: Measured at month 0 and 12
Measured by DXA
Measured at month 0 and 12
Change in Insulin Resistance
Time Frame: Measured at month 0 12
Measured by Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Values above 2.5 generally considered an indicator of insulin resistance. Higher values indicate greater insulin resistance while lower values indicate lower insulin resistance. HOMA-IR = [glucose (mmol/L) × insulin (μU/L)]/22.5.
Measured at month 0 12
Change in Insulin Sensitivity
Time Frame: Measured at month 0 and 12
Measured by Quantitative Insulin Sensitivity Check Index (QUICKI). QUICKI calculated as = 1/[log (fasting insulin, U/ml) + log (fasting glucose, mg/dl)]. Higher scores (typically > 0.45) indicate high insulin sensitivity. Lower scores (generally ≤ 0.33 or 0.34) indicate decreased insulin sensitivity and an increased risk for insulin resistance or type 2 diabetes.
Measured at month 0 and 12
Change in Fasting Glucose
Time Frame: Measured at month 0 and 12
Measured by a commercial lab (Medstar, IL)
Measured at month 0 and 12
Change in HbA1c
Time Frame: Measured at month 0 and 12
Measured by a commercial lab (Medstar, IL)
Measured at month 0 and 12
Change in Fasting Insulin
Time Frame: Measured at month 0 and 12
Measured by a commercial lab (Medstar, IL)
Measured at month 0 and 12
Change in Systolic Blood Pressure
Time Frame: Measured at month 0 and 12
Measured by a blood pressure cuff
Measured at month 0 and 12
Change in Diastolic Blood Pressure
Time Frame: Measured at month 0 and 12
Measured by a blood pressure cuff
Measured at month 0 and 12
Change in LDL Cholesterol
Time Frame: Measured at month 0 and 12
Measured by a commercial lab (Medstar, IL)
Measured at month 0 and 12

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Illinois at Chicago

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Krista Varady, PhD, University of Illinois at Chicago

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

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 1, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 28, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 30, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 5, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2020-1512
  • R01DK128180 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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