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ObesityNCT04692532

Time Restricted Eating for Weight Management

A study testing 8-hour Time restricted eating and Calorie restriction in people with Obesity, run by University of Illinois at Chicago at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

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. Read more about this study

Who is it for?
Ages 18 to 65 yearsHealthy volunteers can take part
Conditions the study is for
Obesity
What is being tested?
8-hour Time restricted eating and Calorie restriction
Could I receive a placebo?
No, everyone receives an active treatment
How many people
90 participants
Where
1 siteUnited States
Study dates
1 Jan 2021to 1 Feb 2025
Phase
Interventional
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 65 years
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • 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)

Who cannot join

  • • 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)
Show all 10Show fewer
  • Are eating within less than a 10-hour window at baseline
  • Are pregnant, or trying to become pregnant
  • Are night shift workers
  • Are smokers

Trial locations and contacts

1 site in 1 country.

United States1 site

  • University of Illinois Chicago

    Chicago, Illinois, 60612

Other trials in United States

About this study

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.

Read the 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.

Conditions
Obesity
Being tested
8-hour Time restricted eating, Calorie restriction
Medical subject headings
Obesity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 8-hour Time restricted eatingOther

    Ad libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)

  • Calorie restrictionOther

    25% energy restriction every day

Study groups in NCT04692532
Study groupRoleWhat they receive
8-hour Time restricted eatingExperimentalAd libitum food intake from 12-8 pm every day Fasting from 8-12 pm every day (16-h fast)
Receives: Other: 8-hour Time restricted eating
Calorie restrictionExperimental25% energy restriction every day
Receives: Other: Calorie restriction
ControlNo interventionUsual diet, Ad libitum intake, eating within >10 hours per day

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Body Weight

    Measured by an electronic scale

    Measured: Measured at month 0 and 12

Secondary outcomes (9)

  1. Change in Fat Mass

    Measured by DXA

    Measured: Measured at month 0 and 12

  2. Change in Insulin Resistance

    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: Measured at month 0 12

  3. Change in Insulin Sensitivity

    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: Measured at month 0 and 12

  4. Change in Fasting Glucose

    Measured by a commercial lab (Medstar, IL)

    Measured: Measured at month 0 and 12

  5. Change in HbA1c

    Measured by a commercial lab (Medstar, IL)

    Measured: Measured at month 0 and 12

  6. Change in Fasting Insulin

    Measured by a commercial lab (Medstar, IL)

    Measured: Measured at month 0 and 12

  7. Change in Systolic Blood Pressure

    Measured by a blood pressure cuff

    Measured: Measured at month 0 and 12

  8. Change in Diastolic Blood Pressure

    Measured by a blood pressure cuff

    Measured: Measured at month 0 and 12

  9. Change in LDL Cholesterol

    Measured by a commercial lab (Medstar, IL)

    Measured: Measured at month 0 and 12

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted5 Jan 2021
  2. Study start1 Jan 2021
  3. Primary completion1 Feb 2025
  4. Study completion1 Feb 2025

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Single blind
Who is masked
Outcomes assessor
Enrolment
90 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04692532
Sponsor's protocol ID
2020-1512
Other IDs
R01DK128180
Status last verified
Jul 2026
First submitted
28 Dec 2020
Last updated
27 Jul 2026
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Publications

  • Lin S, Cienfuegos S, Ezpeleta M, Pavlou V, Runchey MC, Varady KA. Effect of time restricted eating versus daily calorie restriction on sex hormones in males and females with obesity. medRxiv [Preprint]. 2024 May 15:2024.05.15.24307415. doi: 10.1101/2024.05.15.24307415.

    PubMed 38798539

  • Lin S, Cienfuegos S, Ezpeleta M, Gabel K, Pavlou V, Mulas A, Chakos K, McStay M, Wu J, Tussing-Humphreys L, Alexandria SJ, Sanchez J, Unterman T, Varady KA. Time-Restricted Eating Without Calorie Counting for Weight Loss in a Racially Diverse Population : A Randomized Controlled Trial. Ann Intern Med. 2023 Jul;176(7):885-895. doi: 10.7326/M23-0052. Epub 2023 Jun 27.

    PubMed 37364268

Questions about this trial

What is this clinical trial studying?

A study testing 8-hour Time restricted eating and Calorie restriction in people with Obesity, run by University of Illinois at Chicago at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 27 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 27 Jul 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Body Weight (time frame: Measured at month 0 and 12). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04692532, which also lists 2 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Jul 2026.

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Time Restricted Eating for Weight Management | AzTrials