Time-restricted Feeding and Health (e-TRF)

March 26, 2026 updated by: Konstantinos Anastasiou, Harokopio University

The Effect of Early Time-restricted Feeding in Metabolic Health - Differences Between Chronotypes.

The purpose of this pilot, single-arm clinical trial is to assess the effects of time-restricted feeding on overall health, including body composition, glycemic and lipidemic profile, as well as appetite-regulating hormones, including glucagon-like peptides 1(GLP-1) oxyntomodulin, glucagon. Additionally, the study aims to evaluate the impact of this dietary pattern on circadian rhythm parameters, including acrophase, mesor, and amplitude.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

16

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

  • Greece
    • Attica
      • Athens, Attica, Greece, 17676
        • Harokopio University of Athens

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

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy men or women aged 18-35 years
  • Habitual daily eating window >10 hours
  • Stable body weight over the past 3 months (< ±10% change)
  • Able to provide informed consent independently

Exclusion Criteria:

  • Night shift work more than once per week
  • Presence of chronic diseases (e.g., cancer, renal or hepatic disease, inflammatory bowel disease, hypertension, diabetes, cognitive or psychiatric disorders)
  • Eating disorders
  • Use of medications affecting the intervention (e.g., corticosteroids, antidiabetics)
  • Pregnancy or planning pregnancy within the next 12 months
  • Diagnosis of insomnia

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: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Time-Restricted Feeding
Participants followed a four-week regimen of ad libitum food intake from 08:00 to 18:00, followed by a 14-hour fasting period until 08:00 the next day, while maintaining habitual physical activity and sleep patterns.
Other: Time-Restricted Feeding
Ad libitum food intake from 08:00 to 18:00, followed by fasting from 18:00 to 08:00 for four weeks. Outside the eating window, water and limited amounts (1-2 servings) of very low-calorie items (e.g., tea, diet soft drinks, coffee, chewing gum <4 kcal/serving) were permitted. The intervention focused exclusively on the timing of food intake and did not impose restrictions on the quantity or type of foods consumed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes from baseline in appetite-regulating hormones , including GLP-1 in pg/mL, oxyntomodulin in pg/mL, and glucagon in pg/mL at week 4, measured by ELISA kits.
Time Frame: Baseline and Week 4
Participants arrived at the laboratory between 08:30 and 09:00. An antecubital catheter was placed, and five blood samples were collected at fasting (0 min) and at 30, 60, 90, and 120 minutes after consuming the test meal. The test meal consisted of 100 g of S-Core FLEX Compact Protein powder (40 g carbohydrate, 29 g protein, 19 g fat) dissolved in 250 mL of water, providing 475 kcal.
Baseline and Week 4

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes from baseline in circadian rhythm parameters (acrophase in degrees of Celcious, mesor in time units, amplitude in degrees of Celcious) at week 4, measured through continouous measurements in skin termperature by a thermistor.
Time Frame: Baseline and Week 4
Participants wore a wireless skin temperature sensor (Thermochron iButton® DS1921-F5) on the palmar surface of the wrist of the non-dominant hand for 2 consecutive days. Circadian rhythmicity was analyzed using Cosinor analysis, which applies the least-squares method to fit the chronobiological data to cosine functions with predetermined periods of 12 and 24 hours.
Baseline and Week 4
Changes from baseline in Body Composition, namely fat free mass in kg and fat mass in kg
Time Frame: Baseline and week 4
Participant's body composition measurement pre/post time restricted feeding protocol
Baseline and week 4
Changes from Baseline in Glycemic and Lipidemic Profile, assessed by photometry.
Time Frame: Baseline and Week 4
Biochemical measurements in blood.
Baseline and Week 4

Collaborators and Investigators

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

Sponsor

Harokopio University

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)

June 4, 2025

Primary Completion (Actual)

December 16, 2025

Study Completion (Actual)

December 16, 2025

Study Registration Dates

First Submitted

January 15, 2026

First Submitted That Met QC Criteria

March 26, 2026

First Posted (Actual)

April 1, 2026

Study Record Updates

Last Update Posted (Actual)

April 1, 2026

Last Update Submitted That Met QC Criteria

March 26, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • Γ-1936/02-05-2025

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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