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Completed

NCT Number: NCT07505680

Time-restricted Feeding and Health

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.

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Key information

Conditions

Appetite Body Weight Control Circadian Rhythm Glycemic and Insulinemic Response Metabolic Health

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Harokopio University of Athens

Athens, Attica, 17676, Greece

Who can participate

Healthy volunteers accepted: Yes

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

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

Treatment and study plan

Time-Restricted Feeding

Other

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.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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

  3. Changes from Baseline in Glycemic and Lipidemic Profile, assessed by photometry.

    Time frame: Baseline and Week 4

    Biochemical measurements in blood.

Sponsors and collaborators

Lead sponsor

Harokopio University

Other

Registry information

Official study title

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

Acronym: e-TRF

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Apr 1, 2026
Registry last updated
Apr 1, 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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