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Completed

NCT Number: NCT07303036

Chronobiological Determinants of Gut Microbiome

The aim of this study is to examine how the number of daily eating occasions and the timing of energy intake influence gut microbiome composition in both morbidly obese and non-obese individuals. The analysis is based on baseline data from a case-control study involving 11 non-obese and 23 morbidly obese adults. Participants were excluded if they were younger than 19 or older than 65 years, had an acute or chronic inflammatory condition, had been diagnosed with an infectious disease, cancer, or alcohol dependence, or had used antibiotics within the three months prior to screening.

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Key information

Conditions

Morbid Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Obesity, Morbid Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

26 year–60 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Hacettepe University

Ankara, Turkey (Türkiye)

About this study

This study aimed to investigate how the number of daily eating occasions and the timing of energy intake influence gut microbiome composition in morbidly obese and non-obese adults. This case-control study examined the gut microbiota of 23 morbidly obese individuals (BMI > 40 kg/m²) and 11 non-obese individuals (BMI < 30 kg/m²).

Dietary intake was assessed using 24-hour dietary recall records. From these data, the number of meals, total daily energy intake, and the proportion of energy consumed within specific time intervals (06:00-13:00, 13:00-20:00, and 20:00-06:00) were calculated. Energy intake occurring after 20:00 was defined as nighttime eating.

Participant eligibility required individuals to be between 19 and 65 years of age, free from acute or chronic inflammatory diseases, and without diagnoses of infectious diseases, cancer, or alcohol addiction. Additionally, participants were excluded if they had taken antibiotics within the three months preceding the screening.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Adults aged 19 to 65 years Morbid obesity (case group) Non-obese status, including lean or pre-obese (control group) Willingness to participate in the study Ability to provide informed consent

Exclusion criteria

Age < 26 years or > 60 years Presence of acute or chronic inflammatory diseases Diagnosis of infectious diseases History of cancer Alcohol addiction Use of antibiotics within 3 months prior to screening

Treatment and study plan

Primary outcomes

  1. Gut microbial profiles of participants

    Time frame: Baseline

    Gut microbial profiles of participants at phylum and sub-phylum levels

  2. Meal frequency of participants

    Time frame: Baseline

    Number of meals consumed per day

  3. Total daily energy intake

    Time frame: Baseline

    Total daily energy intake assessed from dietary data (kcal/day)

  4. Distribution of energy intake by time of day

    Time frame: Baseline

    Percentage of total daily energy intake consumed during predefined time periods of the day (e.g., morning, afternoon, evening, night)

Sponsors and collaborators

Lead sponsor

Hacettepe University

Other

Registry information

Official study title

Chronobiological Determinants of Gut Microbiome: The Effects of Meal Timing and Eating Frequency

Acronym: ChronoNutr

Important dates

Study start
2016
Primary completion
2018
Study completion
2019
First posted
Dec 24, 2025
Registry last updated
Dec 24, 2025

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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