Study of the Effects of Time-Restricted Feeding on the Immune Function of Individuals With Obesity (OBESIMM)

Exploring the Effects of Time-restricted Feeding on the Immune Function of Obese Individuals: Multi-omic Approach

The goal of this randomized trial is to: 1) investigate the immunological landscape of patients with obesity and conduct an in-depth functional characterization of their immune system; and 2) precisely define the effects of time-restricted feeding (TRF) on immune function in patients with obesity; 3) uncover the underlying mechanisms by which TRF modulates the immune system patients with obesity through a multi-omics approach.

The main questions it aims to answer are: i) what is the underlying cause of impaired immunocompetence in patients with obesity? ii) how nutritional interventions improve the immune function of patients with obesity? Patients with obesity following TRF (8 h eating window ranging from 6-8 am to 14-16 pm) will be compared to patients with obesity without TRF control schedule (14h eating window ranging from 6-8 am to 8-10 pm). In addition to patients with obesity, the present study aims to recruit a group of a reference healthy group (BMI between 18.5-24.9 kg/m²) that will not receive any nutritional intervention.

The following endpoints will be collected: Body weight and composition using Bioelectrical Impedance Analysis, resting energy expenditure (REE) using indirect calorimetry, blood glucose levels using a continuous glucose monitoring (CGM) device, metabolic parameters (fasting blood glucose levels, C-peptide, HbA1c, insulin, HOMA-IR, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, hepatic enzymes), and cytokine profile.

Blood and stool, samples will be collected to establish metagenomic, transcriptomic, cytomic and metabolomic analyses.

Study Overview

• Status: Recruiting
• Conditions: Obesity and Obesity-related Medical Conditions
• Intervention / Treatment: Other: Time-restrictred feeding; Other: Non-time restricted feeding

• Study Type: Interventional
• Enrollment (Estimated): 24
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Cléo BOURGEOIS; Phone Number: +33 0156095638; Email: cleo.bourgeois@aphp.fr
• Study Contact Backup: Name: Sébastien CZERNICHOW, MD; Phone Number: +33 0156093067; Email: sebastien.czernichow@aphp.fr

Study Locations

• France
  • Paris, France, 75015
    • Active, not recruiting
    • HEGP - digestive surgery
  • Paris, France, 75015
    • Recruiting
    • HEGP - nutrition department
    • Principal Investigator: Sebastien CZERNICHOW
    • Contact: Sébastien CZERNICHOW; Phone Number: +33 0156093067; Email: sebastien.czernichow@aphp.fr
    • Contact: Nathalie ALRASSY; Email: nathalie.alrassy@aphp.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Patients with obesity

• Women
• Age 18-64 years
• Body mass Index between 40-50 kg/m²
• Self-reported eating pattern window of more than 14h
• Three meal eating pattern
• Stable body weight (less than 10% of current body weight during the last 3 months)
• Social security affiliation
• Written consent
• Good understanding of the French language

Lean patients

• Women
• Age 18-64 years
• Body mass Index between 18.5-24.9 kg/m²
• Self-reported eating pattern window of more than 14h
• Social security affiliation
• Written consent
• Good understanding of the French language

Exclusion Criteria:

• Diabetes type I or II
• Major cardiovascular disease
• Pregnancy
• Medication that could affect the study outcomes (i.e. anti-inflammatory drugs, antibiotics, immunosuppressors)
• Use products intended for weight loss
• Night work shift
• Past record of malignant tumors
• Serious liver dysfunction or chronic kidney disease
• Eating disorders
• Chronic viral disease (Hepatitis B or C, HIV) or inflammatory systemic diseases (i.e. Crohn's disease, rheumatoid arthritis)
• Serious cardiovascular or cerebrovascular disease within 6 months before randomization
• Severe gastrointestinal diseases or gastrointestinal surgery in the 12 months before randomization
• Under guardianship, curatorship, deprived of liberty
• Unable or unwilling to sign the informed consent form.
• Patient on AME (state medical aid)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control; Women with a healthy body weight without any dietary intervention
Experimental: Time-restricted feeding; Women with grade 3 obesity (BMI 40-50 kg/m²) follow a time-restricted feeding (TRF) pattern consisting of an 8 h eating window (from 6-8 am to 14-16 pm) followed by a 16 h fasting period.	Other: Time-restrictred feeding; Time-restricted feeding pattern consisting of an 8 h eating window (from 6-8 am to 14-16 pm) followed by a 16 h fasting period
Experimental: Non-Time restricted feeding; Women with grade 3 obesity (BMI 40-50 kg/m²) follow a 14h eating window (from 6-8 am to 8-10 pm), followed by a 10 h fasting period.	Other: Non-time restricted feeding; 14h eating window (from 6-8 am to 8-10 pm), followed by a 10 h fasting period

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Level of inflammatory cytokine IL-1β	The mean difference in inflammatory cytokine IL-1β in patients with obesity after 10 weeks under TRF versus patients with obesity without TRF.	10 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Change in fasting blood glucose levels from baseline	Baseline, 10 weeks
Change in fasting insulin levels from baseline	Baseline, 10 weeks
Change in HOMA-IR from baseline	Baseline, 10 weeks
Percent of weight change from baseline	Baseline, Week 10
Change in lean mass (expressed in kg), measured using Bioelectrical Impedance Analysis from baseline	Baseline, Week 10
Change in fat mass (expressed in kg), measured using Bioelectrical Impedance Analysis from baseline	Baseline, Week 10
Change in resting energy expenditure (kcal/day), measured using indirect calorimetry, from baseline	Baseline, 10 weeks
Change in fasting C-peptide levels from baseline	Baseline, 10 weeks
Change in HbA1c Levels from Baseline (Percentage Points)	Baseline, 10 weeks
Change in lipid profile from baseline	Baseline, 10 weeks
Change in ALT and AST levels (U/L) from baseline	Baseline, 10 weeks
Change in Plasma Cytokine Levels from Baseline Using Luminex Assay	Baseline, 10 weeks
Changes in blood metabolome evaluated by gas chromatography and liquid chromatography coupled with high-resolution mass spectrometry	Baseline, 10 weeks
Changes in gut microbiome diversity using shotgun metagenomics	Baseline, 10 weeks
Changes in gene expression profile assessed by RNA sequencing	Baseline, 10 weeks
Changes in blood immune cell populations measured using spectral flow cytometry	Baseline, 10 weeks

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Collaborators: National Research Agency, France

Study record dates

Study Major Dates

• Study Start (Actual): November 3, 2025
• Primary Completion (Estimated): September 15, 2027
• Study Completion (Estimated): September 15, 2027

Study Registration Dates

• First Submitted: March 13, 2025
• First Submitted That Met QC Criteria: March 26, 2025
• First Posted (Actual): March 28, 2025

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 20, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; Immune system
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: APHP230714; 2023-A01185-40 (Other Identifier: Agence nationale de sécurité du médicament et des produits de santé); 24.04388.000237 (Other Identifier: Commission Nationale des Recherche Impliquant la Personne Humaine)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data (IPD) that underlie results in publication could be shared. IPD detailed in the protocol of a planned metaanalysis could be shared
• IPD Sharing Time Frame: Two years after the last publication
• IPD Sharing Access Criteria: Data sharing must be accepted by the sponsor and the PI based on a scientific project and scientific involvement of the PI team. Collaboration will be fostered. The founder could be involved in the decision. Teams wishing obtain IPD must meet the sponsor and IP team to present scientifics (and commercial) purpose, IPD needed, format of data transmission, and timeframe. Technical feasibility and financial support will be discussed before mandatory contractualization. Processing of shared data must comply with European General Data Protection Regulation (GDPR).
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No