Why Calories Are Not the Same - a Gut Explanation?

NCT ID: NCT06932666

Last Updated: 2025-12-26

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

60 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-05-15

Study Completion Date

2026-12-31

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

The aim of this study is to understand how the gut microbiome influences how much dietary energy humans excrete via feces. This study is based on the hypothesis that levels of methane in exhaled breath represent two different gut microbiome community structures, and therefore influence fecal energy excretion differently. Moreover, this study is assessed in the context of two different diets, both isocaloric and equal in macronutrient composition, but differing in contents of fiber, resistant starch, and large particles; which are hypothesized to impact the gut microbiome differently.

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

The trial is a cross-over trial including two controlled isocaloric dietary interventions of three days duration. The two diets are isocaloric but with different contents of fiber, resistant starch, and food particle sizes. Each intervention is separated by a wash-out period of at least 10 days where participants adhere to their habitual diet. The trial includes a total of five visits (one screening visit and four regular visits).

Before the trial, participants undergo a screening period of 4 days. During the 4-day screening period, participants measure the levels of methane in their exhaled breath. Based on median breath methane levels, participants are allocated to one of the two arms: (HMP: high methane producers; LMP: low methane producers). Enrollment in the intervention trial will be conducted so there are similar numbers of participants in both arms.

At the beginning and at the end of each 3-day intervention period, participants consume a blue muffin, containing a royal blue dye that changes the stool color. The appearance of the color in stool following the first muffin will mark the beginning of the stool collection period, which will continue until the stool color change is no longer noticeable following consumption of the second muffin. Therefore, the duration of the stool collection period, which is estimated to be on average 3 days, will ultimately depend on the participants' passage time of food (i.e., intestinal transit time).

During the screening period, participants are asked to:

* measure their methane and hydrogen levels in exhaled breath using a portable device
* report defecation patterns (including stool frequency and Bristol Stool Scale)

Before each intervention period, participants are asked to:

* collect a fecal and urine sample
* register three days of habitual diet

At the visits before each intervention period, the following samples are collected:

* a blood sample
* methane and hydrogen measurements in exhaled breath
* anthropometrics
* data on physical activity

During the intervention periods, participants are asked to:

* exclusively eat all the foods provided
* collect all their stool samples, as specified above
* collect three morning urine samples (one daily for the following three days)
* measure their methane and hydrogen levels in their exhaled breath using a portable device
* report their defecation patterns and gastrointestinal symptoms

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Diet, Healthy Breath Analysis

Keywords

Explore important study keywords that can help with search, categorization, and topic discovery.

Fecal energy Metabolizable energy Breath methane Gut microbiome Metabolomics Dietary fiber Resistant starch Food particle size

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

NON_RANDOMIZED

Intervention Model

CROSSOVER

Overall, there are two parallel arms - high- (HMP) and low- (LMP) methane producers, to which the participants are allocated in a ratio 1:1 after a 4-day screening period, where individual levels of methane in exhaled breath are measured multiple times.

In both arms, participants undergo two 3-days dietary interventions in a crossover design and separated by a +10-day washout period. Participants are randomized to receiving diet A first or diet B first. These two diets are isocaloric and equal in macronutrient composition, but differ on dietary fiber, resistant starch and food particle size.
Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

NONE

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

High-methane producers

Individuals exhaling high levels of methane (median exhaled methane \>= 5 ppm), as measured 3-times daily during the screening period.

Group Type EXPERIMENTAL

Diet A group

Intervention Type OTHER

Diet high in fiber (\> 40g/10MJ), high in resistant starch (\> 10g/10MJ), and containing large food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements.

Diet B group

Intervention Type OTHER

Diet low in fiber (\< 10g/10MJ), low in resistant starch (\< 3g/10MJ) and containing small food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements.

Low-methane producers

Individuals exhaling low levels of methane (median exhaled methane \< 5 ppm), as measured 3-times daily during the screening period.

Group Type EXPERIMENTAL

Diet A group

Intervention Type OTHER

Diet high in fiber (\> 40g/10MJ), high in resistant starch (\> 10g/10MJ), and containing large food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements.

Diet B group

Intervention Type OTHER

Diet low in fiber (\< 10g/10MJ), low in resistant starch (\< 3g/10MJ) and containing small food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements.

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Diet A group

Diet high in fiber (\> 40g/10MJ), high in resistant starch (\> 10g/10MJ), and containing large food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements.

Intervention Type OTHER

Diet B group

Diet low in fiber (\< 10g/10MJ), low in resistant starch (\< 3g/10MJ) and containing small food particles. Diet is provided for 3 full days, consists of three meals per day (breakfast, lunch, and dinner) and in-between meals, and covers 100% of the participants' energy requirements.

Intervention Type OTHER

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

* 18-65 years old
* BMI:18.5-29.9 kg/m2
* Self-reported regular defecations defined as at least every second day
* Willing to collect urine and stool samples at home and able to temporarily store them in their own freezer in a provided container
* Willing to exclusively eat the food provided
* Owning a smartphone (iOS 11.0 and onwards, or Android 5.0 and onwards) with access to the internet
* Speak and understand Danish or English

Exclusion Criteria

* Current pregnancy or lactation
* Following a specific dietary program or diet (e.g., vegetarian, vegan, gluten-free) or unable to consume the food provided
* Diagnosis of small intestinal bacterial overgrowth (SIBO), inflammatory bowel diseases (IBD), gastrointestinal obstruction, or ischemic colitis
* Diagnosed chronic constipation
* Regular use of diarrhea inhibitors or laxatives
* Any chronic disease that can affect the outcomes of the study
* Use of medications potentially altering gastric pH (proton pump inhibitors, histamine receptor antagonists, antacids)
* Use of medications potentially altering the gastro-intestinal motility (prokinetics, antiemetic agents, anticholinergic agents, narcotic analgesics, nonsteroidal anti-inflammatory drugs, peroral glucocorticoids, and GLP-1 related medications such as semaglutide and liraglutide)
* Use of antibiotics, or any medication that can affect any outcomes of the study, within the previous three months
* Concurrent participation in another trial
* Any condition that makes the project responsible and/or the clinical responsible doubt the feasibility of the volunteer's participation
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

Meet the organizations funding or collaborating on the study and learn about their roles.

Wageningen University and Research

OTHER

Sponsor Role collaborator

University of Copenhagen

OTHER

Sponsor Role lead

Responsible Party

Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.

Henrik Munch Roager

Associate Professor

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

Explore where the study is taking place and check the recruitment status at each participating site.

University of Copenhagen, Department of Nutrition, Exercise and Sports

Frederiksberg, Capital Region, Denmark

Site Status RECRUITING

Countries

Review the countries where the study has at least one active or historical site.

Denmark

Central Contacts

Reach out to these primary contacts for questions about participation or study logistics.

Henrik M Roager, PhD

Role: CONTACT

Phone: +45 35324928

Email: [email protected]

Facility Contacts

Find local site contact details for specific facilities participating in the trial.

Henrik M Roager, PhD

Role: primary

Other Identifiers

Review additional registry numbers or institutional identifiers associated with this trial.

M408

Identifier Type: -

Identifier Source: org_study_id