Investigating how fasting affects energy expenditure in the body
Official title: Mechanisms of Fasting Induced Reduction in Energy Expenditure - FIRE Trial
Run by ETH Zurich · NCT06134258 · Data updated 2026-11-12
This study is testing how different fasting periods affect energy use in the body and how it relates to thyroid hormones in people who respond differently to fasting.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years to 40 Years |
| Sex | All |
| Enrollment | 40 (estimated) |
| Sponsor | ETH Zurich Academic / other |
| Locations | 1 site (Basel) |
| Status | Recruiting |
| Started | November 15, 2023 |
| Main results expected | April 18, 2026 |
| Study ends | April 18, 2026 |
| Registry record updated | May 30, 2025 |
| Trial ID | NCT06134258 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates for this study are healthy adults aged 18 to 40 with a body mass index between 18.0 and 27.0 kg/m².
✕Probably not a fit
Patients with chronic medical conditions requiring treatment, such as diabetes or cardiovascular disease, will not benefit from this study.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This research project aims to explore the mechanisms behind the body's adaptation to fasting, specifically how it affects basal metabolic rate. Initially, a preliminary study will measure the metabolic response of participants to a 24-hour fast. Those with varying responses will be invited to a main study where they will undergo either a 24-hour or an 8-hour fasting period, followed by a mixed meal test to assess energy metabolism and the role of thyroid hormones. The study will also involve taking samples of subcutaneous adipose tissue for further analysis.
Why it matters
Potential benefit: If successful, this study could provide insights into metabolic adaptations to fasting, potentially leading to improved dietary recommendations and interventions for weight management.
How similar studies have gone: While fasting has been studied in various contexts, this specific investigation into the metabolic adaptation mechanisms is relatively novel and has not been extensively tested.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Age: 18 to 40 years * Body mass index 18.0 to 27.0 kg/m² * Exclusion Criteria: * Chronic conditions necessitating medical treatment (e.g., renal failure, hepatic dysfunction, cardiovascular disease, diabetes mellitus), * Known or suspected non-compliance, drug or alcohol abuse, * Inability to follow the procedures of the study * Participation in another study with investigational drug within the 30 days preceding and during the present study, * Previous enrolment into the current study, * Enrolment of the investigator, his/her family members, employees and other dependent persons, * Hypothyroidism or hyperthyroidism * Pregnant, breastfeeding and menopausal women
Where it's running
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University Hospital Basel
Basel, Switzerland Recruiting
Study contacts
- Principal investigator: Matthias Betz — University Hospital, Basel, Switzerland
- Study coordinator: Matthias Betz
- Email: matthias.betz@usb.ch
- Phone: 0041 61 265 2525
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.