The Effect of Fasting on Peak Fat Oxidation, Mitochondrial Coupling and Extracellular Matrix

NCT07692646 | Recruiting

• 1 other identifier: Molecular Memory of Obesity
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

The interventional study will recruit four groups (n=10 per group): Young men and women with normal weight (BMI 18-25), and young men and women with obesity (BMI \>30). The study will investigate the effect of 84 hours of fasting on peak fat oxidation, mitochondrial coupling and the extracellular matrix.

Conditions

Fasting; Sex Difference; Obesity (BMI>30)

Keywords

Muscle metabolism; Mitochondrial coupling; Extracellular matrix composition; Peak fat oxidation

Outcome Measures

Primary Outcomes (1)

• The effect of fasting and obesity on protein glycosylation of the extracellular matrix in adipose tissue

  The composition and protein glycosylation of the extracellular matrix will be measured in abdominal subcutaneous adipose tissue samples in 20 healthy normal weight men and women and 20 healthy obese men and women.

  The fasting will last approximately 84 hours.

Secondary Outcomes (1)

• The effect of fasting and obesity on peak fat oxidation

  The fasting will last approximately 84 hours

Other Outcomes (1)

• The effect of fasting and obesity on adipose tissue lipolytic capacity, muscle ketone oxidative capacity and mitochondrial coupling.

  The fasting will last approximately 84 hours.

Study Arms (4)

Young normal weight men

EXPERIMENTAL

BMI \[18, 25\] Age \[18, 40\]

Other: Diet

Young normal weight women

EXPERIMENTAL

BMI \[18, 25\] Age \[18, 40\]

Other: Diet

Young obese men

EXPERIMENTAL

BMI \[30, 40\] Age \[18, 40\]

Other: Diet

Young obese women

EXPERIMENTAL

BMI \[30, 40\] Age \[18, 40\]

Other: Diet

Interventions

Diet OTHER

Long-term fasting (84 hours), physiological testing before and after fasting: sampling of blood, abdominal adipose tissue and skeletal muscle for molecular analysis and respiratory measurements at rest.

Young normal weight men; Young normal weight women; Young obese men; Young obese women

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy normal weight men aged \[18,40\] and BMI \[18,25\]
• Healthy normal weight women \[18,40\] and BMI \[18,25\]
• Healthy obese men \[18,40\] and BMI \[30,40\]
• Healthy obese women \[18,40\] and BMI \[30,40\]

You may not qualify if:

• Present or former cardiovascular disease and chronical inflammatory disease
• Consumption of medications and supplements that influence substrate use at rest and/or during exercise
• Pregnancy

Sponsors & Collaborators

• University of Copenhagen: lead

Study Sites (1)

Department of Biomedical Sciences

Copenhagen, 2200, Denmark

RECRUITING

MeSH Terms

Conditions

Fasting; Obesity

Interventions

Diet

Condition Hierarchy (Ancestors)

Feeding Behavior; Behavior; Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Central Study Contacts

Jørn W Helge, PhD

CONTACT

+4528757506; jhelge@sund.ku.dk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: Cross sectional study including four groups

Study Record Dates

• First Submitted: June 19, 2026
• First Posted: July 9, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): December 1, 2033
• Last Updated: July 9, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, CSR
• Time Frame: The data will be available after publication and indefinately
• Access Criteria: Not known at this state

Locations

DK (1)