An interventional study of Diet in Fasting, Obesity (BMI>30) and Sex Difference, sponsored by University of Copenhagen. Recruiting at 1 site in Denmark. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-09.
Sponsored by University of Copenhagen · Not applicable, Interventional, and Basic science
Among 10 studies in Fasting with a site in Denmark — 3 open to participants now, 3 under way, none of them phase 3. Fasting · Denmark.
Among the 10 studies in Fasting with a site in Denmark, this one is the only one that started in 2026, is one of 9 with no phase, and was the 10th registered.
392 studies on the registry are indexed under Fasting; 63 are open to participants now.
Browse Fasting studies →3 of the 10 studies in Fasting with a site in Denmark are open now. Recruiting first, the newest first:
Steno Diabetes Center Copenhagen · Sites in Denmark
University of Southern Denmark · Sites in Denmark
A study can be open while its sites in Denmark have not opened yet or have stopped. Only those recruiting at a site in Denmark →
Of the 45 Fasting studies recruiting now, 15 (33%) set no upper age limit and 24 (53%) stop at 75 or younger; 7 take children under 18; 20 take healthy volunteers.
This study: 18 Years to 40 Years · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
10 studies; the count open now beside each. This study's row is marked.
First in 2005; this study’s year is marked. 1 started in 2026.
This study's planned enrollment of 40 is below the median of 45 across 311 interventional studies indexed under Fasting.
Median enrollment 10 across the 9 interventional studies, 15,000 across the 1 observational. Of the 7 that completed or were terminated, 0 (0%) have results posted.
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None of the 10 has an industry lead sponsor. The 6 most frequent:
University of Copenhagen is the lead sponsor of 466 studies on the registry; 64 are open to participants now.
University of Copenhagen has 1 study filed under Fasting — fewer than ten, so there is no comparison to draw.
1 of the studies in Fasting with a site in Denmark that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07692646University of CopenhagenThe Effect of Fasting on Peak Fat Oxidation, Mitochondrial Coupling and Extracellular Matrix | 2027-08 |
Among the 10 studies in Fasting with a site in Denmark, from their registry updates:
Nothing recorded among them since 2026-09-25.
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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.
Four groups of young normal weight men (n=10) and women (n=10) and young obese men (n=10) and women (10) are recruited. After verbal and written information is provided signed consent is obtained.
Prior to the first day of the trial, the participants must complete a four-day dietary and exercise record based on the weighing of all food and beverages consumed and tracking all exercise. This is used to asses the participant's habitual diet and activity level. For female participants, an additional form must be completed regarding their menstrual cycle and form of contraception.
On the two trial days (before and after fasting), participants arrive at the laboratory in the morning, and on the first day, the participant will have fasted since the previous evening. Furthermore, participants have been asked to minimize strenous physical activity for 24 hours leading up to testing. Prior to day 1, participants have been instructed to consume a habitual carbohydrate-rich diet for the 48 hours preceding the first test day.
Initially, the participants' body composition is determined by DXA, after which the participants rest for 15 minutes. Subsequently, blood pressure is measured in the supine position whereafter resting energy expenditure is measured by indirect calorimetry. A venous blood sample is taken from the antecubital vein, as well as a biopsy from the m. vastus lateralis and from the subcutaneous abdominal adipose tissue using the Bergström technique applied with suction. After 30 minutes of rest, a graded exercise test on a cycle ergometer is initiated to determine peak fat oxidation and maximal oxygen uptake. After the test is completed and following a minimum of 10 minutes of rest, handgrip strength and knee extension strength are measured. This concludes the test day.
Thereafter, the 84-hour fast is initiated. During the fasting period, the subjects will communicate by telephone each morning with one of the researchers regarding their well-being and any questions they may have. On day 2 subjects will do 1 hour of submaximal exercise. During the fasting subjects will be provided with electrolyte tablets. Following the 84 hours, the subjects return to the laboratory. Here, the same protocol as described above is carried out. This concludes the test day and the experiment.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI \[18, 25\] Age \[18, 40\]
Other: Diet
BMI \[18, 25\] Age \[18, 40\]
Other: Diet
BMI \[30, 40\] Age \[18, 40\]
Other: Diet
BMI \[30, 40\] Age \[18, 40\]
Other: Diet
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.
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.
Time frame: The fasting will last approximately 84 hours.
The effect of fasting and obesity on peak fat oxidation
40 participants (20 healthy normal weight men and women and 20 healthy obese men and women) will fast for 84 hours. Before and after the fast, peak fat oxidation (mg fat/min) is measured in an incremental bike test using indirect calorimetry.
Time frame: The fasting will last approximately 84 hours
The effect of fasting and obesity on adipose tissue lipolytic capacity, muscle ketone oxidative capacity and mitochondrial coupling.
The lipolytic capacity will be measured in abdominal subcutaneous adipose tissue samples and the capacity for ketone oxidation in vastus lateralis muscle in 20 healthy normal weight men and women and 20 healthy obese men and women.and In addition mitochondrial respiratory capacity will be measured in the muscle and adipose biopsy samples using high-resolution respirometry (Oxygraphs, Oroboros).
Time frame: The fasting will last approximately 84 hours.
Plan to share: Yes — When the experiments are concluded and the paper(s) are accepted that data will be able upon reasonable request
Supporting information: Study protocol, Statistical analysis plan, Clinical study report
Time frame: The data will be available after publication and indefinately
Access criteria: Not known at this state
No publications or documents are linked to this record.
Start is estimated for Jun 2026; primary completion for Aug 2027, 14 months later.
Of 144 non-industry interventional studies with no phase under Fasting, half reached primary completion within 19 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 40. This study's planned 14 months is below that.
Counting every sponsor, half of 149 studies reached it within 18 months; a quarter within 6 and three quarters within 40.
How these figures are worked out, and which studies are left out of them.
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