An interventional study of Physical Inactivity and Hypercaloric High-Fat Diet in Metabolic Health and Insulin Sensitivity/Resistance, sponsored by University of Copenhagen. Recruiting at 1 site in Denmark. Open to participants aged 25 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-17.
Sponsored by University of Copenhagen · Not applicable, Interventional, and Basic science
The goal of this intervention study is to learn more about what causes insulin resistance in otherwise healthy adults, and how short-term changes in physical activity or diet may influence it. The study includes healthy male and female participants aged 25 to 55 years, who meet specific health criteria.
The main questions it aims to answer are:
Does the cause of insulin resistance vary between individuals due to their genes and lifestyle?
Can the investigators identify different types (sub-phenotypes) of insulin resistance at the molecular level?
Researchers will compare groups who either reduce their physical activity for 14 days or consume a high-fat diet for 3 days, to see how these changes affect insulin sensitivity and related biological markers.
Participants will:
This study will help researchers better understand how lifestyle and biology interact in the development of insulin resistance, even in people who are otherwise healthy.
This intervention study aims to uncover the molecular mechanisms that underlie insulin resistance in otherwise healthy adults and to explore how short-term lifestyle changes may influence these mechanisms. Insulin resistance is a key feature in the development of type 2 diabetes and other metabolic diseases, but it does not arise uniformly across individuals. The overarching hypothesis is that insulin resistance has multiple underlying causes that differ between individuals, depending on genetic variation and modifiable lifestyle factors such as physical activity and diet.
A total of 80 healthy participants-40 males and 40 females aged between 25 and 55 years-will be recruited. All participants must have a body mass index (BMI) between 18 and 30 and meet strict inclusion and exclusion criteria to minimize confounding variables. Participants will be free of chronic disease, non-smokers, have limited alcohol intake, and not engage in high levels of physical activity. This controlled approach ensures a more accurate assessment of the variables under investigation.
At baseline, all participants will undergo comprehensive phenotyping, including assessments of habitual physical activity, dietary intake, glucose tolerance, and whole-body insulin sensitivity. This will allow the researchers to categorize sub-phenotypes of insulin resistance at both the physiological and molecular level.
Following baseline testing, 40 of the 80 participants will undergo one of two short-term interventions designed to stress metabolic pathways associated with insulin sensitivity:
The aim of these interventions is to test how short-term negative lifestyle changes impact insulin action and related molecular markers, and whether these responses vary between individuals with different phenotypic and genetic profiles.
After the intervention period, selected metabolic tests will be repeated to assess changes in insulin sensitivity and molecular signaling. The primary outcome measure is whole-body insulin action, assessed using gold-standard physiological methods. Exploratory outcomes include identifying cellular and molecular mechanisms contributing to insulin resistance, and understanding the interaction between gene expression and lifestyle responses.
By combining deep phenotyping with short-term interventions, this study will generate new insights into the biological diversity of insulin resistance. Ultimately, this may contribute to the development of more individualized strategies for the prevention and treatment of metabolic diseases.
2,969 studies on the registry are indexed under Insulin Resistance; 338 are open to participants now.
This study's planned enrollment of 80 is above the median of 40 across 2,369 interventional studies indexed under Insulin Resistance.
Browse Insulin Resistance studies →University of Copenhagen is the lead sponsor of 466 studies on the registry; 64 are open to participants now.
Counted across the registry records on this site, refreshed daily.
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.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
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.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All participants (N=80) undergo extensive baseline characterization over three study visits. This includes assessments of insulin sensitivity, glucose tolerance, metabolic and physiological phenotyping, habitual physical activity, and dietary intake. No intervention is applied during this phase; the purpose is to establish baseline measures and characterize individual variation in insulin resistance and metabolic profiles. Participants complete detailed clinical, physiological, and behavioral assessments without any experimental manipulation. This includes: * Measurement of insulin action and glucose tolerance * Dietary and physical activity profiling * Collection of biospecimens for molecular analyses
A subset of 40 participants are randomized into one of two experimental interventions following baseline assessment: * 14 days of reduced physical activity (\<1,500 steps/day), or * 3 days of a hypercaloric high-fat diet The aim is to evaluate how short-term lifestyle stressors affect insulin sensitivity and related molecular markers. Assessments from visits 4 and 5 are compared to baseline to determine within-subject changes. Intervention Names: 1. Reduced Physical Activity \- Participants limit daily steps to \<1,500 for 14 days 2. High-Fat Diet * Participants consume a hypercaloric, high-fat diet for 3 days Description of Intervention: Participants undergo one of the two lifestyle interventions with strict monitoring and support. Selected baseline tests are repeated post-intervention to evaluate metabolic and molecular responses.
Behavioral: Physical Inactivity · Behavioral: Hypercaloric High-Fat Diet
Participants assigned to the physical inactivity intervention will reduce their daily physical activity to fewer than 1,500 steps per day for 14 consecutive days. This strict limitation significantly decreases overall movement and muscle activity, mimicking a sedentary lifestyle. The aim is to assess the short-term effects of reduced physical activity on insulin sensitivity and related metabolic processes. Compliance will be monitored using activity trackers and daily logs. Baseline metabolic and physiological assessments will be repeated after the intervention to evaluate changes.
Also known as: Reduced Activity
Participants assigned to the high-fat diet intervention will consume a hypercaloric diet rich in fat for 3 consecutive days. The diet is designed to significantly increase caloric intake and fat consumption beyond habitual levels to induce short-term metabolic stress. This intervention aims to assess how a brief period of high-fat overfeeding affects insulin sensitivity and related molecular pathways. Participants' dietary intake will be carefully controlled and monitored to ensure adherence. Baseline metabolic and physiological assessments will be repeated after the intervention to evaluate changes.
Also known as: Overeating
Whole-body insulin action
Glucose disposal rates during hyperinsulinemic euglycemic conditions as a marker of whole-body insulin action
Time frame: Baseline characterization & immediately following intervention (either 14 days of physical inactivity or 3 days of hypercaloric high-fat diet)
Identification of proteins and posttranslational modification of proteins in blood as well as skeletal muscle and adipose tissue biopsies
The obtained samples will be subjected to mass spectrometry-based proteomic and phosphoproteomic analyses. These measurements show protein abundance and posttranslational modifications that regulates protein function. Ultimately, revealing the signaling network underlying the interventions studied. Unit of measure is log2-transformed arbitrary units.
Time frame: Baseline & immediately following the intervention (14 days of physical inactivity or 3 days of hypercaloric high-fat diet)
Whole-Body Glucose Tolerance
Whole-body glucose tolerance will be assessed by an oral glucose tolerance test (OGTT). Blood glucose and insulin concentrations will be measured at multiple time points following oral glucose ingestion to determine glucose and insulin responses. Glucose and insulin areas under the curve (AUC) values will be used to evaluate changes in glucose tolerance.
Time frame: Baseline
Beta Cell Function
Beta cell function will be evaluated using an intravenous glucose tolerance test (IVGTT). Following intravenous glucose administration, arterial glucose and insulin concentrations will be measured at multiple time points to assess first-phase insulin secretion and beta cell responsiveness.
Time frame: Baseline & immediately following the intervention (14 days of physical inactivity or 3 days of hypercaloric high-fat diet)
Plan to share: No — Due to the sensitive nature of the physiological and molecular data collected, and the relatively small and deeply phenotyped cohort, there is a risk of re-identification. Participants have not provided explicit consent for public sharing of their individual data. Furthermore, data protection regulations under the EU General Data Protection Regulation (GDPR) place strict limitations on the sharing of personal data, particularly when it concerns health-related information. For these reasons, individual participant data will not be shared publicly. Data sharing may be considered in the future under controlled access with appropriate ethical approvals and data use agreements.
No publications or documents are linked to this record.
Started Jan 2026 (actual). Primary completion is estimated for Jun 2028, 29 months after the start.
Of 714 non-industry interventional studies with no phase under Insulin Resistance, half reached primary completion within 22 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 41. This study's planned 29 months is above that.
Counting every sponsor, half of 754 studies reached it within 21 months; a quarter within 9 and three quarters within 40.
How these figures are worked out, and which studies are left out of them.
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