An interventional study of 60-hour Fasting and 12-hour Overnight Fasting (control) in Insulin Resistance and Fasting-Induced Insulin Resistance, sponsored by German Diabetes Center. Not yet recruiting. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by German Diabetes Center · Not applicable, Interventional, and Basic science
During prolonged fasting, the body shifts from using glucose toward using fat as its main energy source. At the same time, skeletal muscle becomes less sensitive to insulin, a hormone that helps regulate blood glucose levels. Although this response is a normal adaptation to fasting, the mechanisms responsible for it are not fully understood.
The DELIVER study aims to investigate how changes in fat metabolism, communication between tissues, and liver energy metabolism contribute to reduced insulin sensitivity during prolonged fasting.
In this randomized crossover study, 18 healthy adults will complete two conditions in random order: a 60-hour fasting period and a control condition involving a standard overnight fast. The conditions will be separated by at least four weeks.
During both conditions, researchers will assess insulin sensitivity, energy metabolism, and fat metabolism using blood and urine samples, magnetic resonance spectroscopy (MRS), measurements of energy expenditure, and small samples of skeletal muscle and abdominal fat tissue (biopsies). Insulin sensitivity will be measured using a hyperinsulinemic-euglycemic clamp, a procedure in which insulin and glucose are administered intravenously while blood glucose levels are closely monitored.
By comparing the two conditions, the study aims to improve understanding of how the body adapts to fasting and whether some of the mechanisms involved resemble those observed in insulin resistance associated with obesity and type 2 diabetes.
DELIVER is a single-center, randomized crossover study investigating the molecular and physiological mechanisms of insulin resistance induced by prolonged fasting. The study will enroll 18 healthy, sedentary men and women aged 18-40 years with a body mass index of 20-25 kg/m².
Each participant will undergo two experimental conditions in randomized order, separated by a washout period of at least four weeks: a 60-hour fasting condition and a control condition following a standard 12-hour overnight fast.
The primary objective is to determine whether fasting-induced skeletal muscle insulin resistance is associated with the accumulation of specific diacylglycerol (DAG) stereoisomers in distinct intracellular compartments, activation of protein kinase C (PKC) isoforms, and alterations in insulin signalling. Alternative mechanisms involving ceramides and PKCζ will also be investigated.
Secondary objectives include evaluating changes in adipose tissue metabolism and extracellular vesicle lipid cargo, assessing the effects of adipose tissue-derived extracellular vesicles on insulin sensitivity in cultured human skeletal muscle cells, and characterizing hepatic energy metabolism and insulin sensitivity during fasting. Potential sex differences will be examined as an exploratory objective.
Insulin sensitivity will be assessed using a two-step hyperinsulinemic-euglycemic clamp with stable glucose isotope tracers, allowing assessment of hepatic, adipose tissue, and peripheral insulin sensitivity. Skeletal muscle and subcutaneous abdominal adipose tissue biopsies will be obtained for lipidomic, molecular, mitochondrial, and extracellular vesicle analyses. Magnetic resonance spectroscopy will be used to assess skeletal muscle and liver lipid content and energy metabolism. Indirect calorimetry, blood sampling, 24-hour urine collection, continuous glucose monitoring, and physical activity monitoring will provide additional information on metabolic adaptations.
The crossover design allows each participant to serve as their own control. By integrating tissue-specific molecular analyses with measurements of whole-body metabolism, DELIVER aims to determine whether fasting-induced insulin resistance involves mechanisms similar to those implicated in obesity-associated insulin resistance or represents a distinct physiological adaptation.
2,969 studies on the registry are indexed under Insulin Resistance; 338 are open to participants now.
This study's planned enrollment of 18 is below the median of 40 across 2,369 interventional studies indexed under Insulin Resistance.
Browse Insulin Resistance studies →German Diabetes Center is the lead sponsor of 30 studies on the registry; 8 are open to participants now.
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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.
Able to provide signed and dated written prior to any study-specific procedures
For women specifically:
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants undergo 60 hours of complete fasting under medical supervision. At the end of the fasting period, insulin sensitivity and metabolic responses are assessed using a two-step hyperinsulinemic-euglycemic clamp, stable isotope tracers, magnetic resonance spectroscopy, indirect calorimetry, blood and urine sampling, and skeletal muscle and subcutaneous adipose tissue biopsies.
Other: 60-hour Fasting
Participants undergo a standard 12-hour overnight fast before metabolic assessments, without prolonged fasting. The same principal metabolic and tissue assessments are performed as in the prolonged fasting condition, allowing within-participant comparison of insulin sensitivity, tissue lipid metabolism, and molecular responses.
Other: 12-hour Overnight Fasting (control)
Participants undergo a 60-hour fasting period under medical supervision, during which water and broth are permitted according to the study protocol. The fasting period is followed by standardized metabolic assessments, including a two-step hyperinsulinemic-euglycemic clamp.
Standard overnight fasting for approximately 12 hours before metabolic assessments, serving as the control condition for comparison with prolonged fasting.
Skeletal muscle plasma membrane sn-1,2-diacylglycerol content
Difference in plasma membrane-associated sn-1,2-diacylglycerol (DAG) stereoisomer content in skeletal muscle between the 60-hour fasting condition and the control condition, assessed in basal vastus lateralis muscle biopsies.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Skeletal muscle DAG content in mitochondrial/endoplasmic reticulum and cytosolic fractions
Difference in sn-1,2-diacylglycerol content in mitochondrial/endoplasmic reticulum and cytosolic fractions of basal skeletal muscle biopsies between fasting and control conditions
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Skeletal muscle PKC translocation
Difference in PKCθ, PKCε and PKCζ translocation, assessed as membrane-to-cytosol ratios in basal skeletal muscle biopsies between conditions
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Skeletal muscle insulin signalling phosphorylation
Difference in basal and insulin-stimulated phosphorylation of insulin receptor (Tyr1162/1163), IRS-1 (Tyr612, Ser307, Ser1101), Akt (Ser473, Thr308), TBC1D4 (Thr642), GSK3β (Ser9) and S6K1 (Thr389) between conditions
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Skeletal muscle ceramide content and ratio
Difference in skeletal muscle ceramide content and ceramide ratios between fasting and control conditions
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Whole-body insulin sensitivity
Difference in whole-body insulin sensitivity, expressed as M/I (glucose infusion rate corrected for changes in the glucose pool, divided by steady-state plasma insulin), during the last 30 minutes of the high-dose insulin step of the two-step hyperinsulinemic-euglycemic clamp, between fasting and control conditions.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Insulin-induced suppression of endogenous glucose production
Difference in percentage suppression of EGP during the low-dose insulin step of the clamp, relative to basal EGP, between fasting and control conditions.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Insulin-induced suppression of plasma NEFA
Difference in percentage suppression of plasma non-esterified fatty acids (NEFA) during the low-dose insulin step of the clamp, relative to basal NEFA, between fasting and control conditions.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Insulin clearance
Difference in insulin clearance, calculated as insulin infusion rate divided by the steady-state increment in plasma insulin above baseline during the clamp, between fasting and control conditions.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Skeletal muscle intramyocellular lipid content
Difference in intramyocellular lipid (IMCL) content in the tibialis anterior muscle, assessed by ¹H-magnetic resonance spectroscopy, between fasting and control conditions.
Time frame: On the day before the clamp in each study condition, in both crossover periods: Day 1 of the control condition, and Day 3 of the fasting condition, after approximately 42 hours of fasting.
Hepatic ATP concentration
Difference in absolute hepatic γ-ATP concentration, assessed by ³¹P-magnetic resonance spectroscopy, between fasting and control conditions.
Time frame: On the clamp day of each study condition, before the start of insulin infusion, in both crossover periods: Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Adipose tissue transcriptomics
Differences in adipose tissue gene expression profiles, assessed by transcriptomic analysis of subcutaneous abdominal adipose tissue biopsies, between fasting and control conditions.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Adipose tissue-derived extracellular vesicle lipid content
Difference in diacylglycerol and ceramide content of extracellular vesicles isolated from subcutaneous abdominal adipose tissue biopsies, assessed by lipidomic profiling, between fasting and control conditions.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Sex-by-condition interaction for skeletal muscle plasma membrane DAG content
Exploratory comparison of the fasting-induced change in plasma membrane sn-1,2-DAG content between men and women (sex-by-condition interaction), reported with effect sizes and confidence intervals.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Sex-by-condition interaction for whole-body insulin sensitivity
Exploratory comparison of the fasting-induced change in M/I between men and women (sex-by-condition interaction), reported with effect sizes and confidence intervals.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
Sex-by-condition interaction for suppression of endogenous glucose production
Exploratory comparison of the fasting-induced change in percentage EGP suppression during the low-dose insulin step between men and women (sex-by-condition interaction), reported with effect sizes and confidence intervals.
Time frame: At the end of each study condition in both crossover periods (washout of at least 4 weeks): Day 2 of the control condition, after a 12-hour overnight fast, and Day 4 of the fasting condition, after 60 hours of fasting.
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Start is estimated for Jan 2027; primary completion for Jan 2028, 12 months later.
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 12 months is below 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.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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German Diabetes Center