PrediabetesGLYCOTIMENCT07171281
Precise Eating Time to Improve Glycemic Control and Cardiometabolic Health in Prediabetes and Diabetes
A study testing Early Time-Restricted Eating and Late Time-Restricted Eating in people with Prediabetes and Type 2 Diabetes, run by German Institute of Human Nutrition at 1 site in Germany.
Trial summary
The objective of this study is to investigate the impact of hypocaloric time-restricted eating (TRE) at different day times (early versus late TRE) on glucose metabolism and other cardiometabolic parameters in individuals with overweight and with normal, or impaired glucose metabolism (prediabetes and type 2… Read more about this study
- Who is it for?
- Ages 18 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Prediabetes, Type 2 Diabetes, Obesity &Amp; Overweight
- What is being tested?
- Early Time-Restricted Eating and Late Time-Restricted Eating
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteGermany
- Study dates
- 1 Oct 2025to 28 Feb 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Overweight or obesity (BMI 25-40 kg/m²)
- Healthy glucose metabolism (fasting glucose <100 mg/dl and glucose after 2 hours OGTT <140 mg/dl)
- OR impaired glucose metabolism (fasting glucose 100-125 mg/dl and/or glucose after 2 hours OGTT 140-199 mg/dl and/or HbA1c 5.7-6.4%)
- OR type 2 diabetes (according to existing medical diagnosis or fasting glucose >126 mg/dl and/or glucose after 2 hours OGTT >200 mg/dl and/or HbA1c ≥6.5%)
- Daily eating window ≥12 hours
Who cannot join
- Weight changes > 5% within past 3 months
- Shift work
- Traveling across more than one time zone within one month prior to the study
- Pregnancy and breastfeeding
- Eating disorders, food intolerance/allergy to ingredients in the diet product, vegan diet, practicing time-restricted eating
- Severe chronic illnesses or other conditions that are incompatible with the planned intervention and examination program (e.g. type 1 diabetes, recent cardiovascular event, malabsorption, cancer in the last two years, etc.)
- Treatment with insulin, sulfonylureas, and GLP-1 receptor agonists, steroid use (oral, cutaneous, or parenteral), regular intake of melatonin, anticoagulation treatment that cannot be paused
- Extreme early and extreme late chronotypes
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Germany1 site, 1 recruiting
- Recruiting
German Institute of Human Nutrition Potsdam-Rehbruecke
Nuthetal, 14558
Olga Ramich, Prof. Dr., +49 33200 882749, olga.ramich@dife.de
Bettina Schuppelius, M.Sc., +49 33200 882692, bettina.schuppelius@dife.de
About this study
Official title: Precise Eating Time to Improve Glycemic Control and Cardiometabolic Health in Prediabetes and Diabetes: the GLYCOTIME Trial
The objective of this study is to investigate the impact of hypocaloric time-restricted eating (TRE) at different day times (early versus late TRE) on glucose metabolism and other cardiometabolic parameters in individuals with overweight and with normal, or impaired glucose metabolism (prediabetes and type 2 diabetes). In addition, the study aims to elucidate the molecular mechanisms underlying these effects.
Read the detailed description
This dietary intervention study will follow a crossover design. During the intervention phases, participants will restrict their dietary intake to a defined eating window of 8 hours - predominantly in the morning (early TRE) or predominantly in the afternoon (late TRE) - in conjunction with a moderate caloric restriction for five weeks. A 10-12-week washout phase will separate the intervention periods.
Overweight and obese individuals with healthy glucose metabolism, prediabetes, or non-insulin-treated type 2 diabetes will be recruited for the study.
- Conditions
- Prediabetes, Type 2 Diabetes, Obesity &Amp; Overweight
- Being tested
- Early Time-Restricted Eating, Late Time-Restricted Eating
- Keywords
- Time-restricted eating, Prediabetes, Type 2 Diabetes, Chrononutrition, Glucose metabolism, Overweight, Obesity, Continuous glucose monitoring, TRE, Prevention and treatment of type 2 diabetes
- Medical subject headings
- Prediabetic State, Diabetes Mellitus, Type 2, Obesity, Overweight, Intermittent Fasting
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Early Time-Restricted EatingBehavioural
Also called eTRE, early TRE
Participants will restrict their eating window (8 hours eating and 16 hours fasting per day) and caloric intake moderately.
During the early TRE intervention, participants will primarily consume their meals in the morning. The precise eating window will be defined based on the individual chronotype of the participants. Additionally, participants will be required to reduce their daily caloric consumption by 25%. They will replace one daily meal with a calorie-reduced product to facilitate caloric restriction.
Late Time-Restricted EatingBehavioural
Also called LateTRE, lTRE
Participants will restrict their eating window (8 hours eating and 16 hours fasting per day) and caloric intake moderately.
During the late TRE intervention, participants will primarily consume their meals in the evening. The precise eating window will be defined based on the individual chronotype of the participants. Additionally, participants will be required to reduce their daily caloric consumption by 25%. They will replace one daily meal with a calorie-reduced product to facilitate caloric restriction.
| Study group | Role | What they receive |
|---|---|---|
| Early Time-Restricted Eating | Experimental | Not described Receives: Behavioral: Early Time-Restricted Eating |
| Late Time-Restricted Eating | Experimental | Not described Receives: Behavioral: Late Time-Restricted Eating |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mean 24-hour glucose
Mean 24-hour glucose assessed by continuous glucose monitoring (CGM)
Measured: 5 weeks
Secondary outcomes (32)
Glycemic variability
Inter- and intraday indices of glycemic variability assessed by CGM
Measured: 5 weeks
Glucose levels
Fasting and postprandial glucose [mg/dL] in response to a mixed meal tolerance test
Measured: 5 weeks
Insulin levels
Fasting and postprandial insulin [mU/L] in response to a mixed meal tolerance test
Measured: 5 weeks
Glucagon levels
Fasting and postprandial glucagon [pmol/L] in response to a mixed meal tolerance test
Measured: 5 weeks
Insulin resistance
Insulin resistance, as assessed by HOMA-IR [AU]
Measured: 5 weeks
Insulin secretion
Insulin secretion, as assessed with the insulinogenic index [AU]
Measured: 5 weeks
Body weight
Body weight [kg], as measured by scale weight
Measured: 5 weeks
Body Mass Index (BMI)
BMI [kg/m2], calculated as weight/square height
Measured: 5 weeks
Waist and hip circumference
Waist and hip circumference [cm] measured by tape
Measured: 5 weeks
Body composition
Body fat mass and lean mass [kg], as measured by bioelectrical impendance analysis (BIA)
Measured: 5 weeks
Fasting cholesterol
Fasting total cholesterol, low-density lipoprotein and high-density lipoprotein cholesterol [mmol/L]
Measured: 5 weeks
Fasting triglycerides
Fasting triglycerides [mmol/L]
Measured: 5 weeks
Blood pressure
Systolic and diastolic blood pressure [mm Hg], as measured by manometer
Measured: 5 weeks
Resting energy expenditure
Resting energy expenditure [kcal/day], as assessed by indirect calorimetry
Measured: 5 weeks
Gene expresssion in adipose tissue
RNAseq analysis of subcutaneous adipose tissue samples
Measured: 5 weeks
Inflammatory markers in blood and adipose tissue
Levels of adipokines and inflammatory markers measured in blood samples and subcutaneous adipose tissue samples
Measured: 5 weeks
Subjective satiety and hunger sensation
Satiety and hunger scores assessed using Visual Analog Scales (VAS, with a scale of 1-100, where higher values correspond to stronger satiety/hunger)
Measured: 5 weeks
Concentration of satiety and hunger regulating hormones
Levels of ghrelin and peptide YY (PYY), as measured in blood samples in [pg/mL]
Measured: 5 weeks
Species and strain-level microbiome changes
Species and strain-level microbiome changes, as assessed by 16S rRNA gene sequencing of stool samples
Measured: 5 weeks
Levels of microbiome-derived metabolites
Levels of microbiome-derived metabolites measured in stool samples and blood plasma
Measured: 5 weeks
Sleep quality
Sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI score, which ranges from 0-21, where higher values correspond to worse sleep quality) and also monitored by an ActiGraph device
Measured: 5 weeks
Sleep and wake timing
Sleep onset and offset assessed by the Pittsburgh Sleep Quality Index (PSQI score, which ranges from 0-21, where higher values correspond to worse sleep quality) and in addition by using a sleep diary
Measured: 5 weeks
Internal circadian phase
Internal circadian phase as assessed using the BodyTime assay in peripheral mononuclear blood cells (PBMCs)
Measured: Screening visit (week 0)
Glucagon-like peptide-1 levels
Fasting and postprandial glucagon-like peptide-1 (GLP-1) in response to a mixed meal tolerance test [pM]
Measured: 5 weeks
Gastric inhibitory polypeptide
Fasting and postprandial gastric inhibitory polypeptide (GIP) in response to a mixed meal tolerance test [pg/mL]
Measured: 5 weeks
Gene expresssion in peripheral mononuclear blood cells (PBMCs)
RNAseq analysis of clock, metabolic and inflammatory gene expression peripheral mononuclear blood cells (PBMCs)
Measured: 5 weeks
Malondialdehyde
Plasma malondialdehyde [µmol/L]
Measured: 5 weeks
3-nitrotyrosine
Plasma 3-nitrotyrosine [pmol/mg]
Measured: 5 weeks
Protein carbonyls
Plasma protein carbonyls [nmol/mg]
Measured: 5 weeks
36-item Short Form Health Survey (SF-36) to measure health-related quality-of-life
Health-related quality-of-life, as assessed by the 36-Item Short Form Health Survey (SF-36, with scores ranging from 0 to 100, with a higher score defining a more favorable health state)
Measured: 5 weeks
Satisfaction with the intervention
Satisfaction with the intervention assessed by a 5-point Likert scale (with 5 representing "Very satisfied" and 1 representing "Very dissatisfied")
Measured: 5 weeks
Decision behavior
Impulsiveness assessed by decision making tasks on computer
Measured: 5 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Sep 2025
- Study start1 Oct 2025
- Primary completion31 Dec 2027 (estimated)
- Study completion28 Feb 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PrediabetesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- German Institute of Human Nutrition
- Sponsor type
- University, hospital or other
- Collaborators
- Technische Universität Dresden, University of Surrey, University of Geneva, Switzerland, Technische Universität München, Germany, German Center for Diabetes Research, University of Rovira i Virgili, Spain
- Responsible party
- Principal investigator, Olga Ramich (formerly Pivovarova), German Institute of Human Nutrition
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07171281
- Sponsor's protocol ID
- 85/2023
- Other IDs
- TEMP643937-BO-ff
- Acronym
- GLYCOTIME
- Status last verified
- Sep 2026
- First submitted
- 26 Aug 2025
- Last updated
- 29 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Precise Eating Time to Improve Glycemic Control and Cardiometabolic Health in Prediabetes and Diabetes: the GLYCOTIME Trial
- ClinicalTrials.gov ID
- NCT07171281
- Acronym / sponsor ID
- GLYCOTIME / 85/2023
- Conditions
- Prediabetes, Type 2 Diabetes, Obesity &Amp; Overweight
- Keywords
- Time-restricted eating, Prediabetes, Type 2 Diabetes, Chrononutrition, Glucose metabolism, Overweight, Obesity, Continuous glucose monitoring
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- German Institute of Human NutritionUniversity, hospital or other
- Collaborators
- Technische Universität Dresden, University of Surrey, University of Geneva, Switzerland, Technische Universität München, Germany, German Center for Diabetes Research, University of Rovira i Virgili, Spain
- Study start
- 1 Oct 2025 (actual)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 28 Feb 2028 (estimated)
- First posted
- 12 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The objective of this study is to investigate the impact of hypocaloric time-restricted eating (TRE) at different day times (early versus late TRE) on glucose metabolism and other cardiometabolic parameters in individuals with overweight and with normal, or impaired glucose metabolism (prediabetes and type 2 diabetes). In addition, the study aims to elucidate the molecular mechanisms underlying these effects.
Detailed description
This dietary intervention study will follow a crossover design. During the intervention phases, participants will restrict their dietary intake to a defined eating window of 8 hours - predominantly in the morning (early TRE) or predominantly in the afternoon (late TRE) - in conjunction with a moderate caloric restriction for five weeks. A 10-12-week washout phase will separate the intervention periods.
Overweight and obese individuals with healthy glucose metabolism, prediabetes, or non-insulin-treated type 2 diabetes will be recruited for the study.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Early Time-Restricted Eating | Experimental | Behavioral: Early Time-Restricted Eating |
| Late Time-Restricted Eating | Experimental | Behavioral: Late Time-Restricted Eating |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Overweight or obesity (BMI 25-40 kg/m²)
- Healthy glucose metabolism (fasting glucose <100 mg/dl and glucose after 2 hours OGTT <140 mg/dl)
- OR impaired glucose metabolism (fasting glucose 100-125 mg/dl and/or glucose after 2 hours OGTT 140-199 mg/dl and/or HbA1c 5.7-6.4%)
- OR type 2 diabetes (according to existing medical diagnosis or fasting glucose >126 mg/dl and/or glucose after 2 hours OGTT >200 mg/dl and/or HbA1c ≥6.5%)
- Daily eating window ≥12 hours
Key exclusion criteria (8 listed)
- Weight changes > 5% within past 3 months
- Shift work
- Traveling across more than one time zone within one month prior to the study
- Pregnancy and breastfeeding
- Eating disorders, food intolerance/allergy to ingredients in the diet product, vegan diet, practicing time-restricted eating
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Early Time-Restricted EatingAlso: eTRE, early TREParticipants will restrict their eating window (8 hours eating and 16 hours fasting per day) and caloric intake moderately. During the early TRE intervention, participants will primarily consume their meals in the morning. The precise eating window will be defined based on the individual chronotype of the participants. Additionally, participants will be required to reduce their daily caloric consumption by 25%. They will replace one daily meal with a calorie-reduced product to facilitate caloric restriction. | Behavioural | Early Time-Restricted Eating |
| Late Time-Restricted EatingAlso: LateTRE, lTREParticipants will restrict their eating window (8 hours eating and 16 hours fasting per day) and caloric intake moderately. During the late TRE intervention, participants will primarily consume their meals in the evening. The precise eating window will be defined based on the individual chronotype of the participants. Additionally, participants will be required to reduce their daily caloric consumption by 25%. They will replace one daily meal with a calorie-reduced product to facilitate caloric restriction. | Behavioural | Late Time-Restricted Eating |
Primary outcome
Mean 24-hour glucose
Time frame: 5 weeks
Mean 24-hour glucose assessed by continuous glucose monitoring (CGM)
32 secondary outcomes
Glycemic variability
Time frame: 5 weeks
Glucose levels
Time frame: 5 weeks
Insulin levels
Time frame: 5 weeks
Glucagon levels
Time frame: 5 weeks
Insulin resistance
Time frame: 5 weeks
Insulin secretion
Time frame: 5 weeks
Body weight
Time frame: 5 weeks
Body Mass Index (BMI)
Time frame: 5 weeks
Waist and hip circumference
Time frame: 5 weeks
Body composition
Time frame: 5 weeks
Fasting cholesterol
Time frame: 5 weeks
Fasting triglycerides
Time frame: 5 weeks
Blood pressure
Time frame: 5 weeks
Resting energy expenditure
Time frame: 5 weeks
Gene expresssion in adipose tissue
Time frame: 5 weeks
Inflammatory markers in blood and adipose tissue
Time frame: 5 weeks
Subjective satiety and hunger sensation
Time frame: 5 weeks
Concentration of satiety and hunger regulating hormones
Time frame: 5 weeks
Species and strain-level microbiome changes
Time frame: 5 weeks
Levels of microbiome-derived metabolites
Time frame: 5 weeks
Sleep quality
Time frame: 5 weeks
Sleep and wake timing
Time frame: 5 weeks
Internal circadian phase
Time frame: Screening visit (week 0)
Glucagon-like peptide-1 levels
Time frame: 5 weeks
Gastric inhibitory polypeptide
Time frame: 5 weeks
Gene expresssion in peripheral mononuclear blood cells (PBMCs)
Time frame: 5 weeks
Malondialdehyde
Time frame: 5 weeks
3-nitrotyrosine
Time frame: 5 weeks
Protein carbonyls
Time frame: 5 weeks
36-item Short Form Health Survey (SF-36) to measure health-related quality-of-life
Time frame: 5 weeks
Satisfaction with the intervention
Time frame: 5 weeks
Decision behavior
Time frame: 5 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Early Time-Restricted Eating and Late Time-Restricted Eating in people with Prediabetes and Type 2 Diabetes, run by German Institute of Human Nutrition at 1 site in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 29 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Olga Ramich, Prof. Dr. (+49 33200 882749, olga.ramich@dife.de), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mean 24-hour glucose (time frame: 5 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Sep 2026.