Precise Eating Time to Improve Glycemic Control and Cardiometabolic Health in Prediabetes and Diabetes
Precise Eating Time to Improve Glycemic Control and Cardiometabolic Health in Prediabetes and Diabetes: the GLYCOTIME Trial
German Institute of Human Nutrition
30 participants
Sep 19, 2025
INTERVENTIONAL
Conditions
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 diabetes). In addition, the study aims to elucidate the molecular mechanisms underlying these effects.
Eligibility
Inclusion Criteria5
- 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
Exclusion Criteria8
- 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
Interventions
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.
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.
Locations(1)
View Full Details on ClinicalTrials.gov
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NCT07171281