Precise Eating Time to Improve Glycemic Control and Cardiometabolic Health in Prediabetes and Diabetes

Inclusion Criteria: * 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 Criteria: * 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