Treating Patients With Renal Impairment and Altered Glucose MetAbolism With TherapeutIc Carbohydrate Restriction and Sglt2-Inhibiton - a Pilot Study

Inclusion Criteria: * Chronic Kidney Disease Stage KDIGO 3a-4 (eGFR eGFR 25-59 mg/min/1.73m²) * Prediabetes or Diabetes according to the Guideline of the American Diabetes Association (HbA1c \>5,7 percent, or fasting glucose values \> 100 mg/dL, or glucose levels \> 140 mg/dL at 2h during an oral glucose tolerance test) * Being overweight (Body Mass Index \> 25.0 kg/m²) * Being able to independently: * \- Perform measurements of blood glucose and ketone levels * \- Use a continous glucose monitor * \- Contact the study team Exclusion Criteria: * Patients who are allergic to SGLT-2-Inhibitors * Patients with autoimmune diabetes (Typ 1 or LADA) * Patients with pancreoprivic diabetes * Patients with a history of ketoacidosis or lactate acidosis * Patients with severe hypoglycemic episodes in the 6 moths prior to inclusion * Patients with bariatric surgery (in the past or planed) * Patients with nephritic range proteinuria (\>3,5g of Albumin/day) * Patients with active malignant diseases * Pregnant or breastfeeding patients