Vey Low-Energy Ketogenic Therapy in Adults With Type 1 Diabetes and Obesity on Intensive Insulin Therapy Using Advanded Hybrid Closed Loop System

Inclusion Criteria: Age ≥ 18 years Diagnosis of type 1 diabetes or autoimmune diabetes for ≥ 12 months BMI ≥ 30 kg/m² HbA1c \< 9% Knowledge and use of carbohydrate counting Use of an Advanced Hybrid Closed Loop (AHCL) system for ≥ 3 months and willingness to maintain it during the study At least 1 diabetology follow-up visit in the last 12 months (including telemedicine) Willingness to purchase meal replacements for the entire study duration Exclusion Criteria: Ketoacidosis, severe hypoglycemia with seizures/coma, or severe hyperglycemia requiring hospitalization in the last 6 months Febrile illness within the last 2 weeks Dietary restrictions or intolerances incompatible with study food supplies Celiac disease, gastroparesis, food allergies Intense physical exercise \>2 hours on \>3 days per week History or risk of eating disorder, or other psychiatric disorders Recreational drug use or excessive alcohol consumption Chronic kidney disease (eGFR \<60 ml/min) Gallstones Liver failure Heart failure (NYHA III-IV), unstable angina, cardiac arrhythmia, myocardial infarction, or stroke within the last 12 months Respiratory failure Severe or active infections Planned elective surgery Rare metabolic diseases (porphyria, CPT2 deficiency, mitochondrial fatty acid oxidation defect, pyruvate carboxylase defect) Pregnancy (current or actively trying to conceive) Breastfeeding Current glucocorticoid therapy (except stable low-dose, inhaled, or replacement for adrenal insufficiency) Other serious medical conditions that might interfere with participation or study completion in the investigator's judgment Participant judged unable or unwilling to complete the study