Applying Very Low Calorie Ketogenic Diet to the Treatment of Obesity in People With Type 1 Diabetes on Intensive Insulin Therapy Using Automated Insulin Delivery System
Overweight and obesity are frequent in adults with type 1 diabetes (T1D), with prevalence exceeding 50% in recent studies. Excess weight in T1D is associated with higher cardiometabolic risk and therapeutic challenges, while effective and safe weight management strategies are still limited. This single-center, single-arm feasibility study will evaluate the efficacy and safety of a Very Low-Energy Ketogenic Therapy (VLEKT; 600-800 kcal/day) in adults with T1D and obesity treated with Advanced Hybrid Closed Loop (AHCL) insulin delivery systems. Participants will follow a structured 4-week program with commercial very-low-carbohydrate, high-protein meal replacements, under close medical supervision. The primary endpoint is change in body weight at 4 weeks. Secondary outcomes include body composition, muscle strength, glucose metrics, insulin requirements, biochemical parameters, and patient-reported outcomes. Safety will be assessed through hypoglycemia incidence, ketone monitoring, and occurrence of diabetic ketoacidosis (DKA). The study will enroll 14 participants. It is expected that VLEKT will achieve \ 5% weight loss within one month while maintaining glycemic safety under AHCL technology.
• 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