Problems: Despite significant technological and treatment advances for people living with with type 1 diabetes (PWT1D), time in optimal glycemic targets remains difficult to achieve (between 4.0 and 10.0 mmol/L). On the other hand, there is increasing interest in low-carbohydrate diets in the general population (often for weight control), but also in people with diabetes, to help achieve glycemic control (associated with an increase in time in range (TIR).~Automated insulin delivery (AID) systems, including a continuous glucose monitor (CGM) coupled to an insulin pump with an integrated infusion algorithm, increase TIR by approximately 2 hours per day and reduce time in hypoglycemia by 30 minutes, compared to conventional treatments for type 1 diabetes. However, maintaining an optimal TIR remains a significant challenge for PWT1D, despite the increasing use of this technology.~AID systems in combination with a low-carbohydrate diet to optimize TIR have not been studied.~Objectives: To investigate whether low-carb diets improve glucose management and the feasibility of adopting low-carb diets among PWT1D using an AID.~Methods: This is a 12-month prospective, open-label, randomized, controlled study in adults living with type 1 diabetes, with the first 12 weeks as the main study phase and the rest as the extended study phase.~Admission period (2-4 weeks): Optimization of insulin doses, validation of carbohydrate calculations and maintenance of usual diet.~Main study period (3 months): Study assignment diet (low carbohydrate or usual).~Extensive study phase (9 months): Maintenance of assignment diet (if possible) with less frequent visits (observation period).~Hypothesis: The low-carb diet would increase the TIR% (primary outcome) by a mean of 8% (SD 8) compared with the usual diet. Power calculation: Using mean 8% (SD 8), that 38 adults (19 for each group) would provide 80% power at the 5% significance level to detect differences between the two interventions, after considering a 10% drop-out rate.~Full analysis set is defined as participants who have finished recruitment. Per-protocol set is defined as participants who have finished recruitment and have at least 70% of CGM data, at least 70% time in closed-loop mode and at least 4 full days of diet data during week 3-4. The efficiency analysis will be performed using the per-protocol set. The safety analysis will be performed using the full analysis set.
This is a randomized, controlled study in people living with type 1 diabetes using an automated insulin delivery (AID) system. Participants will be assigned to a control diet (45% carbohydrate) or a low carb diet (25% carbohydrate). The objective is to establish whether the low-carb diet improves time to glycemic targets at 3 months and whether the diet is realistically maintained at 1 year in patients using an AID-DIY system.