Medtronic Treat to Range (TTR) Closed-Loop Control

Subjects will arrive in the morning and the TTR controller (Medtronic) will be initialized, and then they will give their usual premeal insulin bolus for breakfast. At lunch, they will either have a low glycemic index meal or a high glycemic index meal and the meal bolus will be omitted. The device will be turned off before dinner, they will have their usual insulin bolus for dinner, eat dinner, and then be discharged to home. On another admission, they will receive an insulin dose before lunch which will be 120% of their usual insulin bolus.