Blood glucose levels change after meals and after physical activity or stress, therefore insulin must be taken multiple times a day to match the changes in blood glucose levels. This method is called Multiple Dose Insulin injections (MDI). In MDI we use one long acting insulin (e.g. Glargine) at night, and a short acting insulin 3-4 times before meals during the day. There is a formula to calculate the insulin dosage based on blood glucose levels, carbohydrate (CHO) count in the diet, activity level, and other factors. Training of this is called Diabetes Self-Management Education (DSME) provided by a certified Diabetes Educator which empowers both patients and their families with knowledge on how to manage insulin dosage.
There is no cure for diabetes however, with good control, one can live a normal life. The following quote from Prof. George Alberti, past President of International Diabetes Federation, summarizes the fundamentals behind the management of T1D:
We can therefore divide the management of T1D in three categories- all of which are necessary for good control of diabetes and prevent complications.