I:C stands for Insulin-to-Carbohydrate ratio, which is a mathematical formula used by people with diabetes who take insulin to calculate the appropriate insulin dose based on the amount of carbohydrates they plan to eat. The ratio represents the number of grams of carbohydrates that one unit of insulin can cover. For example, if someone has an I:C ratio of 1:10, it means that one unit of insulin is needed for every 10 grams of carbohydrates consumed. This helps people with diabetes to more accurately calculate their insulin doses and manage their blood sugar levels. The I:C ratio is determined by a healthcare provider and can be adjusted based on individual insulin sensitivity and carbohydrate intake.