Timing of Meals and Snacks With Diabetes

Learn when you should and shouldn't take insulin to correct for high blood sugar. It all depends on the timing of your meals and snacks.


Timing of meals and Snacks

A sliding scale is what you will use to determine how much insulin you need to give to correct an elevated blood sugar and/or for food. There are two parts: correction factor and insulin to carb ratio. In our example, the correction factor is half a unit to lower blood sugar 25 points, and insulin to carb ratio is half a unit will cover 10 grams of carbohydrate.

It’s all about timing. Because short-acting insulin lasts about two to three hours, it is best to spread out meals and snacks. If you’re taking insulin less than three hours apart, do not correct for high blood sugar. Only give insulin for the carbs you will eat. This is a false-high blood sugar and over correcting can result in stacking insulin and causing a low blood sugar. If you are taking insulin three hours or more apart, you can correct for high blood sugar and give insulin for the carbs you’ll eat.

There may be a special occasion where you eat a meal and one hour later, you are having dessert. In this case, it’s OK to give another insulin shot to cover the carbs you are going to eat in the dessert. Do not check blood sugar at dessert time, it will be high and should not be corrected.

If you have breakfast at 7, you would check your blood sugar, give insulin if needed to correct, and give insulin for food. There’s a classroom snack at 9:15, you will only give insulin for the carbs you are going to eat. If you check your blood sugar, it will look high, but that is not a true high.

School lunch is at 12:30; it has been three hours since you last ate, so you should check your blood sugar, give insulin to correct, if needed, and give insulin to cover the carbs in your lunch.

Topics Covered: Type 1 Diabetes, Type 2 Diabetes, Cystic Fibrosis-related Diabetes

Related Centers and Programs: Diabetes Center