Insulin Timing for Diabetics: Before or After Meals?

A diabetic usually injects insulin prior to a meal because the substance takes between 10 and 45 minutes to start working. Injecting it after a meal means blood sugar spikes before the insulin has time to counteract it. However, there are some circumstances in which it makes sense to inject insulin after a meal.

Diabetic Children Who Are Picky Eaters

• Insulin dosages at mealtimes are partially based on the number of grams of carbohydrates that are going to be consumed. If a diabetic child refuses to eat all of her dinner but has already received an insulin dose that was based on her consuming her entire meal, a dangerous hypoglycemic (low blood sugar) reaction can occur. Consequently, some parents prefer to administer an injection immediately after a meal so they can be sure the dosage is correct.

Low Blood Sugar

• If blood sugar levels are low before mealtime, a diabetic may choose to inject right after eating a small meal to give levels time to return to normal.

Carb-Free Meal

• Foods with no carbohydrates, such as cheeses and meats, don't require insulin to balance them, so if a diabetic injects after eating a meal that contained no carbohydrates, it may be because she was simply snacking and it is time for their normal scheduled injection.

Forgetfulness

• On occasion, even the most careful diabetic will forget an injection and have to administer it after eating.

Warning

• Injecting insulin after eating without a specific medical reason is a dangerous long-term practice. In order to avoid serious complications, diabetics should strive to keep their blood sugar level as even as possible; the constant post-meal spikes that will occur if they inject insulin after (or while) eating can have lethal consequences.