how soon to eat after insulin injection

[kelvin]

My son uses the 70/30 insulin pen twice a day - before eating breakfast and before his evening meal. He usually injects and then eats straight away - is this OK? I was under the impression that it is best to wait a while. Any thoughts?

[JDRF-Team-sgg]

The answer is "it depends". I am not being vague, but how soon he should eat depends on what his glucose level is when he tests. If his glucose is high, then he should wait to allow it to lower to the normal range so he doesn't risk a very high spike while waiting for these insulins to begin to work. Neither of these insulins are types that start to act immediately, and the ideal is to time the meal so that he is doing his primary digestion at the same time that the insulin is peaking. This sort of timing may be different for different people, depending on how quickly their bodies absorb the insulin and how quickly they digest their foods.

If, on the other hand, his glucose level tends to be low or on the lower side of normal when he tests before a meal, it makes sense to eat immediately so the body can digest and absorb some of the carbs and raise the low sugar levels before the insulin begins its peak activity.

You and your son can find out how well his routine is working for him by testing both before and about an hour after he eats to see whether his glujcose levels are remaining fairly constant or whether they are rising tremendously or dropping tremendously after he eats. For his best health, it is good to try to avoid spikes both high and low.