Hi first thing I got to say is no such thing as a stupid question cos if there is 8 am totally guilty of it all the time lol .
I don’t really know when quick acting insulin actually runs out and to be honest I don’t think it’s a hard nd fast rule , I do know it’s gone after a few hours but everyone is different. I’d even go as far to say the same person is different on different days , it’s one of diabetes anomalies.
I wouldn’t wait to eat until I think my insulin is away, I would just eat when I’m hungry and deal with the b/s. take b/ s after eating . If your bs is ok the way you do it now and you fancy more food then take a bit more if you go low eat sugar if you go high take insulin, complications won’t occur for small fluctuations in bs , it’s long term high bs that will cause probs, If I wanted my b/s to be “ flatlining constantly all I would be doing in my life is taking my bs ,
Years ago we took food for the amount of insulin we ate , it was extremely restrictive , now it’s a case of eat when your hungry . Sorry if I rabbit on a bit but I am welsh lol