HI, I've been meaning to post a discussion about this for awhile... when I was first put on insulin (pork/beef) in 1984 the doctor told be to wait 20 minutes minimum up to an 1 hour before eating (If I recall correctly). Mid to late 1980's I began using Humulin R (short acting), the doctor still told me to wait at least 20 minutes up to 1 hr before I began to eat food. I would usually wait 30 minutes.
Fast forward to 2002, with the invention of "rapid acting insulin" my doctors began telling me I could eat right away, "this insulin (Novolog) begins immediately!" So for years I would eat and dial up my insulin at the same time. Why would I wait? this is silly, so 1984!
I do a lot of good for my diabetes, I TAG most of my meals, I use a pump where I can deliver a Dual Wave Bolus, I wear a CgM that has a blood sugar trend arrow on it, I eat a semi-low carb diet and even exercise a little each day. All of this is thrown out the window if I do not time my insulin and food properly up front, honestly. I notice (for me) Novolog does not start working "right now".. it just doesn't, no matter how much they want to tell me this. My blood sugars are SO much better when I wait 20-30 minutes.
Do you time your insulin? Did your doctor tell you that you could bolus right as you ate? ... no wait time? Do you have decent sugars when you eat and bolus at the same time?... or do you find if you wait a few minutes your sugars are much more spot on? What did your doctor tell you on this topic? Please include what insulin you are injecting...