A well-timed pre-bolus can do a great job with many meals! We find that there is no way we can stop meal spikes unless we do a good job pre-bolusing.
First, we established how long it takes us for our insulin to become active: for us, 40-45 minutes after injection, Novolog (or Humalog) becomes strongly active, and strongly inflects the BG track downwards. We call this “turning the corner.”
If we are already within range when pre-bolusing (we like to be between 90 and 100), we time the pre-bolus exactly according to the activation time, i.e. for us we pre-bolus 40-45 minutes prior to the meal. If we are a bit high, we add enough time to come down by that much. If we are lower, we typically eat very few carbs to bring us back up - maybe start with a lunch appetizer that has 3-4 carbs, just enough to give us a boost (and, of course, take off the appetizer from the carb count).
Then we wait until we turn the corner: once the corner is turned, we eat RIGHT AWAY!
Below is my boy’s lunch curve today:
Pre-bolus at 11:05, lunch (59 carbs) at 11:45. The red line is at 70, the yellow line is at 120.
It is not always as smooth
Notes and comments:
Time it takes for insulin to activate varies widely per person: YDMV!
The glycemic index of the meal makes a difference to how early you would want to pre-bolus. A meal with a low glycemic index needs a shorter pre-bolus interval. Again, YDMV!
Time of day makes a difference to the efficiency of pre-bolusing. Again, YDMV!
Because of the significant individual variations, this is a process that needs personal experimentation.
End of wiki ---------- comments start here