Yep…I was a Diet Pepsi fiend but had to switch to caffeine free Diet Pepsi. Didn’t matter what time of day I drank it (tended to be afternoons anyway)…it always spiked me and I had to bolus for the equivalent of about 15g carbs.
I have done this. It dosen’t seem to matter when I drink caffeine I get a spike. My only problem is like others the spike is inconsistent. I usually give just a little up front and make up for the rest later. I should mention it spikes me but not a huge amount. Usullay just 20-30 mg/dl without a pre-bolus. You are right about the morning hormones though. The spike seems to be greater in the morning but what is interesting is if I don’t have coffee my basal rate keeps my BG’s stable and where they need to be.
I think my coffee is built into my bolus LOL. I drink it all day with a tad of heavy cream. I’ll have to NOT drink it for a few hours some time and see if I go low.