(hypo after pizza and Coke? I don’t think so!)
There’s an old thread (misc.health.diabetes sometime in the '90s) about the “pizza effect”, where you do the right bolus for a pizza (well, a slice) then end up with a hypo an hour later. It was one of those apocryphal stories that everyone responded to with “oh yes, I’ve experienced that” reactions, but I suspect there is something in fried bread that slows down the carb adsorption. Never proved it of course 
I started pumping with Fiasp about 3 months ago and my first pizza encounter since then was kind of like this. I pre-bolused pretty generously for the stuff, wanting to get a good head start on it, because, well, pizza. A while after eating, I drove my grandkids out to a playground a mile or two away, and when we got there and I got out of the car I suddenly realized I was losing my central vision. I checked BG and I was in the 40s. I think the real problem with pizza is the fat, which delays digestion. So what happened was the faster onset of Fiasp got there too far ahead and knocked me into a scary hypo before the pizza’s bread carbs could get going. I can see how you could get the same effect even from pre-Fiasp insulin by generously bolusing for the dread Za, only to be caught out by the fat delay effect.
Ya’ll are correct…its the fat. Before I had the 670G I would set up the full amount I would need, and extend it over 3 hours. It worked well. Everyone will be different…you may need 50% now the other 50% over 2-4 hours. With the 670G I take half at first, then 2 hours later do the other half. It seems to work.