I’ve never looked at them separately but I see where you’re coming from.
I’d say the bulk of my rides are fasted, usually, typically 5 rides a week fasted. My logic was: 1) better sugar control as mentioned 2) if I eat then ride I risk going hypo & not finishing the workout 3) if I leave the workout for later on in the day, this time of year, I can typically only do zone 2 rides rather than anything harder due to the heat generation.
Does the amount of fasted rides I’m doing, even if only short zone 2 rides, have a detrimental effect long term on fitness if done too often?