If your gut is absorbing it, those carbs will be used to fuel the work or elevate blood sugar so that cognitive drive remains high, or both. Then subsequently re-pack muscle with glycogen post-workout if blood sugar remains elevated, as is ideal.
Yes but minimally. I think maybe 2 studies have investigated it. Only one of the top of my head. Rowlands and colleagues I believe. I think it’s a pretty safe bet that optimal ratio is somewhere between 0.8:1 and 1.3:1 gluc:fruc.
My intuition is that 15 yrs down the road recommendations will be something to the effect of:
If you’re doing 90g/hr, target 1.3:1
If you’re doing 100g/hr, target 1.2:1
If you’re doing 110g/hr, target 1.1:1
If you’re doing 120g/hr, target 1:1
If you’re doing 130g/hr target 1:1
If you’re doing 140g/hr target 0.95:1
If you’re doing 150g/hr target .9:1
Totally made that up on the spot, based purely on intuition. Also did no math to verify my logic.
If you have an FTP of 300+, you will never not benefit from more carbs, if gut-tolerance allows, for rides over 2 hrs. MAYBE for racing, maximizing carb intake isn’t so important and staying in the 90-120 range at 2-hr ride duration is reasonable, but for 2-hr training rides, there is very little reason not to encourage max carb availability during training to maximize recovery, adaptation, and future carb-burning and absorption ability in the future.