I don't have research for you, but I can share with you what works for my body. When I'm doing intense exercise for several hours without stopping (hiking to mountain peak, etc.) I run completely out of energy a few hours into it if I don't eat some carbs. My theory is that my body can't convert fat to fuel fast enough to keep up. But at that point I eat carbs, have energy again, and keep going. After the hike, I go back to doing my low carb with no problem whatsoever, as in no induction flu, etc.

That doesn't exactly answer your question, since you mentioned you have gotten past the "wall", which I never have been able to do without taking a rest. But in my opinion, if you're burning the carbs for fuel immediately, that makes all the difference.

But as they say, your mileage may vary.