There are two kinds of carb loading before for a big ride, the stuff done to top up your glycogen reserves (best done the night before), and a reserve of energy in your stomach that is steadily digested as you exercise, to keep your reserves topped up and provide a buffer.
By waiting for digestion before going out, you're negating the benefit from it, as the glucose released by digestion will follow the same metabolic pathways as if you scooped some sugar into your gob - namely, any that doesn't get burned immediately or turned into glycogen will trigger a release of insulin that will convert it to fatty acids.*
Back when I used to do moderately large days on the bike, I'd add a dollop of marmalade to my porridge to give myself a burst of energy and allow me to overcome the "bogged down" sensation that comes with having heavy carbs sitting on the stomach.
As for fasted rides, they can be good efficiency training for your metabolism. If you do so, go for short hard efforts or medium steady efforts. And have food with you on the bike so that if you get into trouble you can get back out of it.
Hitting the wall a.k.a. "bonking" is not only one of the worst feelings in the world, it's dangerous.
* I'm not a nutrionist so I'm willing to accept that I might be wrong here.
