Originally Posted by FrenchFit

I'm intermittent fasting, no food during the day, month 4, age 60. The glycogen reserves are stunning, I'll often take a energy bar with me on a long ride and bring it back unopened. No bonking, no cramping. However, the very high output, red zone, capacity is simply gone. I'm speculating that carbo loading and fueling is akin to blood doping, there is so much of a glucose/insulin reaction in the blood you are always in an over-reved mode, and you have to keep supplementing it because once it depletes you go to bonktown. Hammer Syndrome would be a good name for it. But I'd agree with the argument: super-human efforts are not going to happen on metered glycogen reserves, the red-line gets pegged much lower.