When properly keto adapted, bonking is a thing of the past (that sounded kind of wrong...) because your body runs on ketonebodies made from fat of which we all have an almost unlimited ressource. Even a very lean athlete has in excess of 100.000 calories of body fat compared to a maximum of a few thousand from glycogen in the body.

So for endurance and long distance events it works great, not so much for super high intensity where the body prefers carbs. But you can train your body to be much, much better at burning fat. Even at high output, but it takes a while.

For more info read about guys like Phil Maffetone, Stu Mittleman and Tim Noakes. They all talk mostly bout running but the physiology on the cellular level is the same. BTW Maffetone trained Mark Allan when he won the Kona Ironman 6 times in a row, and he was NOT slow on the bike!