I have done 3 sprint triathlons since going keto. I make sure I stay well hydrated with added electrolytes. The only thing I have prior to the race is bullet proof coffee. I up my protein some the day before and afterwards, but other than that, no differences to my normal keto diet. I have cut significant amounts of time, feel invincible, and have virtually no “recovery” pains.
I should mention that I still have plenty of body fat to burn too. When I get to my goal weight, I imagine I will need more dietary fat.