A low-level ketogenic state likely represents an ancestral norm, with humans potentially being in ketosis 80-90% of the time at low levels.

“this is kind of the idea of a classic carnivore diet that it's totally reasonable and I believe consistent with normal human physiology and healthy and probably very beneficial long term to have some periods where you don't have carbohydrates in your diet”

“ketogenic human physiology as far as I can tell is probably the norm for humans rather than a carbohydrate based metabolism”