How does CCG keep ghouls alive for so long in their prisons when they can only eat humans? The same goes for half ghouls in CCG. What do they eat?
Quinx squad keeps their RC level low enough they can eat regular human food. (Post time skip Urie is seen eating at some fancy dinner with I believe Matsuri Washuu if I didn't get the name wrong.) Additionally in very early chapters of :re Sasaki cooks food for Mutsuki. During Kaneki's flashback of his imprisonment after the events of V14 it's shown that some sort of slop is pushed through his door which he doesn't eat. Otherwise perhaps quinx are given RC repressants as well which could help with hunger. Kaneki notes in chapter 99 that he was using RC suppressants in his time with the CCG (albeit noting it had an effect on his hair color).
Exact chapter citations forthcoming when I have time.