I like think the reason why kanmusus eats a lot (ref. Akagi, Kaga, and, in this case, Yamato) is because their "armored suit" drains energy from their bodies, like some sort of mana, and then they need to replenish their energy in base of their power level.
So, if kanmusus becomes normal girls, by scrapping, retirement or something else, welp, they become normal girls, and thus, they stomachs becomes human.
I like think the reason why kanmusus eats a lot (ref. Akagi, Kaga, and, in this case, Yamato) is because their "armored suit" drains energy from their bodies, like some sort of mana, and then they need to replenish their energy in base of their power level.
So, if kanmusus becomes normal girls, by scrapping, retirement or something else, welp, they become normal girls, and thus, they stomachs becomes human.
Akagi is the only exception. Will eat entire civilizations regardless.