Illiterate Speech or Strange Wording?

What do you eat?

So this was a proverb/quote from Zaregoto: A series of be-headings. 

In short, for some reason the greatest minds that are living on this island to accompany a princess. They are being be-headed. (greatest minds being, best cook, physic, gadget master and so on).

In on of the episodes the chef master says this proverb

"If your liver is weak, eat liver.
If your stomach churns, eat stomach"

so it kinda hit me

'If your head/brain is broken, you eat...'

i'll leave it there for you xP