YOU SAID:
Eat food that is supposed to be eaten
INTO JAPANESE
食べられるはずの食べ物を食べる
BACK INTO ENGLISH
Eat food you can eat
INTO JAPANESE
食べられる食べ物を食べる
BACK INTO ENGLISH
Eat eatable food
INTO JAPANESE
食べられる食べ物を食べる
BACK INTO ENGLISH
Eat eatable food
That didn't even make that much sense in English.