It wouldn't, because it's a natural function. Does eating food damage you? Because that's what spirits are to him, food. But eating someone allows for DIRECT access to his spirit, it's why it's so dangerous for him to eat a spirit that is stronger then him. Because it could just kill him, but not just like snap, killed. Would require a spiritual battle, which will be played out as a normal battle, although on the spiritual plane.
It doesn't Red, she just wants to tone down the character as much as possible because she's afraid of me having anything. :/