I don't think he is saying it works for everyone, nor is she saying it, and they're certainly not the only ones on this meat only diet thing.
I do know some people that can't consume other foods like normal people, i know people that can't eat red meat because they can't digest it, so it's in the realm of possibility that this bitch can't eat much else outside of meats and other things.
But yeah, the diet is fucking stupid and she'll be the downfall of Daddy P