Actually I've always had problems eating when my mother wouldn't cook for me. For example when I was studying abroad, or when she's away for a few days. I've discussed that at length and realized I don't think I deserve any food, and that's it's a waste... but if my mother gives it to me, then it's ok to eat. And then I will eat as much as possible, because you never know what could happen and when I would next be allowed to eat. (My mother never deprived me of food, just screwed up thinking on my part)

But lately I've been aware that a lot of the things she does is out of guilt for the abuse I've been through. So if she feeds me out of guilt, that's kind of the same as me not deserving any food... but I can't not eat in front of her, so all that's left is purging after I've eaten...