I think I'm other writers' hands this could be really good. The story is there and the metaphor is strong, but the script is garbage and awkward.
The filming style, while visceral and gross, is perfectly suited to the subject matter. Maybe having this be a horror movie pushed it too far out of the mainstream.
I can tell you from experience that this is an insanely accurate portrait of the realities of an eating disorder. I've seen just about every movie out there that deals with EDs and NONE have ever come as close as this to showing what it's really like. It very much is like having a second person inside you that you despise and that despises you right back. It's not glamorous, it's gross and sad and a hell of your own making.
I wish this was made by a more mainstream director etc because the message is important.