There is more than one instance of pain inflicted upon a dog. One dog, in particular, is killed during a particularly harrowing story arc shortly before the protagonist is raped. It is a violent and sad scene and mentioned by the protagonist at the time and after, as she also deals with the dog's body.
No characters have an eating disorder specifically, but there are instances of starvation and disordered eating in mentions of restriction, self imposed and otherwise forced.