Believe it or not I was a very skinny child, which is the opposite of what you'd picture with a child who eats pet food. I was actually a very picky eater. Maybe I had pica. But the greater possibility is that I'm just a weirdo.
EDIT: looked up pica. I also used to eat salt by itself and I still drink pickle juice. went through a stage in my teens where I compulsively ate ice. how effing bizarre.