It's called, Self-Cannibalism. It's a disease.
A self - eater, i think.
The disorder is Pica.
Insecure
Ambitious.
Someone who is obsessed with themselves is commonly referred to as narcissistic or self-absorbed.
Clumsy
People from Brisbane do not tend to call themselves anything, except in relation to being a proud Queenslander. Sometimes people from Brisbane call themselves "Brisbanites".
Derealization and depersonalization sindrom.
You can call them George Costanza.
An animal that nothing else eats may be referred to as an apex predator. These predators are at the top of the food chain and have few or no natural predators themselves.
Anorexia, deppression, dieting, lonly, mentally ill
If you must label them, ask them how they would classify themselves.