There are definitely much more than two defining characteristics, but heres what I’ve narrowed down
Perfectionists- anorexia is oftentimes a defense mechanism for those who really need a sense of control in their lives but can’t find it so they turn to controlling their diet because that is something they can control.
Endurance..? I’m not sure if this is the best word choice because it seems positive but it gets the idea across. Their obsession with control will oftentimes go very far. They will ignore one of the most important survival instincts- to eat, to satisfy their bigger craving of control among other things.
Here are some other traits you could choose: impulsive, controlling, obsessive