This is the most predictable story line each year: Extordinarily thin girl get's a stress fracture. Outsiders will say the injured girl was suffering from an obvious eating disorder and a few supporters say "you don't know her - she was always thin".
Sure there are injury prone runners even at the professional level but these recurring thin-girl injuries are entirely preventable.
I've been around anorexia and I know it's a hard topic to discuss but coaches, parents and friends should see these habits forming early on. In my experience, the most telling signs are obssesive-compulsive habits that don't always involve food. Eating is just one of the obsessive compulsive habits. If you see the signs please find someone that can speak to them.