A lot of it is anorexia by another name. There is a subspecies that involves compulsive exercise. Doing lots of athletics without proper nourishment is a good recipe for low performance and injury.
> A lot of it is anorexia by another name.
Literally my first thought after reading this training log excerpt:
> 10/4/2012: I’m really trying to be conscious right now about losing some worthless snack weight… Need to be more diligent, take action, get fucking after it, and restore the body and the mind!
"worthless snack weight" sounds very similar to epithets that anorexic people often use.
That particular issue is known as RED-S: https://en.wikipedia.org/wiki/Relative_energy_deficiency_in_...
But over-training can happen even with sufficient nutrition (even if it is less likely, as nutrition is a major part of post-exercise recovery).