That is totally up to them. It is their decision. If they think it is good for you, they will prescribe it. Most likely they won't though. If you were once anorexic, it is possible it could happen again, so they most likely wouldn't do anything that could potentiall encourage that.
I had anorexia/bulimia for years when i first started seeing my psych, and he actually watched me go through my worst phase of disordered eating and extreme weight loss. i brought up my old ADD diagnosis (from when i was 13, six years ago), and complained that i just could not concentrate and i was worried about grades blah blah. truth was, i knew adderall had magical powers when it came to food cravings, AND I WAS SICK OF DEALING WITH THEM. when i got the script, id been "semi-recovered" for a while. i also had a history of drug abuse, but neither of these stopped him.
P.S. any anorexic who comes in contact with this godsend is pretty much screwed, im thin as a rail now and i STILL never think about food, i actually have to force myself. its a dream sometimes, but other times i really feel like a collapsed umbrella.