Anorexia might be linked to brain size
New research indicates that the risk of developing anorexia may be tied to the size of your brain. A bigger brain may be the reason that anorexics can starve themselves. Females with anorexia had larger left orbitofrontal, right insular and bilateral temporal cortex gray matter compared to non-anorexic females.
http://www.medicalnewstoday.com/articles/265196.php