Fourth, the identification of significant negative correlations between anorexia nervosa and BMI-related and anthropometric measures could potentially serve as an important first step toward gaining a better understanding of the shared biology underlying extremes of weight dysregulation (i.e., obesity vs. anorexia nervosa). This is of critical importance as adequate explanations for how individuals with anorexia nervosa reach, sustain, and revert to exceedingly low BMIs have been elusive. Clinically, one of the most perplexing features of anorexia nervosa, is how patients’ bodies seem to revert rapidly to a “low set point” after renourishment, which may represent the biological inverse of the reversion to high set points commonly seen in the unsuccessful treatment of obesity (31, 32). As noted by Bulik-Sullivan et al. (23) and Hinney et al. (33), these observations extend our understanding that the same genetic factors that influence normal variation in BMI, body shape, and body composition may also influence extreme dysregulation of these weight-related features in anorexia nervosa. This pattern of observations complements prior strong evidence for the involvement of neural mechanisms in obesity (34). Finally, positive correlations
