More on the overlap after the break.
Statistically speaking, boys are 15 times more likely to be diagnosed with Asperger's syndrome when compared to girls and conversely, girls are 10 times more likely to suffer from anorexia than boys. But for both conditions obsession — for anorexics perfectionism leads to obsession with weight and with Asperger's the obsession might be forms of transportation — is an integral element. Baron-Cohen explained that "The reason [Asperger's] is usually diagnosed less often in females may be because it takes a different form — anorexia may be just one of the forms." Members of the Eating Disorders Unit at Maudsley found that when anorexics are underweight they have difficulty interpreting other people's emotions, a trait found in people diagnosed on the autism spectrum.
Interestingly enough, the thinking patterns associated with both conditions — repetitive thoughts and behaviors, rigid routines and rituals, and perfectionism — may be present in the same region of the brain. Researchers in eating disorders hope to study this overlap in hope of finding more comprehensive treatments for anorexics. For more details, check out A Genetic Link Between Anorexia and Autism?