Simon Baron-Cohen pioneered the idea that different brain types evolved to process information in gender specific ways. Here we expand this approach to looking at eating disorders as a byproduct of the extreme female brain. The incidence of eating disorders is higher among females, and recent findings show that hormones may play a role in eating disorders. We present new evidence from four studies that both an empathizing bias and hyper-mentalizing (as measures of the extreme female brain; EFB) are related to disordered eating and negative evaluation anxiety in women. We also advance the novel hypothesis that concerns about animal welfare (a unique expression of the EFB) may account for the relationship between vegetarianism and eating disorders.