Representative sample, Klump reported that 50 percent of the variability in individual differences in eating disorders can be attributed to genes. ("Are Eating Disorders Hereditary?") The author found that among Caucasians, eating disorders have a significant hereditary basis. People with certain rare genetic mutations are at significantly higher risk of developing an eating disorder. We know that eating disorders are hereditary, but a new study finally identifies two genes that significantly increase the risk of developing anorexia and bulimia (US News). A study by Stephanie Zerwas and Cynthia Bulik in 2013 reviewed several decades of genetic research (including family, twin, and adoption studies). Their studies reported that the heritability of anorexia nervosa and bulimia nervosa is between 33 and 84% and 28 and 83%, respectively. Interestingly, the rest of the variability we observed in behavior appears to be due to unique – not shared – environmental factors. A comparison of rates of eating disorders between identical and non-identical twins should help estimate the extent to which nature (shared genes) influences eating.