A common feature in many eating disorders is distorted body image, and an overemphasis on the importance of weight and shape to one’s value as a person. Our cultural emphasis on dieting, thin models, and digitally altered images certainly plays a role. However, if the body image distortions were only caused by media factors, nearly everyone would suffer from an eating disorder. Nor do cultural factors explain the documented existence of eating disorders in cultures and time periods without a cultural emphasis on thinness. New research is showing that individuals with eating disorders have differences in the way they perceive their own shape and size that appears to be strongly influenced by biology.

Everyone has a body image. Researchers define body image as the way we picture and perceive our bodies in our minds, and this perception is shaped by broader cultural factors, our own individual experiences, and by how our brains perceive the size of our bodies and how they move through space. Only in more recent years have scientists begun to tease apart how these neurological factors can affect the development of body image in eating disorders.

It appears that several regions of the brain are involved in this body image distortion. In a neuroimaging study of women recovered from binge/purge anorexia, researchers found that higher serotonin receptor activity in the left parietal cortex was associated with lower drive for thinness (Bailer et al., 2004). A separate study also found abnormal activation of the parietal cortex when individuals with anorexia were asked to look at pictures of themselves (Wagner et al., 2003). The parietal cortex helps to create a map of the body using the sensory information it processes, and researchers have hypothesized that problems with creating this body map may at least in part underlie body image distortions in eating disorders (Titova et al., 2013). This hypothesis is supported by research that showed patients currently ill with anorexia had problems retrieving accurate information about their body shape that caused them to overestimate their current body size (Mohr et al., 2010).

These distortions also appear to involve the brain’s fear circuitry. Scientists in Germany asked three adolescents currently hospitalized for anorexia to view pictures of their own body that had been digitally altered to appear larger and thus simulate the teens’ actual body image. When the teens with anorexia looked at the  digitally altered images of their bodies, the activity in their fear circuits increased significantly when compared to the activity when these teens viewed digitally altered images of healthy teen bodies (Seeger et al., 2002).

Although more research has been done looking at the neurobiology of body image in people with anorexia, it appears that many of the same processes may occur in people with bulimia. When researchers asked 13 women with anorexia, 16 women with bulimia, and 27 healthy controls to view pictures of their own bodies in a bikini, the activity in the parietal cortex was similar in both groups of eating disordered women (Vocks et al., 2010).

Studies have found that body image dissatisfaction plays a role in binge eating disorder (Grilo & Masheb, 2005), as does body image distortion (Mussell et al., 1996); however, no neurobiological studies have been completed to determine the nature of these body image issues.

In adolescent girls without eating disorders, scientists have found that the extent to which a teen girl believes that her body should conform to the cultural ideal of extreme thinness (known as thin ideal internalization) appears to be somewhat heritable (Suisman et al., 2012). The authors of the study believe that perfectionism may play a role in this, as highly perfectionistic people may likely express the need or desire to have a “perfect” body. Indeed, independent studies have found that, in individuals without eating disorders, people who have higher levels of perfectionism also experience higher levels of body dissatisfaction (Wade & Tiggemann, 2013). It’s also not yet clear how thin ideal internalization interacts with the neurobiological differences discussed above to alter a person’s risk for an eating disorder.

References

Bailer, U. F., Price, J. C., Meltzer, C. C., Mathis, C. A., Frank, G. K., Weissfeld, L., ... & Kaye, W. H. (2004). Altered 5-HT2A receptor binding after recovery from bulimia-type anorexia nervosa: relationships to harm avoidance and drive for thinness. Neuropsychopharmacology, 29(6), 1143-1155. doi:10.1038/sj.npp.1300430

Grilo, C. M., & Masheb, R. M. (2005). Correlates of body image dissatisfaction in treatment‐seeking men and women with binge eating disorder. International Journal of Eating Disorders, 38(2), 162-166. DOI: 10.1002/eat.20162

Mohr, H. M., Zimmermann, J., Röder, C., Lenz, C., Overbeck, G., & Grabhorn, R. (2010). Separating two components of body image in anorexia nervosa using fMRI. Psychological Medicine, 40(9), 1519. DOI: 10.1017/S0033291709991826

Mussell, M. P., Peterson, C. B., Weller, C. L., Crosby, R. D., Zwaan, M., & Mitchell, J. E. (1996). Differences in body image and depression among obese women with and without binge eating disorder. Obesity Research, 4(5), 431-439. DOI: 10.1002/j.1550-8528.1996.tb00251.x

Seeger, G., Braus, D. F., Ruf, M., Goldberger, U., & Schmidt, M. H. (2002). Body image distortion reveals amygdala activation in patients with anorexia nervosa–a functional magnetic resonance imaging study. Neuroscience Letters, 326(1), 25-28. DOI: 10.1016/S0304-3940(02)00312-9

Suisman, J. L., O’Connor, S. M., Sperry, S., Thompson, J. K., Keel, P. K., Burt, S. A., ... & Klump, K. L. (2012). Genetic and environmental influences on thin‐ideal internalization. International Journal of Eating Disorders, 45(8), 942-948. DOI: 10.1002/eat.22056

Titova, O. E., Hjorth, O. C., Schiöth, H. B., & Brooks, S. J. (2013). Anorexia nervosa is linked to reduced brain structure in reward and somatosensory regions: a meta-analysis of VBM studies. BMC psychiatry, 13(1), 110. doi:10.1186/1471- 244X-13-110

Vocks, S., Busch, M., Grönemeyer, D., Schulte, D., Herpertz, S., & Suchan, B. (2010). Neural correlates of viewing photographs of one’s own body and another woman’s body in anorexia and bulimia nervosa: an fMRI study. Journal of psychiatry & neuroscience: JPN, 35(3), 163. doi: 10.1503/jpn.090048

Wade, T. D., & Tiggemann, M. (2013). The role of perfectionism in body dissatisfaction. J Eat Disord, 1(2). doi:10.1186/2050-2974-1-2

Wagner, A., Ruf, M., Braus, D. F., & Schmidt, M. H. (2003). Neuronal activity changes and body image distortion in anorexia nervosa. Neuroreport, 14(17), 2193-2197.