Scientists have discovered that the size of our brains may indicate the risk of developing an eating disorder, according to a study published in The Journal of the American Academy of Child and Adolescent Psychiatry.
Researchers from the School of Medicine at the University of Colorado say that a bigger brain may be a reason as to why people with anorexia are able to starve themselves, therefore presenting the possibility to predict onset of the disorder.
The researchers studied 19 adolescent females with anorexia nervosa, alongside 22 adolescent girls without the disorder.
Magnetic resonance imaging (MRI) was used to study the brain volumes of the participants.
Results of the scans revealed that the females with anorexia had larger left orbitofrontal, right insular, and bilateral temporal cortex gray matter, compared with the females who did not have anorexia.
The insula is an area of the brain that becomes active when we taste food, while the orbitofrontal cortex is a part of the brain that tells a person to stop eating.
The researchers conducted an additional comparison of this study with adults suffering from anorexia, alongside a healthy control group. Larger orbitofrontal cortex and insula volumes were also found in the adults with anorexia.
The fact that the orbitofrontal cortex is linked to signaling when a person feels satisfied after food suggests that a larger volume in this area of the brain could indicate a pattern across people with eating disorders, the researchers say.
They add that this pattern could encourage individuals with eating disorders to stop eating before they have had enough food, compared with healthy individuals.
"The negative correlation between taste pleasantness and orbitofrontal cortex volume in individuals with anorexia nervosa could contribute to food avoidance in this disorder," say the study authors.
Additionally, they note that the right insula is also responsible for our perception of body image. This enlarged area in anorexia sufferers may explain why they believe they are fat, even though they are underweight.
Guido Frank, assistant professor of psychiatry and neuroscience at the university, notes:
"While eating disorders are often triggered by the environment, there are most likely biological mechanisms that have to come together for an individual to develop an eating disorder such as anorexia nervosa."
According to the National Association of Anorexia Nervosa and Associated Disorders (ANAD), anorexia is the third most common illness among adolescents, with an estimated 0.5-3.7% of women likely to suffer from anorexia during their lifetime.
A 2012 study from Cincinnati Children's Hospital revealed that eating disorders may be predicted earlier by what girls eat as children.
Another study from researchers at the University of San Diego showed that brain responses to dopamine could predict "eating-induced anxiety" in anorexics.
Recent studies have also linked anorexia to other conditions. Research from the Autism Research Centre at Cambridge University in the UK, revealed that females with anorexia may have some of the traits observed in people with autism.