Findings suggest that anorexia nervosa may be related to a biological adaptation that thousands of years ago helped migrating populations find food.

Researchers believe that nomadic people possessed a natural instinct that prompted them to move on when food supply was low. In an article for American Psychological Association, psychologist Shan Guisinger, PhD explains that when starvation sets in, most people demonstrate an intense hunger and desperation for food. However, when those with a genetic tendency toward anorexia experience starvation, they tend to feel calm, unfazed, even energized.  Members of nomadic groups who were better able to withstand hunger may have had a higher chance of survival.  It’s possible that some even became leaders, finding plentiful food sources and then guiding others to these food sources as well.  So “the core symptoms of the disease {anorexia] make adaptive sense.”

I absolutely see the validity of this theory when I reflect on what I see in practice with patients with anorexia.  These individuals often have remarkable energy and an overwhelming drive to move (surprising given their emaciated, malnourished bodies)… In fact, driven, extreme exercise is often a core struggle for our patients with anorexia.  They often report an overwhelming drive to walk, run, move… any kind of physical outlet. Further, there is almost always an extreme focus on food in anorexia nervosa.  Whether it’s thinking about recipes, planning meals, baking, cooking shows or looking at photos of food on the internet, the focus on food is profound under the influence of anorexia.  

If you think about these symptoms (heightened food focus and compulsion to exercise) from an evolutionary perspective it makes perfect sense: under the influence of starvation, our ancient ancestors fared best if they had a biologically-based drive to ambulate (or move) – and fast – to locations with more plentiful food supply.  And having food on their minds 24/7 allowed them to maintain a laser focus on finding food… which ultimately means survival.  It’s even worth considering the advantage of a decrease in libido and loss of menstrual period which commonly occur when someone is malnourished and underweight.  Way back when, it was best if you were not distracted by sexual urges or having babies – both distractions and means for depleting energy and resources…  not good when you’re starved and trying to relocate to where you might establish more consistent and adequate nourishment.

So what do we do given this natural biological drive under the influence of anorexia?  The most important thing is restoring weight back to a normal range.  Once the body and mind know that they are getting consistent and adequate nutrition again, the food focus and movement compulsion tend to dissipate.  We see this time and again in treatment.  As the body returns to health, so too does the mind and these biologically-based drives no longer serve the same purpose.  After all, we’re not living in an environment of food scarcity. As Guisinger so aptly stated, “Evolution is not very elegant sometimes, and adaptations persist where they are not needed. In this case, the adaptation turns off hunger in modern women who diet.”