Speculations on the Link Between Sports and Anorexia


The Hypothesis

Running can cause anorexia nervosa in an otherwise healthy young woman. I do not mean to say that running is a risk factor for anorexia, that exercise may contribute to anorexia, sustain anorexia, aggravate anorexia or that the two are associated. I mean: Running can cause anorexia. 


“Why do females have to be so thin to be great?”

— amber sayer, from PR: A personal record of running from anorexia



In 2015, I finished up a book I was writing on obesity science. As a doctor working in the field, I grew ever more fascinated by the mechanisms that control human body weight. The book was largely my attempt to share a vast collection of research that goes largely unrecognized, showing without a doubt that obesity is not one's fault: internal body signals control our weight. I thought it would be easy to turn next to the problem of anorexia and write an explanatory book about the research describing where anorexia comes from. . . except that no such research exists. Well, maybe that's a bit harsh. There is a small amount of emerging science discussing the biological basis of anorexia, but the vast majority of what's been developed in the field focuses on the psychological aspects of the disease. As neurobiology has grown more influential to our understanding of psychological illness, a view of anorexia as a "brain based medical illness" is becoming more accepted. . .


What is Anorexia Athletica?

The eating disorder we call "anorexia" has some real nomenclature problems. Its formal name "Anorexia Nervosa" is inaccurate on both counts. "Nervosa" implies that this is a "nervous" condition which isn't really a term unless you are practicing psychiatry in Vienna one hundred years ago. "Anorexia" is Greek for "no hunger," which is also inaccurate, since most sufferers of the condition feel hungry all the time, they just do not respond to hunger by eating.

"Anorexia Athletica" is an older term that has never been in wide circulation, but it suits my thesis pretty well. . . 


Activity Based Anorexia


This story begins, as all good medical stories do, with mice. Two mice, to be specific, have volunteered to take place in a feeding experiment. The first mouse, Norma, is housed in a simple cage equipped in the usual fashion: water bottle, feeding dish and some light wood shavings for bedding. The second mouse, Anna, is housed in a cage with water, food dish and wood chips as well. But she is lucky and given access to a running wheel in her cage. This is a good thing for Anna, because mice love to run, and a healthy mouse will run about a 5k per night if given free access to either open space or a running wheel.


From a 2013 Study:


of adolescent, non-athlete boys had an active eating disorder


of adolescent, non-athlete girls had an eating disorder


of elite girl athletes, in sports for which lower weight yeilds a competitive advantage, had eating disorders


If eating disorders are so tied to athletics, and if the best athletes are the most prone, it seems likely that there is something in the training itself which brings on this disorder. Setting aside cultural factors within each sport and the cultural differences that boys and girls have with regard to appearance, I believe it is worthwhile to look for biological factors that respond to exercise that might serve as mediators of the disease. For the time being, I choose to call the missing link "Factor RA" for "Running Anorexia." Below are a host of considerations regarding this theoretical factor.


Defining Factor RA

One of the things that has given me a high level of enthusiasm for researching sports anorexia further, is the number of possible biochemical signals that I have found in the sports physiology literature that might be involved in driving the behavior of reduced eating. In order to sort the possibilities, it is necessary to create a proposed definition of Factor RA:

Factor RA is a biochemical signal, (or signals), created by the muscles, or another body organ, in response to exercise, which causes prolonged, cumulative alterations in appetite regulation, such that food is intake is diminished well below levels needed for adequate health. . .