A Brief Overview of Shan Guisinger’s Adapt to Flee Famine Theory
There is not one concrete cause for the development of an eating disorder. Throughout time, scientists and researchers have theorized such illnesses through psychoanalytical, social, biological, and evolutionary lenses. One of my favorite theories was created by Shan Guisinger, and it is known as the Adapted to Flee Famine Theory. Guisinger suggested that the integration of conventional theories into the Darwinian framework may open doors with regard to new and effective treatment methods (1).
Darwin theorized that emotions initially evolved as an evolutionary response to motivate animals to behave adaptively in their present environments. I find this to be fascinating, as I am one to study biological and evolutionary processes, and I myself have hypothesized the cause of my own eating disorder. After all, our biology has a much tighter grasp on our desires, actions, and behaviors than we may believe! This is not to discredit other theories, or proclaim that one is “superior” to another. I do believe that there is not one cause for such illnesses as these, I just find this viewpoint to offer some clarity and insight into our history and biology!
The Adapted to Flee Famine Theory looks to migratory animals to better understand human evolution and the development of anorexia. In certain animals, migration is a biological response to perceived lack of food in the present environment. During a time in which said animals migrate, hunger cues cease so as to deter them from stopping to eat. This adaptation optimizes survival, seeing as stopping to eat wouldn’t serve them well when food is scarce! The premise of Guisinger’s theory suggests that certain individuals are at a genetic predisposition to developing anorexia. This is based on genetics, and how their ancestors evolved over time. She identifies three behaviors that characterize both the famine response and anorexia; ignoring food, hyperactivity, and denial of starvation (which includes body dysmorphia) (1).
The general hypothesis was that, when an individual loses at least fifteen percent of their average body weight (in today’s world, this is often the result of societal pressures and dieting), it is the equivalent of a famine. In those with the genetic predisposition to develop anorexia, hunger cues will shut off and the brain will enter “survival mode,” believing there is a lack of food and there is a need for migration. This ties in with the behavioral response to famine, and the phases in which starvation occurs. In the early stages, the desire for food will increase, and the metabolism will begin to slow as a precautionary mechanism to conserve energy. If the period of starvation is prolonged, and the fifteen percent threshold is crossed, the brain kicks into starvation mode and hunger cues vanish (2).
Some individuals report that the stress of overexercise and dieting activate reward mechanisms within the brain—characteristics common to the migration response. Further studies prove this theory, namely those conducted in the twentieth century involving rats and pigs. These study’s were done to best grasp how anorexia may fit in with Darwinian viewpoints and evolutionary ideas. A phenomenon known as “wasting pig syndrome” was studied in naturally lean breeds of pigs, showing that when additional weight is lost, it prompts the pigs to voluntarily restrict their diets and move incessantly. It was reported that six percent of pigs from lean breeds will develop this syndrome (2).
In the case of rats, those tested were reported to self-starve and exercise incessantly following restriction of feeding time, and presence of wheels within the environment. On average, rats will typically run one kilometer per day. When faced with starvation, the rats were observed to run an average of twenty kilometers per day. Through these studies, it was concluded that this hyperactivity and increase in restriction was in part attributable to increased serotonin turnover (3).
I just wanted to share some of what I found through my research with you all, as I do think it offers some explanation as to why eating disorders may occur, and it gives insight into the incredible intelligence of the body!
References:
Adapted to Famine, www.adaptedtofamine.com/.
Kersting, Karen. “An Evolutionary Explanation for Anorexia?” Monitor on Psychology, American Psychological Association, Apr. 2004, www.apa.org/monitor/apr04/anorexia.
Guisinger, Shan. “Adapted to Flee Famine: Adding an Evolutionary Perspective on Anorexia Nervosa.” Psychological Review, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/14599241/.