Eating Disorders & the Brain
In eating disorder recovery, there is a common misconception that weight restoration is the key to complete remission. Many treatment facilities often make this the focal point of their treatment protocols, utilizing the number on the scale to indicate how “healthy” a client may be. Rather than simple weight restoration, true recovery involves the rewiring of the neural pathways through repeated behavior change, in order to create new habits and establish healthy coping mechanisms. The neural rewiring process is the brain’s way of healing itself, which is quite often disregarded or overlooked. Neural rewiring is vital, as this is what rewrites those entrenched behaviors that have become deeply rooted throughout the progression of the disorder. Without neural rewiring, behaviors and beliefs remain unchanged, and relapse is imminent.
In my experience in recovery programs, neural rewiring was never mentioned. I had only learned of this process when I embarked on recovery in the latter half of my teens, and began to do a great deal of digging on my own. This is not to demonize or impart any negativity on the systems in place, I simply want to mention that it is imperative that neural rewiring is discussed, as it is vital to complete recovery.
The brain, with regard to eating disorder development and recovery, can be complex to comprehend. It helps to break it down into it’s three key regions—the cerebrum, the cerebellum, and the brainstem, to best understand their functions and how they play into habit formation, muscle memory, and behavior patterns. The cerebrum, which is the largest and frontmost part of the brain, is responsible for voluntary movement and temperature regulation within the body. Towards the back of the brain lies the cerebellum, which is the smallest region of the brain, and is responsible for muscle movements, posture, and balance. The brainstem, which lies inferior to the cerebellum, is comprised of three parts; the midbrain, pons, and medulla (“survival brain”). This “survival brain” is a key player in the development of an eating disorder from an evolutionary perspective, and explains why these deep-seeded behaviors become so entrenched.
Grey matter is another component of the brain, vital in movement control, the formation of thoughts and emotions, and the ability to retain memories. This tissue, comprised of neuronal cell bodies, presents around all parts of the brain and within the center of the spinal cord (1). The grey matter that surrounds the cerebrum is what is known as the cortex, where the cerebral cortex is located. This is the rational part of the brain, responsible for personality, intelligence, and the processing of sensory information (among many other important functions).
Studies indicate that individuals suffering from anorexia nervosa display altered brain structure, characterized by significantly less grey matter than that of a healthy brain (2). A study conducted by the University of Southern California in 2022, including roughly two-thousand brain scans on an international scale, concluded that individuals presenting with a diagnosis of anorexia nervosa displayed significant shrinkage in this grey matter, both in thickness and volume of the cortical complexes (2). Individuals in recovery, however, displayed restoration of this grey matter, indicating that through nutritional rehabilitation (and neural rewiring), the brain can heal itself and reverse the damage done as a result of the condition (2).
The medulla is the portion of the brain that meets the spinal cord, and is responsible for regulating heart rhythms, breathing, blood flow, and regulation of oxygen and carbon dioxide levels in the body. This part of the brain contrasts the cerebral cortex as it is instinctual, rather than rational. Upon sensing a perceived “threat,” the medulla will automatically kick into survival mode without communication with and thus overriding the cerebral cortex.
The medulla reacts to immediately presented data, without emotional or rational context. This means that it automatically enters what is referred to as “the scarcity mindset” when resources are perceived to be sparse. When this happens, the survival brain kicks into high gear, triggering the “fight, flight, or freeze” response. It is reacting to the present energy deficit, whether the cause be true famine or intentional under eating. Without this survival mechanism, our ancestors would not have survived periods of hardship and famine; hence why under-fueling and over-exercising commonly kickstart the migration response (another theory for another day).
The amygdala and basal ganglia, both part of the limbic system and located within the temporal lobes of the brain, are responsible for habit formation, emotional regulation, and pattern recognition. Once habits are formed and behaviors become entrenched, the prefrontal cortex (associated with decision making) is no longer consulted, as behaviors become automatic (3, 4).
Neuroplasticity is the brain’s ability to modify and adapt it’s structure and function in response to lived experiences. Essentially, the brain can form new connections that rewrite behavior sequences, present both in the development of an eating disorder, and throughout recovery. In eating disorder recovery, this entails the restoration of balance between the rational and emotional components of the brain, characteristic of the amygdala (3, 4).
Neural rewiring is just as crucial to recovery as nutritional rehabilitation. The two go hand in hand, as nutritional rehabilitation is the key to repairing the physical damage done to muscles and organs (including the brain!), while neural rewiring is the act of challenging and changing of those seemingly hard-wired behaviors. Without neural rewiring, the brain cannot completely heal and recover, but true recovery is possible and attainable to all who seek it.
References:
Guy-Evans, O. (2021, May 19). Grey matter in the brain. Grey Matter in the Brain - Simply Psychology.
Retrieved September 4, 2022, from https://www.simplypsychology.org/what-is-grey-matter-in-the-
brain.html
Sheehan, S. T. (2022, June 14). Groundbreaking study shows substantial differences in brain structure in people with anorexia: Keck School of Medicine of USC. Keck School of Medicine of USC | Leaders in medical education, research and patient care. Retrieved September 4, 2022, from https://keck.usc.edu/groundbreaking-study-shows-substantial-differences-in-brain-structure-in-people-
with-anorexia/
Kippert, A. (2022, September 4). How trauma rewires the brain. DomesticShelters.org. Retrieved September 4, 2022, from https://www.domesticshelters.org/articles/health/how-trauma-rewires-the-
Schönfeld, L.-M., & Wotecki, L. Beyond emotions: Oscillations of the amygdala and their implications for electrical neuromodulation. Frontiers. Retrieved September 4, 2022, from https://www.frontiersin.org/articles/10.3389/fins.2019.00366/full