Medical Complications of Anorexia

Most people with eating disorders feel that they are superhuman and impervious to the various medical complications that inevitably arise during the course of the illness. Books and articles present lengthy lists of the ways the body deteriorates from an eating disorder. I find the medical details numbing and completely disconnected from the reality of the disorder itself. I end up drifting when I try to absorb the information and I really want to remember it! If I cannot maintain focus, imagine how much a patient--deeply ambivalent about recovery--will actually remember. It makes much more sense to organize the information into a series of necessary steps the body takes in order to survive chronic starvation and vomiting rather than a laundry list of impersonal problems.

Let's start in this post with the effects of starvation. In the short run, eating less means the body uses more energy than it takes in. The body initially burns fat--the energy storage unit--to make up the extra needed calories. This line of reasoning is familiar as the natural result of a diet. Once the fat stores are depleted--a few months at best--the body adapts to survive the apparent famine in three interconnected ways: the use of protein as the new energy source, harboring limited resources for the most basic functions and a gradual slowing of metabolism.

Once the body begins to break down protein as an alternate energy source, survival becomes a zero sum game. Fat storage exists largely as a reserve to protect against lean times. Any use of protein as energy means using up this valuable and necessary resource. The body initially burns up skeletal muscle protein leading to atrophy and decreased strength. In time, however, any protein will do including cardiac muscle which leads to a weakening heart--one of the myriad ways eating disorders kill. Essentially, the body slowly eats away at itself to create as much energy as possible to survive, no matter the cost. However, the body was not created to survive through self-cannabalism. There are many deleterious effects, and one of the most severe is that protein metabolism leads to different waste products that need to be cleaned out of the bloodstream. The kidneys are damaged by the prolonged exposure to protein waste products, and even recovery will not always fully repair renal function. If this were the only adaptation to starvation, anorexia would kill people much more quickly so let's shift to what happens to metabolism.

During this prolonged famine, the body has to decide how to use its limited resources. For people with eating disorders, this concept is not evident because food feels like an unnecessary indulgence rather than a critical resource. Sometimes an analogy can emphasize why these circumstances are so dire and circumvent the denial of a patient. Consider a community experiencing severe drought. At first, people may decide to stop watering their lawns, a minor inconvenience. As the drought worsens, desperation sets in and the residents may agree to flush toilets less frequently or may limit each household to a maximum quantity of water per day. Finally, plumbing may be shut off completely so that individuals need to go to pick up their daily ration of water at a local well. Similarly, the body takes increasingly drastic steps for survival. For example, two common initial sacrifices the body makes during starvation are decreased peripheral circulation and trouble focusing--two functions not needed during a famine. The next step might be prolonged fatigue and dizziness, from not using energy to pump blood up to the head. More severe famine necessitates drastic changes: slowed heart rate and very limited mental function. The body may gradually eliminate all needs outside of the heart and lungs: the basic needs for minimal survival. Although the body will do anything to continue to live, the sacrifices are enormous.

The third way someone survives famine is a gradual, steady decrease in metabolism. The body, almost miraculously, adapts to become an extremely efficient machine. Each and every calorie of energy extracted from food is used as wisely and judiciously as possible. The gastrointestinal system slows down until it is almost paralyzed. In part this is atrophy from lack of use but also is to ensure extraction of every bit of energy from the limited food intake. Then the body slows down all of its functions in order to maximize the use of the energy taken in and minimize self-cannabilizing. There are countless examples. Liver function slows down leading to excess waste products in the bloodstream. Immunity is weakened and leads to increased susceptibility to infection. Heart rate slows down to levels commensurate with limited survival. The menstrual cycle stops because it isn't possible to be pregnant with limited resources and the menses itself wastes valuable resources.  Maintenance of healthy bones ceases. These adaptations severely limit what people with anorexia can do and often lead to irreversible damage.

This intuitive approach to the medical problems of anorexia is much harder for patients to dismiss. Humans have learned to adapt to famine in order to survive. Anorexia only exploits these genetic adaptations. It is unclear to me how effectively medical knowledge leads someone towards recovery, but I find that patients are more likely to process and remember the information presented in this way. The next post will describe the medical effects of binging, purging, and laxative and diuretic abuse.