By Catherine A. Sanderson, Amherst College
People with eating disorders clearly do not pay attention to internal cues of hunger. Instead, they are often refusing to eat even when they are hungry—even starving, in the case of anorexia nervosa—and then bingeing on huge amounts of food when they are clearly not hungry. So, what causes these disorders, in which the motivation to eat for biological reasons—hunger—is clearly not working right? Read on more to find out.

Anorexia and Bulimia Nervosa
Many people eat as a way to regulate their moods and, in particular, to feel better. When we feel sad, we are likely to drown our sorrows in a pint of ice cream or a bag of chips. So, in this case, our eating is a form of self-medication. It’s not motivated by true hunger.
However, when we speak of battling an eating disorders, it is a serious psychological disorder. In this case, one’s eating behavior is not at all motivated purely biological factors. People with anorexia nervosa show a drastic reduction in their weight, at least 25% of what they should weigh, based on their height. They have an intense fear of becoming obese and tend to feel fat even when they are dangerously thin.
This disorder, which is much more common in girls and women than in men and boys, can lead to serious and long-lasting health problems, including osteoporosis, bone fractures, and heart damage. It can also be fatal.
Another relatively common eating disorder is bulimia nervosa. People with bulimia engage in repeated episodes of binge eating—consuming large amounts of food in a short time—coupled with attempts to purge these calories, such as by vomiting, use of laxatives, or excessive exercise. This repeated binging and purging leads to a variety of medical problems, including cardiac arrhythmia, digestive disorders, and damage to the teeth, throat, and stomach.
What Affects Our Eating Habits?

When it comes to understanding the biological causes of eating disorders, they often could include levels of particular neurotransmitters, hypothalamus disorders, or genetic or hormonal disorders. For example, eating disorders are much more likely to appear in both members of a twin pair if they are identical than if they are fraternal, suggesting genes are involved in some way.
But environmental factors clearly also play a role. Families of people with eating disorders often show particular patterns, including relatively high rates of alcoholism and depression. This finding suggests that disordered eating may be an attempt to regulate mood.
Women with anorexia in particular often come from families that are competitive, high-achieving, and protective. This pressure may lead them to set high standards and focus intently on how they appear to others.
This article comes directly from content in the video series Introduction to Psychology. Watch it now, on Wondrium.
Broader Socio-cultural Factors
Finally, broader socio-cultural factors, such as the strong emphasis on thinness in women seen in most Western cultures, are also thought to contribute. In one fascinating study, researchers compared preferences for different body sizes in people living in three distinct parts of Nicaragua. One group was living in an urban area, with regular access to most forms of media. The second group resided in a village with only television access. The third group lived in a remote area with little access to electricity and hence almost no access to media.
Participants in each of the three areas were shown images of women’s bodies that varied on degree of thinness and asked to rate their attractiveness.
Eating Disorders and the Role Of Media
Contrary to popular perception, people with virtually no exposure to media rated the thinner bodies as the least attractive. Those living in the area with the most media exposure rated the thinner bodies as most attractive. These same patterns were seen in a higher desire to lose weight and higher rates of dieting by women in areas with the most media.
Thus, these findings clearly suggest that the presence of a thin ideal in the media may influence both men’s and women’s beliefs about what is considered attractive, and in turn, could increase the risk of disordered eating.
Common Questions about Understanding Motivation and Eating Disorders
People with anorexia nervosa show a drastic reduction in their weight, at least 25% of what they should weigh, based on their height. They have an intense fear of becoming obese and tend to feel fat even when they are dangerously thin.
People with bulimia engage in repeated episodes of binge eating—consuming large amounts of food in a short time—coupled with attempts to purge these calories, such as by vomiting, use of laxatives, or excessive exercise.
Families of people with eating disorders often show particular patterns, including relatively high rates of alcoholism and depression. This finding suggests that disordered eating may be an attempt to regulate mood.