What causes eating disorders?

What is the biopsychosocial model of eating disorders?

The biopsychosocial model of eating disorders considers the interaction of the biological, psychological, and social factors that can contribute to the development of eating disorders like anorexia nervosa, bulimia nervosa, binge eating disorder, orthorexia nervosa, and more. (1)

Biological risk factors

Several biological factors can increase the risk of developing eating disorders.

Family history of eating disorders

Typically, a person is more likely to develop an eating disorder if there is a family history of eating disorders, issues with food restriction, and/or excessive dieting. (2) This correlation can be attributed to both genetics and observed behaviors.

Studies show varied rates of heritability, with estimates ranging between 28% and 88% of those with a family history of eating disorders developing a disorder themselves.³

Negative energy balance

Expending more energy than you take in causes what’s known as a negative energy balance. Studies have indicated that a negative energy balance—which can have a variety of causes, including dieting, growth spurts, illness, and intense athletic training—particularly during puberty, can lead to the development of eating disorders. (2) This is one of the reasons why dieting is dangerous and always inadvisable, especially for children and teenagers.

Type 1 diabetes

Research indicates that 25% of women diagnosed with type 1 diabetes will subsequently develop an eating disorder. (5) Diabulimia is an extremely dangerous eating disorder that can occur in people with type 1 diabetes which involves restricting or going without insulin with the goal of losing weight. Insulin restriction can occur alongside other disordered behaviors such as over-exercising, restricting food, and purging. (5)

Other biological factors

Additional biological and genetic factors that may also play a role in the development of eating disorders include:

• A personal history of dieting and other weight-manipulation methods
• Parental substance use disorder
• High parental demands
• Having a close family member with a mental health condition

Psychological risk factors

In addition to biological risk factors, eating disorders tend to develop in those who have certain psychological issues or a mental illness.

Perfectionism

One of the strongest psychological risk factors for an eating disorder is perfectionism, particularly a form of perfectionism known as self-oriented perfectionism, which is characterized by setting unrealistically high expectations for yourself.¹

People with perfectionism may engage in certain behaviors motivated by their perfectionist beliefs, such as excessive checking (including body checking), correcting others, list-making, and excessive organizing.⁶ They may also avoid doing certain things, such as eating certain foods, out of fear that they won’t meet their own standards.⁶

Personal history of anxiety disorder

Research indicates that a personal history of an anxiety disorder (such as generalized anxiety disorders, panic attacks, social phobia, and obsessive-compulsive disorder) is more likely to subsequently develop an eating disorder. 

For example, studies have shown as much as two-thirds of those with anorexia nervosa demonstrated signs of an anxiety disorder before the onset of their eating disorder.²

Body image dissatisfaction

Body image is defined as your thoughts, perceptions, and attitudes toward your physical appearance. A negative body image (body image dissatisfaction) involves feelings of shame, self-consciousness, and a feeling that one’s body is flawed compared to others.⁷

Research shows that body image concerns start at a young age, and over one-half of teenage girls and almost a third of teenage boys use unhealthy weight manipulation behaviors in response to those concerns.⁷

People with eating disorders are more likely to report high levels of body dissatisfaction and internalization of an ideal body image.²

Behavioral inflexibility

A particular trait common in those with anorexia nervosa, behavioral inflexibility refers to an impaired ability to switch flexibility between different actions, tasks, and rules, as well as a strong belief that there is only one correct way to do things.⁸

Other psychological factors

Some other psychological influences on the development of eating disorders may include:^1,2

• Novelty-seeking traits i.e., a tendency to pursue new experiences that trigger intense emotions, such as thrill-seeking and risk-taking
• History of physical, emotional, or sexual abuse
• Neuroticism i.e., a tendency for emotional instability and negative mood states such as depression, anger, anxiety, fear, and loneliness
• Conduct disorder, which is a behavioral disorder characterized by a contempt for social norms and antisocial behaviors

Social risk factors

Society in general, your friends and family, and social media can also influence the development of an eating disorder.

Weight stigma

In a virulently fatphobic culture, the message is everywhere: "thinner is better”. Weight stigma is perpetuated by the media (including social media), doctors and medical professionals, family members, and even individuals’ attitudes toward themselves. This can lead to discrimination and stereotyping against people in higher weight bodies, which typically increases body dissatisfaction.²

Acculturation

There is an increasing body of evidence that suggests there is a strong association between culture change/acculturation and eating disorder psychopathology.⁹

Those who are undergoing rapid Westernization are at a particularly increased risk of developing an eating disorder due to the complex interaction between body image, acculturation, and stress. For example, within just three years of the introduction of Western television to Fiji, 74% of women experienced dissatisfaction with their body size, 69% dieted to lose weight, and 29% were at risk of clinical eating disorders.²

Teasing or bullying

Being teased or bullied—particularly about weight—is a risk factor for the development of many eating disorders. Bullying can lead to low self-esteem and poor body image and has been shown to directly contribute to the development of eating disorders. Research estimates that as many as 65% of people with eating disorders claim bullying contributed to their condition.¹⁰

Historical/intergenerational trauma

Intergenerational trauma i.e., huge cumulative group trauma across generations, such as Holocaust survivors and persecution of Indigenous groups, has been linked to the development of eating disorders. More research is needed to assess the effect of oppression on eating disorders.²

Other social risk factors

Other sociocultural factors that may contribute to the development of an eating disorder include but are not limited to:^1,2,11

• Limited social networks, with loneliness, isolation, and little social support, are linked to eating disorder development and maintenance
• Appearance, ideal internalization, striving for the socially-defined “ideal body,” and obsession with thinness. 
• Present and/or past food insecurity or inconsistent access to food 
• Separation from a parent(s)
• Significant life transitions, such as moving, changing jobs, unemployment, the death of a loved one, and the end of a relationship
• Having a job or taking part in activities where there is a focus on appearances, such as athletes, dancers, actors, or models.

Causes of eating disorders—final thoughts

When you or your loved one develops an eating disorder, there is no one to blame. Eating disorders develop due to the interaction of numerous biological, psychological, and social factors. 

This is not a complete list of all the risk factors that contribute to the development of eating disorders, as they are complex conditions with various causes and presentations. Rather, this list features the factors that are common to the majority of eating disorders in order to provide some insight into these complex mental health disorders.

While it may be impossible to discern exactly which combination of factors produces an individual’s eating disorder, identifying and working through triggers and traumas that play a role in perpetuating eating disorder behaviors can be an important aspect of treatment. And while this may seem daunting and difficult, help is available, and it is never too late to reach out for support.