About Eating Disorders

What is an eating disorder?

An eating disorder is a type of mental health challenge that involves extreme food or weight preoccupation and eating behaviours that are harmful to physical and mental health. There are strict criteria to define clinically diagnosable eating disorders, and many eating disorders go undiagnosed. We encourage you to get support for disordered eating thoughts and behaviours, whether or not you have a clinical diagnosis.

Definitions help health professionals understand how each condition develops and progresses, and how to treat people with similar symptoms.

Eating disorder diagnostic criteria from the DSM V (Diagnostic and Statistical Manual of Mental Disorders) cover the following diagnoses, among others:

  • Binge eating disorder
  • Bulimia nervosa
  • Anorexia nervosa
  • Avoidant/restrictive food intake disorder
  • Rumination disorder
  • Pica
  • Other specified feeding and eating disorder (OSFED) – includes atypical anorexia nervosa and night eating syndrome
  • Unspecified feeding or eating disorder (UFED)

For more information on signs, symptoms, and diagnoses, please visit the National Eating Disorder Information Centre’s website.

Please note that while the DSM is used for diagnosing, these illnesses and experiences can occur along a continuum and you do not require a diagnosis to access our services. If you are living with disordered eating or body image distress and do not have a DSM diagnosis, you can still join our groups.

What causes an eating disorder?

Eating disorders (EDs) are complex illnesses resulting from interacting biological, psychological and socio-environmental factors.

Biology, genetics, and the environment

Eating disorders have been shown to have a degree of heritability (Bulik, 2004) as their incidence clusters more frequently within specific families. The degree of heritability is difficult to estimate, with research indicating anywhere between 0 and 70% for anorexia, and 0 and 83% for bulimia (Fairburn et al., 1999). There is a great deal of research into specific genes and biological mechanisms associated with EDs, but also evidence about how familial environments may contribute to EDs (e.g.. modeling of eating behavior, high levels of perfectionism, low levels of emotional expression). While biological factors may be implicated in the etiology of EDs, it is vital to appreciate these illnesses from a biopsychosocial perspective.


Western society places a high value on thinness, and associates the attainment of the thin ideal with good health, success, and intelligence. There is increasing pressure to diet and lose weight, especially for young women and increasingly for men as well, and many of the behaviours associated with EDs are socially lauded. Social pressures to lose weight are becoming increasingly prevalent, especially as obesity and weight loss become areas of heightened concern in North America. In support groups for EDs, it may become important to challenge some of the false beliefs associated with thinness and weight loss, and explore the realities of natural variations in weight and shape.


Certain family factors have been shown to place an individual at a higher risk of developing an eating disorder or disordered eating. These factors include: a family history of mental illness, maladaptive family attitudes to food or weight, aversive mealtime experiences, communication problems, children who are given too much responsibility to parent themselves, neglect or abuse and high parental standards, among others.


Research in the community has examined how peer attitudes about food and weight are transmitted within social groups. Eisenberg and Neumark-Sztainer (2010) observed that girls who reported more dieting in their peer group had a greater likelihood of engaging in chronic dieting and being dissatisfied with their bodies. In addition to peer influences, membership in certain subgroups such as athletics, dance, and modeling may provide increasing pressure to maintain a certain weight and therefore place an individual at greater risk of becoming preoccupied with food and weight.

Individual factors

A variety of psychological factors have been implicated in the etiology of EDs, including low self-esteem, depression, decreased feelings of effectiveness, perfectionism, rigidity, overvaluation of appearance, difficulties with distress tolerance, emotional dysregulation and excessive concern with the opinion of others (Jacobs et al., 2009, Vohs, 2001). It is important to consider how individual psychological traits may be affected by the individual’s sociocultural environment.

Precipitating and perpetuating factors

College and university students exhibit particularly high rates of EDs for several reasons. Some of these factors include stressors associated with the transition to adulthood, first experiences with independent living situations, post-adolescent weight gain, fears of social evaluation and academic pressures.

Personality traits such as perfectionism, neuroticism, negative emotionality, and harm avoidance have been found to be associated with the development and maintenance of anorexia and bulimia.

Concurrent diagnoses

Concurrent diagnoses are common in individuals with eating disorders. Anxiety and mood disorders are more prevalent in this group, and there are also higher rates of obsessive-compulsive disorder (Zaider et al., 2000). Higher rates of social phobia, substance use, and personality disorders have also been observed in individuals hospitalized for eating disorders (Grilo et al., 1996). It is common for concurrent mental health concerns to emerge as a result of the ED as well. For example, depression is very common in women who experience starvation (Wilsdon & Wade, 2006).

Function of an eating disorder

Eating disorders often provide a sense of safety, regularity and control for individuals who experience their lives as chaotic. For this reason they are often seen in individuals with a low sense of effectiveness or self-competence. Eating disorders may provide a sense of achievement for those with low self-esteem and help to regulate emotions, among various other functions. Eating disorders are often an individual’s best attempt to cope.