The Different Causes of Eating Disorders

When a person gets sick, it's natural to want to understand why. With eating disorders, which are associated with many myths and negative stereotypes, the question of causation can be incredibly confusing.

The culture at large commonly blames eating disorders on oversimplified explanations, such as the media's promotion of unrealistically slender models or bad parenting. Even some health professionals buy into these overly simplistic explanations.

This article explores some of the risk factors that may increase the likelihood that a person might develop an eating disorder, including the impact of both environmental and genetic variables. It also discusses the potential causes of specific eating disorders, such as binge eating disorder, anorexia nervosa, bulimia nervosa, and purging disorder.

Risk Factors for Eating Disorders

Many factors have been, or are being, studied as possible contributors to the development of eating disorders. Across all types of eating disorders, it is likely that mental health and body image-related factors play a significant role in causing eating disorders.

Mental Health

Mental health risk factors can include anxiety, depression, low self-esteem, and trauma such as childhood sexual abuse. Social stressors, such as peer pressure and bullying, may also be involved.

Body Image

Risk factors related to eating behaviors and body image may also be tied to the development of eating disorders. These could include:

• Teasing and critical comments about weight
• Body dissatisfaction
• Having a fixation with a thin body

Family Dynamics

Family dysfunction has long been cited as a cause of eating disorders. However, families don't cause eating disorders in a simple, straightforward manner.

While growing up in a dysfunctional home could increase the risk for many psychological problems, including eating disorders, it does not condemn a child to an eating disorder or any other psychological disorder.

Some research suggests that family functioning characterized by high levels of rigidity may be associated with a higher risk of disordered eating behavior.

Other Factors

Early childhood feeding, eating, or gastrointestinal problems can also contribute to the development of eating disorders.

Risk Factors for Specific Eating Disorders

Risk factor research focuses on identifying traits or experiences that precede the development of a specific eating disorder (not just the overall category of eating disorders). For a risk factor to be shown as a causal factor, the risk factor must come before the development of the eating disorder.

The risk factor(s) must also be capable of being manipulated to prevent the occurrence of the disorder. For example, smoking is a causal risk factor for lung cancer; it comes before the development of the disease, and not smoking reduces one’s risk of developing lung cancer.

To date, there is limited research that has successfully demonstrated causality; however, a 2016 study found the following causal risk factors for specific eating disorders:

Anorexia Nervosa

People with anorexia nervosa restrict their food intake, have an intense fear of weight gain, and have a distorted perception of their weight and health. A low body mass index (BMI)—essentially, underweight—has been identified as a risk factor. However, anorexia nervosa can still happen in people with a BMI in the normal range.

Bulimia Nervosa

Bulimia nervosa, characterized by repeated episodes of binge eating and purging, has several identified risk factors. These include:

• Believing that thinness is equivalent to attractiveness (thin-ideal internalization)
• Having a negative body image (body dissatisfaction)
• Perceiving external pressure to be thin
• Dieting frequently
• Taking weight loss supplements

Binge Eating Disorder

Binge eating disorder is similar to bulimia nervosa but without the purging aspect. This eating disorder was added to the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5) in 2013.

One study noted that in girls, the following were associated with binge eating in adulthood:

• Body dissatisfaction in adolescence
• Depressive symptoms
• Low self-esteem
  

Purging Disorder

Purging disorder is similar to bulimia nervosa, but in this case, the behavior is limited to purging without binge eating. The only causal risk factor identified by the 2016 research is dieting. Other research has suggested that risk factors for purging disorder are similar to those for bulimia nervosa and binge eating.

Genetic Factors

Coming from a family with a history of eating disorders can increase a person's risk of developing an eating disorder. A portion of this increased risk could be due to the modeling of eating disorder-linked behaviors within a family (e.g., observing a family member dieting).

However, twin study research, which can isolate the role of genetics, suggests that approximately 40% to 60% of the risk for anorexia nervosa, bulimia nervosa, and binge eating disorder arises from genetic influence.

Latest Research

The largest and most rigorous genetic investigation of eating disorders ever conducted, the Anorexia Nervosa Genetics Initiative (ANGI), is currently underway in the United States, Sweden, Australia, the United Kingdom, and Denmark. This research could provide more information about the genetic profile that contributes to eating disorders.

These findings do not imply that there is a single eating disorder gene or even that genes cause eating disorders. Some individuals may inherit traits such as anxiety, fear, perfectionism, or moodiness that have been associated with the development of an eating disorder. These aspects of temperament have also been linked to several other disorders.

Prevalence in Families

Some people with eating disorders are able to identify several other family members who also have eating disorders. There are certain families in which the risk of eating disorders is much higher than in the general population, but such families are relatively rare.

Even a high-risk family history indicating an increased genetic risk does not mean a person is destined to develop an eating disorder. Conversely, not everyone with an eating disorder can identify another family member with one.

Most eating disorder cases are sporadic, with no family history. Given the smaller size of today’s families, there is often not enough data to determine whether a specific individual has a genetic tendency.

Environmental Factors

Much of the earlier research on eating disorders examined environmental risk factors. As a result, they are frequently blamed for causing eating disorders. Environmental factors include events and influences in an individual’s life, such as:

• Diet culture
• Social media
• Trauma
• Weight teasing

Influences such as gender, ethnicity, or certain athletic settings can strengthen or lessen other environmental factors.

The tripartite model is one model for understanding some of the socio-cultural risk factors for eating disorders. It proposes that exposure to media, peer, and parental messages all contribute to whether a person idealizes thinness and engages in social comparison. Idealization and social comparison may lead to poor body image and various forms of disordered eating.

Protective Environmental Factors

Some environmental factors could help protect people from developing eating disorders. These could include:

• Family meals
• Eating breakfast
• Emotional regulation skills
• Mindfulness techniques

Techniques that help groups and individuals question and challenge unrealistic beauty ideals (including the glorification of thinness and the stigmatization of overweight people) are also helpful and protective. People are starting to practice body positivity and neutrality.

Social and environmental changes, such as improving the status and power of women, reducing the objectification of both men and women, and increasing respect for people of all sizes and shapes, will benefit everyone, not just those at risk for eating disorders.

Gene and Environment Interplay

Neither genes (nature) nor environment (nurture) cause eating disorders independently. Eating disorders are likely the result of a complicated interplay of these factors.

Even when a precipitating factor (such as a traumatic event) can be identified, there is almost always a combination of other contributing factors that play a role. The precipitating factor is most likely the trigger that knocked over the first domino and tripped a cascade of events.

Genetic susceptibility may influence their response to specific stressors. For example:

• A person genetically susceptible to an eating disorder may be more sensitive to weight-related teasing and have a heightened reaction to it (for instance, initiating a diet that snowballs into a disorder).
• A person who is genetically vulnerable may continue dieting much longer than peers who diet and then stop.
• A person with the temperament that commonly underlies anorexia nervosa (anxious and perfectionistic) may seek out the types of social environments that contribute to the onset of dieting.

Epigenetics

The emerging field of epigenetics, the study of whether, how, and when genes are expressed, offers further insight. Epigenetics explains that certain environmental factors determine the expression of genes or even turn specific genes on or off in the next generation.

In terms of eating disorders, there is evidence that the longer a person has anorexia nervosa, the greater the chance they will have alterations in how their genes are expressed. It appears that malnourishment could turn on or off certain genes, which influence the course of the disorder. However, epigenetic studies of eating disorders are in their infancy.

Final Thoughts

Just as environmental factors can increase a person's susceptibility to an eating disorder, the converse is also true: Changing the environment can facilitate prevention and recovery. For example, growing up with warm, nurturing parents could mitigate genes predisposing someone to anxiety. However, chance and luck also play a role, and individuals vary in their genetic risk.

Even in the face of every preventative measure, some people with extremely high genetic risks may still go on to develop an eating disorder after just one or two triggering events that are outside of their control. Others with low genetic risk may show resilience to developing an eating disorder even in the face of many potential environmental risk factors.

When someone develops an eating disorder, it's no one's fault. The cause of eating disorders is too complex to attribute blame to any one person, event, or gene.