Autism And Eating Disorders Overlap, But We Don’t Yet Know Why

As more people are diagnosed with autism or eating disorders (or both) globally, understanding their connection becomes even more critical.

People are often diagnosed with an eating disorder and autism. This may come as no surprise to people with autism and their loved ones. One trait of autism is being hyper-aware of senses, like smell and taste. Not all people with autism experience this, but those who do might find it affects their diet.

It has been shown that disordered eating in people with autism goes hand in hand with the number of autistic traits and behaviors they have.

One study found that people with mild to moderate autism were more than twice as likely to have food-related difficulties.¹

Among the participants, 39% reported “problematic behavior,” compared to 15% who didn’t experience challenges. People with severe autism were very likely to report the same (46% compared with 0%).

Autism and eating disorders are different diagnoses

There are apparent differences between the two diagnoses. People with autism experience a different way of life. This is sometimes called “neurodivergence.” The main difference between eating disorders and autism is that the way autistic people experience life is not a medical problem.

On the other hand, an eating disorder is a mental health condition, not a type of neurodivergence. It may present as a “different way of thinking,” but not in the same way.

A symptom of eating disorders is making up “rules” about food that are nonsensical to others. Another is having strong feelings about your body, diet, and exercise.

Unlike autistic neurodivergence, the “rules” and feelings associated with eating disorders are abnormal. They are harmful. Eating disorders can result in physical harm, which isn’t always the case with neurodivergence.

Autistic people are more likely to experience eating disorders

We have known for some time that people with autism are more vulnerable to anorexia and other eating disorders. Substantial evidence now shows autistic traits correlate with disordered eating behaviors.

The relationship between autistic traits and disordered eating is not yet well understood. However, a trait called alexithymia is thought to be an essential link between the two conditions. This is when a person struggles to know, understand, or describe their feelings.²

Eating disorders are common in children with autism

Disordered eating behaviors are common among children with autistic traits. A 2020 study of over 5,000 teenagers found that autistic traits in children could predict eating disorders in teenagers. This was the first long-term study to examine this association.³

Avoidant restrictive food intake disorder (ARFID)

ARFID is associated with one or more of the following features:

• Not having enough energy due to not eating enough

• Weight loss (in adults) or failure to gain weight (in children)

• Struggling to cope with life and relationships

• Dependence on supplements⁴

People with ARFID don’t tend to be confused about how they look, nor do they have an illness that stops them from eating.

Physical symptoms of ARFID include stomach cramps, period changes, and unusual lab findings (such as anemia or low hormone levels). People with ARFID might also struggle to concentrate and sleep or feel dizzy, faint, and cold all the time.

The National Eating Disorders Association (NEDA) draws parallels between ARFID and anorexia symptoms. Both eating disorders indicate a person isn’t meeting their body’s needs for food and vitamins.

Autism and anorexia often overlap

Researchers first suggested autism and anorexia were linked in 1983.⁵

In 2017, a review found that studies often spot symptoms of autism spectrum disorders (ASD) in people with an anorexia diagnosis.⁶

While authors said it was difficult to determine the prevalence of ASD in people with anorexia, they said they would recommend people with both diagnoses get more intensive treatment or special interventions. The authors also called for further research, particularly into new ways to diagnose autism in women and girls.

Restriction as a way to cope

People with autism report using restrictive eating as a way to cope with stress. This behavior is often autism-related.

Participants in a 2020 study were found to use restrictive eating to cope with autism-specific stress. This included noise sensitivity, light and textures, emotional and social difficulties, trouble coping with uncertainty, needing a lot of rigidity/routine, literal thinking, and intense interest in food, weight, and exercise.⁵

The authors discovered that restriction led to participants “numbing down” or “resolving” sensory or emotional experiences. It also “introduced calmness” through control and predictability.

Eating disorders affect two in 1,000 people worldwide

In a 2016 review, 18.5 people per 10,000 were estimated to have ASD worldwide. This is up from estimates in the 1980s that reported autism affected just five people per 10,000.⁷ ⁸

Since 1990, the prevalence of eating disorders has risen in many countries, including Australia, New Zealand, Canada, South Korea, India, China, and the UK.⁹

The global prevalence of eating disorders is estimated to be 0.2%, equivalent to 20 in 10,000.

In the last few years, experts have noted that stressors during the COVID-19 pandemic may have contributed to a recent rise in cases. More cases were serious enough to need treatment. 

Pandemic-related disruption—including disrupted treatments for eating disorders—may have also created mental health challenges. In turn, this may have caused symptoms to return or worsen.

Autism and eating disorders have raised concerns over the past decades because diagnoses have risen without a clear reason. One simple explanation is that clinician, patient, and public awareness has improved, resulting in more diagnoses. Still, further research is needed.

We need more research and specific treatments

More research and specialized support would help people with eating disorders and autism. One example of specialized support could be teaching doctors about the link between difficulty talking to people and eating disorders.³

More research would help us better understand why restrictive eating helps autistic people cope with stress and the relationship between autistic traits and disordered eating behaviors. It might also shine a light on condition-related gender gaps.

Eating disorders are extremely dangerous. A 2020 review reported that, despite advances in treatment, people still die from anorexia and bulimia.¹⁰

More research and evidence-based treatments could reduce harm and save lives.

Sources:

1. Feeding problems in children with autism spectrum disorders (2018)

2. Alexithymia may explain the relationship between autistic traits and eating disorder psychopathology (2020)

3. Trajectories of autistic social traits in childhood and adolescence and disordered eating behaviours at age 14 years: A UK general population cohort study (2020)

4. Avoidant restrictive food intake disorder (ARFID) | National Eating Disorders Association (NEDA)

5. “For me, the anorexia is just a symptom, and the cause is the autism”: Investigating restrictive eating disorders in autistic women (2020)

6. Autism spectrum disorder in anorexia nervosa: An updated literature review (2017)

7. Prevalence of autism spectrum disorders in a total population sample (2011)

8. The epidemiology of autism spectrum disorders (2007)

9. Share of population with an eating disorder | Our World in Data (2019)

10. Review of the burden of eating disorders: Mortality, disability, costs, quality of life, and family burden (2020)