Autism, Atypical Eating Behaviors and Eating Disorders

Atypical eating behaviors are common in autistic people. According to a study by Mayes & Zickgraf, 2019, 70.4% of autistic children have atypical eating behaviors as compared to 13.1% for other disorders and 4.8% for typical children. They found that only autistic children had pica or pocketed food. For 92% of autistic children, the most common preferred foods were grains and chicken, mainly nuggets.

Autistic individuals may be very selective about what they will eat and may be sensitive to texture, smells, the look, or sounds of certain foods. Some autistics may have misophonia which is an extreme sensitivity to certain sounds such as chewing or slurping. Someone who finds such noises triggering may not be able to eat in a restaurant or at the family table. The social aspects of eating such as making small talk and waiting for everyone to finish eating before leaving the table may also present challenges.

Oral motor problems can make chewing and swallowing difficult. Shirley Sutton, Canadian occupational therapist, wrote a great article entitled Oral Motor Fun that addresses these issues. Once a child’s hypo or hypersensitivities are recognized, activities can be planned accordingly to help with oral motor challenges.

Up to 70 percent of autistic individuals have gastrointestinal (GI) abnormalities at some point during childhood or adolescence. They are also more likely to have constipation or chronic diarrhea than children who are not autistic. A 2013 study by the UC Davis MIND Institute led by Virginia Chaidez found that autistic children experience gastrointestinal (GI) upsets such as constipation, diarrhea and sensitivity to foods six-to-eight times more often than do children who are developing typically.

Because many of these symptoms and behaviors are commonly seen in people with eating disorders, researchers are trying to further understand the relationship and prevalence of autism in people with eating disorders (and vice versa), particularly in females who have a higher rate of eating disorders and are often underdiagnosed with autism.

The most common eating disorders for autistic people are anorexia nervosa and avoidant/restrictive food intake disorder (ARFID).  Let’s explore each of these in more detail.

Autism and Anorexia Nervosa

In 1983, Christopher Gillberg, professor of child and adolescent psychiatry at the University of Gothenburg in Sweden, first posed the question in the British Journal of Psychiatry: Could autism and anorexia nervosa share underlying causes? He asked this question because he observed similarities between the two disorders. Girls with anorexia and/or autism displayed greater inflexibility, social difficulties, lower empathy and a greater tendency to systemize (create and follow rules) than other people. Other similarities observed were a strong interest in details and systems, a tendency to focus on themselves and inflexible behaviors and attitudes.

The Brede et al. 2020 study found that 20-35% of women with anorexia met the diagnostic criteria for autism, with many others exhibiting higher levels of symptoms characteristic of autism than the general population without actually meeting the threshold for a diagnosis.

Body image may be less of a concern for autistic people with anorexia, but restricting food intake may be used as a coping technique to mask emotions and anxiety. Repetitive behaviors can take the form of an intense interest such as calorie counting or excessive exercising which develops into anorexia over time.

Avoidant/restrictive food intake disorder (ARFID)

In the DSM-V, the definition of avoidant/restrictive food intake disorder (ARFID) is an eating or feeding disorder characterized by a persistent and disturbed pattern of feeding or eating that leads to a failure to meet nutritional/energy needs. Like anorexia, a person restricts their food intake but the intent or reason behind the restriction is different in that people with ARFID do not restrict food in order to avoid weight gain/control their body shape/size.

ARFID is more commonly seen in children and adolescents, but adults can present with it too. ARFID is sometimes called ‘extreme picky eating,’ and may be the most appropriate diagnosis for some autistic people who are underweight or have trouble eating.

Treatment and recovery from eating disorders for autistic people

Eating Disorders Victoria, Australia says:

Identifying the presence of autism can make treatment and recovery of the eating disorder more effective.  Autistic people experiencing eating disorders may need access to a treatment plan that is not only aware of their autism, but actively understands it and allows treatment to be responsive to the needs of the individual.  

Standard eating disorder treatments tend not to accommodate the specific needs of autistic people. They may focus too heavily on weight or body image, involve overwhelming group settings, inpatient stays that disrupt routines and the need for in person visits to medical clinics that may be brightly lit, noisy and unfamiliar. Treatments that require a person to make dramatic changes to their eating routines in a short period of time may also be ineffective for people with autism who simply require more time and a more gradual process of change.  Autistic people may require less food choices and more clarification around rules and expectations in recovery.

Other aspects to understand about autism and eating difficulties

Interoception and internal body states

Interoception is the 8th sense that helps a person understand what is going on inside of the body like hunger, thirst, feeling hot or cold, fatigue, or a full bladder. It also affects the ability to interpret emotions; butterflies in the stomach may not be felt as anxiety or nervousness. Not understanding this sense can make self-regulation a challenge and can be a factor in eating difficulties. Autistic people may have trouble recognizing when hungry or full. Neither of my adult autistic children has ever told me they are thirsty or hungry. They have never gotten themselves a drink of water nor asked for one, so I send a water bottle with them to all activities and offer water throughout the day.

Occupational therapist Kelly Mahler is doing brilliant work on the topic of interoception and its connection to eating disorders. Her interview with autistic Kim Clairy, who is in eating disorder recovery, sheds light on the connection between dysregulation and not being able to eat. Kim says:

So things that I’ve had to learn for recovery is that I need to make sure that I’m regulated, I have to take breaks all throughout the day and assess where I’m at and my level of regulation. If I need to take a break before a meal, that’s okay. If I need to take a break in the middle of a meal, that’s okay.

It can be really hard to sit still for that long. The last thing I want to do is sit down. It’s like my body just doesn’t like it. Wearing weighted stuff can help, but it takes a lot of energy to sit and remain seated. And if I don’t have that focus energy, if I’m not regulated cognitively as well as sensorially, then I’m not going to be able to sit. I’m just going to walk around, which sometimes you have to. Sometimes I have to eat while I’m pacing, or I use a rocking chair at our table while I eat, and that has been working really well, actually.

Alexithymia

A core feature of people with eating disorders is that they find it difficult to identify and cope with emotion. Alexithymia is common in autism. Not understanding emotions that are being felt and being able to communicate feelings to others can make it hard for a person to soothe themselves or get support from others. This can increase the vulnerability to developing an eating disorder as a coping mechanism.

Routines and rituals around eating

Autistic people like to have predictability in their day and environment; meals and snacks are no exception. The presentation of food may have to be a certain way. Eating can follow a rigid schedule. Foods may have to be prepared a certain way or have to be a particular brand. (We had this dilemma with Ragu plain pasta sauce which was discontinued in August 2020).

My two children eat their lunch and dinner from a white bowl. Foods can’t be mixed together, but have to be presented beside each other though they can be touching. Snack time is at 4 pm and consists of pretzels for my daughter and plain popcorn with water to drink for my son. Both have improved a lot with trying new foods, but for years their diet was the same 10 foods or less. My daughter recently added fruit to her diet in January 2022 after being told by her doctor that she had low blood pressure. She thought that eating fruit might improve that.

If you are looking for more ideas on how to expand a limited diet, check out my blog post on this topic.

If you have concerns about an autistic person’s eating and nutrition, please seek professional help. An individualized treatment plan for an eating disorder will need to be developed by a trained professional.