Written by Lily Moorhouse, TCN Intern & Talia Cecchele, Highly Specialist Dietitian & TCN Founder
Autism & Eating Disorders
There is an increasing awareness and research to support the link between eating disorders and Autism Spectrum Disorder (ASD) or Autism Spectrum Condition (ASC). This area of research is in its infancy, however we are starting to understand how treatment could differ for people living with both ASD and an eating disorder.
Please note for the purpose of this blog we will be using the abbreviation ASD, however we acknowledge that ASC is also widely used and often preferred by some people living with a neurodiversity diagnosis. We ourselves are continuing to learn about ASD and we might not get the terminology exactly right.
What is Autism Spectrum Disorder?
ASD is a neurodevelopmental disorder which affects how people communicate and interact socially. It is estimated that 1 in 100 people or over 700,000 people in the UK have autism (1).
The current diagnostic criteria, as outlined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) defines autism as: "persistent difficulties in social communication and social interaction" and "restricted and repetitive patterns of behaviours, interests, or activities", of which "limit and impair everyday functioning" (2). You can read more about the different diagnostic tools and criteria on the National Autistic Society.
Characteristic Traits of Autism Spectrum Disorder
A person with ASD may experience difficulties with social communication, emotional regulation, changes in routine and increased sensitivity to surroundings and senses (taste, touch, light or sound) (2). In some cases, a person may become so overwhelmed by their environment or challenges in communication that they experience a meltdown or a shutdown (2). Autistic people might develop a high level of focus towards a special topic of interest that can impact daily life.
ASD is a spectrum and therefore every person will have a different experience of what it means to live with the disorder. However, as the world is built for neurotypical people, it can be difficult for people with autism to navigate many areas of their life, including their own mental health.
Is There a Link Between Autism & Eating Disorders?
The PEACE Pathway is a fantastic research project which provides resources and information about autism and eating disorders. Research from PEACE, predicts that around 35% of people living with an eating disorder also have autism or high autistic features (3).
There are two main eating disorders which have been better researched when it comes to the link with autism; avoidant restrictive food intake disorder (ARFID) and anorexia nervosa (AN).
Autism and Avoidant Restrictive Food Intake Disorder
ARFID is an eating disorder in which a person avoids specific foods, or types of foods due to sensitivities, fear of situations such as vomiting or choking, or a lack of recognition of hunger (4). Studies suggest that approximately 20% of people with autism also have ARFID. Additionally, of children diagnosed with ARFID, it was predicted that 8.2-54.8% are autistic (5). Due to difficulties with autism diagnosis, this is a huge range, highlighting the need for more research in this area.
Autism and Anorexia Nervosa
A review of the prevalence of autism amongst people with anorexia nervosa found that 28% of people with anorexia showed symptoms consistent with autism, compared with 4% of those with no history of mental health problems (6). Studies considering autism and anorexia have shown that autism symptoms were not related to weight, or how long the individual had been unwell. This suggests autistic symptoms in people with anorexia are not due to effects of starvation or low weight, and may actually be traits present before and after the illness (7).
What are the Common Traits Between Autism & Eating Disorders?
We summarise the main ASD traits and how these might this impact a persons relationship with food, and behaviors that we commonly see in some eating disorders in the table below.
Difficulty experienced in ASD | What it is? | How it impacts people living with ASD and an eating disorder | Possible consequences or challenges |
Interoception | Ability to recognise internal physical or emotional states such as hunger or a racing heart | More likely to miss meals due to a lack of hunger or have increased anxiety around their experience of hunger due to hypersensitivity. | Food restriction or difficulty in eating enough. |
Sensory sensitivity | Hypersensitivity to tastes, textures, smells, sound, temperatures, touch | Avoid certain foods due to taste, texture, smell or the environment around them. Strict rules or rituals around meal times Restriction to numb sensations | Reduced diet variety and adequacy (eating enough) Nutritional deficiencies Anxiety when in an unfamiliar environment or when faced with new foods Can only eat in safe and well known places |
Cognitive inflexibility | A need for control | Rigid food rules e.g. only eating a certain brand of bread as this is safe | Rigid beliefs about food and obsessive behaviours might develop Limited food variety Increased anxiety and distress around food Unstructured or spontaneous eating can cause anxiety |
Social interaction | Difficulty forming friendships and understanding others | Avoiding eating in social situations Restricting or bingeing as a distraction | Social isolation, small recovery/support network Avoid social eating |
Self and identity | Lack of a sense of self | Food is used as a cooping mechanism, something that can be controlled | Dietary restriction Being at an unhealthy weight |
Difficulties with emotions | Overwhelm leading to meltdowns or shutdowns | Food is used to numb feelings or regulate emotions | Unhealthy coping mechanisms are developed such as binge eating |
Literal/rigid thinking | All or nothing mindset | Food rules become rigid and difficult to break Obsessive and intense interests may be in food and exercise | Obsessive behaviours such as calorie or step counting |
Need for control | Prefers predictable situations | Control over food intake | Unstructured or spontaneous eating can cause anxiety Unknown foods can cause anxiety |
(8-10)
Treatment of Autism & Eating Disorders
Based on the field’s limited understanding of eating disorders and autism, there is a lot to learn about how we can tailor treatment to support recovery from an eating disorder. Unfortunately, in the past (and still today) some people might receive treatment recommendations which do not factor in the specific needs of challenges that people with autism face. For example, it is common for eating behaviours such as restriction or selective/fussy eating to be attributed to the eating disorder, instead of being recognised as an ASD characteristic and visa versa (11,12).
The PEACE Pathway is an incredible step in the right direction, in modifying the treatment of an eating disorder in combination with ASD. Dietetic considerations and adaptations might include:
adapting the diet to meet sensory challenges for example creating a "bland" or "beige" diet consisting of white, yellow and orange foods if a person has strong aversions to red or green foods.
building an adequate meal plan and diet with safe foods (for example specific brands) and using a graded approach or food-chaining to increase food variety
changing the meal environment to make it safe and predictable e.g. playing music, being seated at the same position on the table, being served with the same sized plate
creating a meal plan that is predictable and repetitive, and using photographs of food to reduce anxiety
planning social outings at a high level and practicing the meal in a safe environment before hand to reduce anxiety
using recipes that are easy to follow to encourage safety and predictability
Some of the nutritional considerations overlap with other neurodivergent disorders such as Attention Deficit Hyperactivity Disorder (ADHD).
ASD is not a "curable" condition, and whilst it can make many aspects of life more difficult, it is also part of who a person is and common traits can be reframed as a special characteristic that can be learned to be used to a persons advantage.
If you need support in your recovery, we offer 1:1 support at the TCN clinic. You can find out about more about how we can support you here.
Lily Moorhouse (TCN Intern) & Talia Cecchele (TCN Founder)
Talia Cecchele Nutrition is a team of registered dietitians that specialise in eating disorder recovery, disordered eating, digestive issues and sports nutrition. We aim to bring balance back to nutrition, help you to break free from food rules and find food freedom. We offer virtual consultations and group programs so whether you are based in London, the United Kingdom or around the world we would love to support you. To enquire about a private consultation please fill out a contact form.
REFERENCES:
1 American Psychiatric Association, 2013. Diagnostic and Statistical Manual of Mental Disorders (DSM-5®). 5 ed. Washington: American Psychiatric Publishing.
2 The National Autistic Society, 2023. What is autism?. [Online]Available at: https://www.autism.org.uk/advice-and-guidance/what-is-autism[Accessed 12 December 2023].
3 PEACE Pathway, 2020. PEACE Pathway. [Online]Available at: https://peacepathway.org/[Accessed 12 December 2023].
4 Bryant-Waugh, R. (2019, August 2022). "WHAT IS AVOIDANT/RESTRICTIVE FOOD INTAKE DISORDER?" 2nd. Retrieved 2nd January 2023.
5 Keski-Rahkonen, A. & Ruusunen, A., 2023. Avoidant-restrictive food intake disorder and autism: epidemiology, etiology, complications, treatment, and outcome. Current Opinion in Psychiatry, 36(6), pp. 438-442.
6 Kerr-Gaffney, J., Harrison, A. & Tchanturia, K., 2020. Autism Spectrum Disorder Traits Are Associated with Empathic Abilities in Adults with Anorexia Nervosa. Journal of Affective Disorders, Volume 266, pp. 273-281.
7 Kerr-Gaffney, J., Harrison, A. & Tchanturia, K., 2020. The Social Responsiveness Scale Is an Efficient Screening Tool for Autism Spectrum Disorder Traits in Adults with Anorexia Nervosa. European Eating Disorders Review, 28(4), pp. 433-444.
8 Li, Z., 2020. Interoception: the ‘hidden’ sense. [Online]Available at: https://peacepathway.org/blog/interoception-the-hidden-sense[Accessed 12 December 2023].
9 Brede, J. et al., 2020. “For Me, the Anorexia is Just a Symptom, and the Cause is the Autism”: Investigating Restrictive Eating Disorders in Autistic Women. Journal of Autism and Developmental Disorders, 50(12), pp. 4280-4296.
10 Baraskewich, J., von Ranson, K., McCrimmon, A. & McMorris, C., 2021. Feeding and eating problems in children and adolescents with autism: A scoping review. Autism, 25(6), pp. 1505-1519.
11 Mayes, S. D. and H. Zickgraf (2019). "Atypical eating behaviors in children and adolescents with autism, ADHD, other disorders, and typical development." Research in Autism Spectrum Disorders 64: 76-83.
12 Samuel, T. M., K. Musa-Veloso, M. Ho, C. Venditti and Y. Shahkhalili-Dulloo (2018). "A Narrative Review of Childhood Picky Eating and Its Relationship to Food Intakes, Nutritional Status, and Growth." Nutrients 10(12).