Nutrition and Autism, Research and Guidelines

Nutrition and Autism, Research and Guidelines

Nutrition and Autism

Research and Guidelines as Told by an Autistic Bloke

By Charlie Cooke,
ANutr and Head Coach at Union Jab

This article was originally published in Complete Nutrition magazine Vol.21 - No. 9 - Dec/Jan 2022 - Page 61-63

Hello readers, I’m Charlie. This is my first time writing for Complete Nutrition Magazine, and I’m very excited as I have read this publication since I undertook my first nutrition diploma at university a good few years back. It’s a great honour to be able to take part because this magazine holds such significance in attracting eyes away from blog-based dietary rules and regulations, and instead focus on factual information from qualified professionals.

This makes CN especially significant for ‘yours truly’, as it was my obsessive nature in relation to other health and fitness publications that led to me becoming a nutritionist, boxing coach, and overall ambassador for good health habits – such as when where I was working ‘on the inside’ for a fitness publication and editing their information to be more accurate before it went out… (don’t tell my old boss).

The purpose of this article is to bring you, the readers, up-to-date with the latest information on the relationship between nutrition and autism and how they interact with each other, in varying measures, affecting not only the severity of the condition but also the overall health of the individual. As I was diagnosed with Asperger Syndrome at a young age – now classified as Autistic Spectrum Disorder (ASD) – and have an almost complete inability to always stay formal and professional, I thought it’d be a fun exercise to approach this with some personal interjection when points can be, have been, and/or are relevant to my own condition.1

This does come with some pitfalls, however, as autism is considered a ‘spectrum disorder,’ meaning that there is a large variation in the number and severity of different symptoms. These symptoms are repeating trends in behaviours that are monitored, tracked, and used as the basis of diagnosis in the Diagnostic and Statistical Manual of Mental Health (DSM). The DSM is reviewed regularly and therefore  some conditions become defunct over time, in my case as Asperger’s autism along with others were banded into a single condition now termed ASD in the DSM version 5 as it replaced the DSM v.4.1,2

The way I find myself explaining the diagnosis process is to consider a checklist of potential behaviours and symptoms relating to a person’s condition. This list is very long, so no one person will typically tick every box, but they will certainly tick a mix of boxes. Once they tick enough boxes of behaviours related to ASD then we may be able to proceed with a diagnosis and then consider this person autistic.

The clinical diagnostic dyad of conditions as described in the DSM-5 is as follows:

ASD is clinically present before the age of three years with symptoms concerning mainly two areas which are restricted, repetitive patterns of behaviours, interests, or activities, and persistent deficits in social communication and social interaction”.2

As there are such drastic differences in exhibited behaviours it can make it difficult to produce precise guidelines on how to manage the condition. This was made evident in a survey conducted in Australia asking dieticians on their success in implementing feeding strategies in children with ASD, as it showed a limited to average knowledge of feeding methods and demonstrated the need for implementation of autism-related clinical guideline.3

Yet, there are common trends in dietary behaviours of which we can be aware. The BDA highlights such common conditions as:4

  • Not liking mealtimes and only eating a few foods.
  • Constipation, diarrhoea and a bloated stomach.
  • Food hypersensitivity – when the body reacts badly to certain foods.

This is consolidated by a review of 44 research studies which demonstrated restricted dietary variety, food neophobia (fear of new foods), food refusal, limiting one’s diet based on texture, and a propensity towards being overweight in children diagnosed with ASD.5,6 Although there were indications from respondents that such factors become more manageable with age, it was still found that such dietary behaviours do continue into adulthood and continue to influence the increased risk of negative health factors, both mental and physiological, in autistic adults.7,8

I for one can certainly relate to factors of food selectivity, especially as I was once the typical ‘gym bro’ that got into fitness and nutrition from the so-called ‘rules’ of gaining muscle and the restrictive male athlete diets from consumer/lifestyle magazines. I later discovered, having worked for the very same bodybuilding magazines I was ‘reference reading,’ are too often written from off the top of an editor’s head, who has no formal education in nutrition.

Although such selective and restrictive dietary behaviours are common, when food selectivity is defined as food refusal, limited food repertoire, and high frequency single food intake, it is found that food selectivity is exhibited more strongly in children with ASD than in typically developing children.9

This selective behaviour may lead to many detriments to health through insufficient intakes of key nutrients for development, as is further demonstrated in the results of research collected from children with ASD aged two-to-eleven years which found:10

“Children with ASD and matched controls consumed similar amounts of nutrients from food. Only children with ASD aged four-to-eight years consumed significantly less energy, vitamins A and C, and the mineral zinc; and those nine-to-eleven years consumed less phosphorous.”11

Yet, food selectivity is not the only measure of difficulty we must manage when attempting to assist individuals with ASD. Gastrointestinal (GI) symptoms are also a far more common issue in those with ASD, as was confirmed in a meta-analysis spanning over 32 years of research conducted in the field, despite there still being an inadequate understanding of the causes and impact of such GI distress.12,13

The most common issues are highlighted in Figure 1, as seen in a brilliant research review by Jolanta Wasilewska and Klukowski, 2015:


At the outset of this article, I mentioned that we must consider how the condition may influence the diet of the individual and vice versa, however, it is also important to note that there are other matrices of interaction that may exacerbate symptoms in all directions. For instance, it is noted that such GI distress may be related to typically associated autistic behaviours such as facial grimacing, gritting teeth, sobbing, and delayed echolalia. Thus, this factor adds further complication to the diagnosis and treatment of such conditions, especially when considering factors such as limited verbal and non-verbal communication skills, and an altered response to pain as described in a consensus report in Paediatric. 5,14,15

As the relationship between the specific, direct mechanisms of ASD and GI distress are as yet undefined, Jolanta Wasilewska and Klukowski proposed that we may instead consider the relationship as ‘a possible new overlap syndrome’. Their research journal highlights the many factors influencing symptoms, diagnosis, and treatment and I’d highly recommend reading it for more information specific to ASD and GI complaints.

Specifically, their guidelines for clinical practice, especially in regard to rebalancing the gut microbiota through probiotic interventions in order to assist in the gut-brain relationship as the neurocrine and endocrine pathways modulate: “appetite and energy homeostasis, stress response, emotions and attitude, learning and memory, and response to pain”. 16,17

Additionally, interventions such as the elimination/reintroduction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) may also provide key benefit due to the potential overlap of ASD with non-celiac gluten sensitivity.18,19

Therefore, when implementing guidelines for those with ASD, we must consider that we may be working with an individual with a propensity for rigid dietary practices, aversions to specific foods/textures, a genetic predisposition to GI conditions which may worsen existing ASD-related behaviours, and a lowered ability to accurately explain their complaints and habits due to affected social understanding and exhibited behaviours.

Yet, speaking entirely subjectively and of my own opinion and experience, I believe there are benefits to, and from, an autistic mind in relation to dietary management which may be capitalised upon, should we be willing to work with such behavioural predispositions.

As I’ve noted earlier, the ‘rules and regulations’ of the fitness industry bloggers and/or their associated magazine content created the perfect storm for my own autistic mind which was easily influenced as a child and teenager. The diets this industry advocated were already restrictive and repetitive, and thus by following this pattern, as was second nature to me, my diet now felt like success, as opposed to failure in not adding variety. Further, the belief that consistency equals results made this rigid dietary pattern far more suitable and sustainable to follow in the blind belief that eating a prescribed metric of protein, carbohydrate, veggies, and water every two hours would guarantee results. Therefore, in my adult life, I find the addition of rulesets when training for, say, a boxing bout, to be highly beneficial as there is a routine to adopt in which I can add metrics of variety.

For instance, if we take an individual with a textural predisposition to soups, stews and casseroles, we could then modulate a diet based on a three-day batch cook of a chicken casserole with five vegetables and chicken stock. We then repeat this three days later using red-meat to, say, ensure iron intake and a different five vegetables of similar texture when cooked, thus introducing a wide variety, and density, of nutrients into a person’s diet as-well as assisting with adequate hydration.

We could then pair this with the staged removal/reintroduction of FODMAP containing foods in order to assist in the reduction of GI distress, alongside the introduction of a daily palatable probiotic supplement in order to assist the gut-brain matrix and thus reduce the severity of related symptoms, as found in a study with similar methods lasting 12 months including both children and adults with ASD which found: “significantly greater improvement in autism symptoms and developmental age” following dietary intervention.20

Let’s hope this example dietary intervention is successful, as this autistic bloke is headed back into the boxing ring, at the time of writing, in order to raise funds for my boxing business Union Jab to help get those with autism, and similar conditions, towards good exercise and dietary habits. All it takes is reading a good few resources and a bit of practice to help those less able than us to increase their health for good.

We're always here to answer questions if anyone is stuck with their diet and offer 121 nutrition and health counseling from our office in Greenside or online. This can be anything from just having your body fat assessed through to full dietary intervention. Often one session every few weeks is enough to keep people on track to their goals.

You can get info and pricing for all such 121 services at


  1. (2021) NIMH - Autism Spectrum Disorder. Accessed at: [15 November 2021].
  2. org (2021) DSM-5 Accessed at:> [15 November 2021].
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