Special diets and autism

Thousands of parents have placed their children on special diets according to the Autism Research Institute (ARI). It is a controversial approach that divides opinion, however, parents using this approach have reported improvements in cognition and social connection. This feedback is often enough to make other parents want to try a dietary protocol for autism, but how do you choose the right diet for your child? Is one approach more effective than another?

The ARI has collected information from parents regarding the effectiveness of specific diets and their statistics suggest that the following protocols are the most effective. The Specific Carbohydrate Diet (SCD) or the similar Gut and Psychology Diet (GAPS) diet is considered the most effective with 71% of parents reporting improvement. This is followed by the Gluten and Casein Free Diet (69%) and in third place is the Feingold approach with 58% reposting an improvement. We take a closer look at these nutritional interventions, what they involve and when to try them.

Specific Carbohydrate Diet (SCD) / Gut and Psychology Syndrome (GAPS)

What's involves

Removal of grains, some starchy-vegetables and some beans. The focus is on removing foods which might irritate the gut, foods that are more taxing on the digestive system. The protocol also focuses on re-establishing appropriate gut bacteria. Probiotics and fermented foods are used along with some basic supplements.

These protocols, in theory, allow some forms of dairy products to be eaten. However, it is often useful for a child to have a trial of dairy elimination for a short while to rule out casein sensitivity.

When to try it

SCD and GAPS are good protocols when there are strong digestive issues present - loose stools, mucus in stools or severe bloating, or when you suspect that digestive discomfort is an ongoing problem. These protocols are also useful when or if progress plateaus on another therapeutic diet. It is a good idea to rule out oxalates as an issue before trying this diet.

The SCD and GAPS approach can sometimes contain plenty of oxalate rich foods which may cause problems for some. You can rule out oxalates as a problem by running an Organic Acid Test (OAT). It needs to be one that looks at oxalic, glycol and glycerin metabolites, so check with your practitioner if you’re not sure.

Gluten and Casein free diet

What it involves

Removing all dairy from cow’s, goat’s and sheep etc. and removing all sources of gluten (wheat, rye, barley and oats). With the wide availability of gluten and dairy-free products, the process of replacing a gluten or dairy-based product with a free-from alternative is generally easier than before. It is important to be strict in avoiding these foods as any small infraction can affect progress. This is a good diet for noticing improvements in cognition and behaviour. Be mindful of using soya based products as dairy alternatives as these can be difficult to digest.

When to try it

This is often the first port of call for many parents of children with autism. Some parents worry that this approach could be difficult to implement being due to gluten and dairy containing foods generally being preferred by children on the spectrum. However, after some time avoiding gluten and dairy containing foods for some time, most children become less ‘picky’. You will also need to consider the general nutrient content of your child’s diet if you are simply switching foods - but this is a good place to start, especially with picky eaters.

Feingold diet

What it involves

The removal of additives and only allowing a low level of phenol and salicylate-rich foods. A number of children on the spectrum react to phenols in foods as well as chemical additives in foods. The Feingold diet allows a trial removal and reintroduction of phenol rich foods and elimination of additives.

When to try it

This is a useful diet when hyperactivity is a big issue, or when a child is exhibiting minor tics or obvious reactions to chemicals and additives. I recommend removing chemical additives from all children’s diets initially - whichever diet you decide to try. However, this diet is useful if, after trying another diet, you suspect your child is still reacting to phenols and/or salicylates. You cannot test for phenol sensitivity but you might recognise the following signs in your child:

  • A strong craving for phenol /salicylate-rich foods (like apple juice or grapes).
  • Aggression or self-injury.
  • Tantrums or hyperactivity after consuming phenol-rich foods or additives.
  • Red cheeks and ears at times.
  • Inappropriate laughter.


The protocol you choose will depend on your child’s current health issues and their reactions to specific foods and their removal. A nutritional therapy practitioner can help you decide on the best way forward for your child and help devise an individual protocol for your child. This will include a specific dietary protocol, any necessary supplements and appropriate testing too.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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Birmingham, B13 8JP
Written by Sarah Hanratty
Birmingham, B13 8JP

Sarah is an experienced practitioner at the Brain Food Nutrition Clinic specialising in the link between gut health and physical and cognitive well-being.

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