Anxiety autism children's health eating disorders Gut health

Autism: Why will my child only eat certain foods?

Selective eating and autism.

It is not unusual to find children with selective eating habits and it is very common in children with autism. Restricting food intake to a limited number of foods and refusing to eat other foods is a common issue in families with a child with autism. There is a complex interaction of factors influencing food choice. These include anxiety, heightened sensory issues, genetic factors, digestive issues and nutritional deficiencies.


It is usual for children to go through a ‘beige’ food stage at around twenty months old. Evolutionary theory suggests toddlers prefer to choose foods that are considered safe and familiar. This is when a baby who has eaten almost anything now chooses to eat only potato, toast or similar types of food. At this stage a child is hypervigilant when it comes to food and may concentrate on small details of food and how they differ. Some researchers think that this stage is characterised by sensory hypersensitivity and anxiety. Some children, don’t grow out of this phase and sometimes it persists into adulthood. The longer selective eating occurs the more detrimental its effects can be on physical and mental health.

Selective food intake has been associated with anxiety, depression and ADHD/ADD in young children. Where there is anxiety around food, a child will choose foods that are familiar in taste and texture. Sometimes this anxiety stems from hypersensitivity to taste and texture. When anxiety or depression leads to selective eating, the eating pattern becomes more severe as these conditions worsen. Good nutrition plays an important role in mental well-being. Selective, imbalanced diets will most likely cause existing issues to worsen. It is not unusual to have to use carefully chosen supplements in the first instance to help a child with selective eating.

Sensory Issues.

Sensory issues around food – preferring crunchy foods, or maybe not liking these and preferring a certain taste of texture. Recent research suggests that is children with greater sensory issues that become more selective in their food intake. This would explain how sensory sensitive children become fixated on a very narrow diet. Children with sensory issues may choose their food according to its texture (crunchy or smooth) and whether it is consistent –  only liking smooth sauces or avoiding smoothies with pips in. Does your child gag when they come across a piece of tomato or onion in a sauce? Or dislike mashed potato because they once came across a lump in it?

The tactility and smell of food can also be important. Does your child sniff food before eating it? This gives the child information on whether the food is likely to be offensive to them. Having these super sensory issues influences food choices in a big way. Gut bacteria, nutritional deficiencies, genetics and general gut dysfunction can all contribute to an increase in sensory issues in children with autism.

Low zinc levels have been linked to issues with taste. Foods can taste ‘different’ or bland leaving the texture of the food as the overwhelming factor. Food without any real taste is not very palatable and the ability to sense lumps or changes in texture becomes more prominent. Appetite can also be influenced by low zinc levels.

Gluten and casein peptides.

A long-standing theory in the history of selective eating and autism is the peptide theory. This theory suggests that children with autism have an enzyme deficiency that affects their ability to break down certain foods. The peptides in these foods are not processed properly by the body and are considered to exert an effect on cognitive function, an almost opiate-like effect. This leads the child to crave foods containing these specific peptides – namely gluten and dairy products. Parents who have implemented a gluten and dairy free diet for their child have reported that the ‘opiate-like’ effect which results in their child being spaced-out and less socially connected can be improved within six months on a gluten and casein-free diet.  If your child is eating mainly foods containing gluten and dairy then this is something to consider.

Diets consisting entirely of these foods are a common reason why parents say they cannot attempt a therapeutic gluten and casein free diet. When these are the only foods your child eats it can be difficult to consider removing them from the diet. Over time, on a gluten and casein-free diet children’s food choices tend to expand.

There is a test available to detect the levels of peptides in the urine of children, however, the best approach is to trial a gluten and dairy free diet for 6 months and analyse progress using a scale like the ATEC form ( at the Autism Research Institute. Although more research needs to be done in this area, anecdotal reports from parents are generally supportive of this type of dietary intervention.


    Sarah is a clinical nutritionist specialising in mental wellbeing and the gut-brain connection.

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