Diet and nutrition for autistic adults

When it comes to managing diet and nutrition for individuals on the autism spectrum, there is no one-size-fits-all solution. 

Each approach must be customised to support the person’s needs, abilities and preferences. It’s important to recognise that long-term restrictive diets will often eventually lead to nutritional deficiencies and can impact a person’s health and wellbeing. 

Understanding the challenges

Autistic adults often face unique challenges with diet and nutrition that can significantly impact their overall health and wellbeing. Sensory sensitivities are often an issue. Things like textures, tastes, or smells of certain foods can be overwhelming, leading to a limited and repetitive diet. For example, an individual might only eat foods with a specific texture, such as smooth or crunchy, and avoid others entirely. This selective eating can result in nutritional deficiencies if key food groups, like fruits, vegetables, or protein rich foods, are consistently avoided.

Many autistic adults have a strong preference for routine, which can extend to their eating habits. They may prefer eating the same foods at the same times each day, making it difficult to introduce a variety of healthy options into their diet. Only eating a narrow selection of foods can limit the intake of crucial nutrients and vitamins needed for a balanced diet.

Social and communication difficulties also play a role in these dietary challenges. Autistic adults might find it hard to seek advice or support about their nutritional needs, whether from healthcare providers, dieticians, or even family members. Miscommunication or discomfort in social situations can prevent them from accessing the help they need to make dietary improvements, or even being able to purchase the right foods or ingredients.

Additionally, co-occurring conditions such as anxiety or gastrointestinal issues, which are common in autistic individuals, can further complicate their relationship with food. Anxiety might cause a reduced appetite or comfort eating, while gastrointestinal problems can make certain foods painful to eat, leading to further dietary restrictions.

Addressing common food issues

Sensory experience

Many autistic individuals experience sensory differences, affecting their experience with meals and meal preparation. For those who are over-sensitive to sensory stimuli, environments like noisy environments can be too distracting. Modifying the cooking and eating environment, such as providing a quiet room or adding cushions to chairs, can help. Playing calming music or stories can also make mealtime more enjoyable.

Food presentation and preferences

The sensory properties of food—its smell, taste, and texture—play a significant role in how it is received by people with autism. Some may prefer bland foods due to sensitivity to strong smells and tastes, while others may seek out strong flavours. Modifying food textures, such as puréeing and introducing new foods gradually, can help make the person more comfortable trying a variety of foods.

Coping with discomfort and illness

Physical discomfort can significantly impact eating habits. Conditions like gut pain, constipation, heartburn, toothache, and the side effects of medications can all affect appetite and willingness to eat. Supporting individuals to communicate their physical discomfort using their preferred communication tools is important. Understanding what they need and how to provide accommodations can make all the difference. 

The importance of food presentation

Attention to detail and consistency in food presentation can significantly impact whether an individual with autism will eat it. Factors such as changes in food positioning, cooking levels, and packaging can be deal-breakers. Understanding these preferences and maintaining consistency can help reduce food-related stress and create more opportunities to try new foods. 

Social and environmental considerations

The social aspect of mealtimes can be either beneficial or stressful for autistic individuals. Some may eat better in the company of family or peers, while others may prefer eating alone. Setting expectations and providing details about the setting and participants can reduce an autistic person's anxiety about social meals.

Effective routines

Autistic individuals often have specific obsessions and routines that can influence their eating habits. While these can sometimes lead to rigid diets or over/under-eating, they can also be used positively. Incorporating special interests into meals, such as using themed plates or involving the person in cooking, can help encourage a more varied diet.

Addressing over-eating and under-eating

For those who over-eat, strategies such as reducing portion sizes, limiting access to food, and setting clear rules around eating out can be helpful. On the other hand, for those who under-eat, increasing food portions, involving them in food preparation, and using visual aids to express hunger and fullness can support better eating habits.

Understanding pica

Pica, or the ingestion of non-food items, is a dangerous and concerning behaviour in individuals with autism. This can stem from sensory needs, anxiety relief, or a misunderstanding of what is edible. Addressing pica involves a combination of medical, psychological, behavioural, and sensory strategies, including the use of safety measures, providing appropriate alternatives, and seeking medical advice.

Exploring the gut-brain connection

The gut-brain connection refers to the complex communication network linking the gastrointestinal system and the brain, influencing overall health and behaviour. Many autistic individuals experience gastrointestinal issues such as constipation, diarrhoea, and food intolerances. Emerging research suggests that these gut problems may not only affect physical health but also impact behavioural symptoms of autism. It has been suggested that gut health through diet and probiotics may improve quality of life for autistic individuals, at this time, the evidence is inconclusive. 

The gluten-free and casein-free diet

The gluten-free and casein-free (GF/CF) diet is popular among some autism communities, even though there is limited evidence supporting its effectiveness. While a GF/CF diet may help alleviate some gastrointestinal symptoms, it does not address the underlying conditions. If not properly implemented, this diet can result in decreased bone density, constipation, nutritional imbalances, and long-term malnutrition.

Professional support

A multidisciplinary approach is often required to manage eating issues in individuals with autism. Professionals who can help include:

• Dentists for addressing dental issues that affect eating
• Dieticians for assessing and treating dietary-related health problems
• Eating disorder clinics for specialised treatment
• Clinical psychologists or psychiatrists for behavioural strategies
• Occupational therapists for advice on managing nutrition at home
• Speech pathologist for feeding and swallowing issues
• Counsellors for addressing underlying psychological issues