3 Connections Between Autism, Diet, and Behavior

Autism is not caused by malnutrition or food-related challenges, but that doesn't mean there's no connection between autism and food. As a matter of fact, research suggests that food-related challenges have a significant impact on many people on the spectrum.

Father feeding little girl outside
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According to one study, "children with ASD exhibited more food refusal than typically developing children (41.7% vs. 18.9% of foods offered)." Another study concurs: "... children with autism have significantly more feeding problems and eat a significantly narrower range of foods than children without autism." In other words, if you have an autistic child who eats poorly, you're not alone. Poor eating habits can lead to a wide range of nutritional problems which, in turn, can lead to problems ranging from health issues to attentional deficits to behavioral problems.

It turns out, though, that "poor eating habits" and "feeding issues" can fall into more than one category because they have several different causes and many levels of severity. Resolving problems with feeding, picky eating, food intolerances, and nutritional deficits can make a major positive difference in your child's life. Here are some of the ways in which feeding issues can impact your child, along with some suggestions for addressing the problem.

Feeding Issues Related to Sensory Challenges

Your child won't eat broccoli, apples, nuts, or breakfast cereals. Or he won't touch yogurt, milk, applesauce, soup, or oatmeal. In both of these cases, there's an obvious avoidance pattern: in the first case, the child is rejecting crunchy foods. In the second case, he won't tolerate smooth or gooey foods.

People with autism can be very sensory defensive, meaning they are easily upset by (and thus avoid) certain sensory experiences. They may hate bright lights or loud noise. They may also avoid strong smells and certain tactile experiences. Certain foods have strong smells and tastes; others have specific textures that may be appealing or disgusting to individual children.

There are a few simple fixes for eating problems related to sensory challenges:

  • Once you detect a pattern (nothing crunchy, for example), stop serving crunchy food. It's that easy. Cook the broccoli till it's mushy. Serve oatmeal instead of Rice Krispies. There's always a perfectly acceptable nutritional alternative to foods of any given texture, smell, or taste.
  • If you're determined that your child MUST eat certain types of food that he can't easily tolerate, consider "hiding" them in other foods. Many parents put veggies into delicious quick breads and muffins, for example.
  • At the same time as you're finding ways to accommodate your child's needs, consider finding a sensory integration therapist who has experience with feeding issues. She may be able to help you and your child learn to eat a wider range of foods.

Feeding Issues Related to Gastrointestinal Problems

According to one review of multiples studies, there is "a strong relationship and significant correlation between eating problems and gastrointestinal dysfunction [in children with autism]." This finding, while being very important, does not mean that GI problems actually cause autism. What it may mean, however, is that some of your child's more extreme behaviors may be related to pain and discomfort from gas, bloating, diarrhea, or acid reflux. Solve the underlying problem, relieve the pain, and your child may find it much easier to focus, think well, control his emotions, and behave more appropriately.

If your child is verbal and can describe her physical sensations, it should be easy to determine whether she is experiencing any GI issues. Other signs are diarrhea, constipation, flatulence, or a hard belly. You may also notice your child pressing her stomach up against pillows or chairs to relieve pressure. If you do believe your child is experiencing GI problems, you can take some important steps to address them:

  • Start by contacting your pediatrician and asking for a GI evaluation. If your pediatrician is skeptical, describe your child's symptoms and stick to your guns.
  • While you wait for an evaluation, start a journal to track your child's experience. When do the GI symptoms seem to start (after meals? between meals? at night?)? Which foods seem to trigger the symptoms? What behaviors do you believe are being triggered by GI pain or discomfort?
  • Some children with autism seem to have negative reactions to milk products (associated with a protein called casein) and/or wheat products (gluten). These reactions may not be allergies, but they can lead to very real symptoms. If you do believe your child is responding negatively to either milk or gluten, you can consider starting a gluten and/or casein-free diet. It is very important, though, to ensure your child is getting enough nutrition, so it's a good idea to work with your pediatrician or with a dietician.

Feeding Issues Related to Autistic Behavior Patterns

Like many children, kids with autism would usually prefer chicken nuggets and pizza to salads and fruit. Unlike many children, however, kids with autism can get absolutely stuck on very few food choices and absolutely refuse to make even the slightest change. If required to eat a carrot stick, an autistic child may melt down like a nuclear power plant!

While it is possible that these extreme preferences are sensory (see the section above), it's also possible that your child has developed a routine that is extremely difficult to change. People with autism, in general, prefer sameness and function well with routines, but sometimes a strong need for sameness can get in the way of proper nutrition.

If you're struggling with an autistic child's need to eat the same things, in the same order, day in and day out, start by checking to see if there is a real nutritional problem. If your child eats a limited but complete diet (only 2 or 3 proteins, carbohydrates, and fats) it may, in fact, be the case that he's not in nutritional trouble. If you're worried, you might just supplement his diet with a multi-vitamin. Next, rule out and/or address sensory or physiological problems (see the sections above).

Assuming that your child's diet is really poor, and you've already addressed any sensory or physical issues, you'll need to address the behavior. There are several approaches you can take, and you can mix and match:

  • Use a behavioral approach. Call it behavioral therapy or bribery, when you tell your child "eat a bite of spinach and I'll give you a prize," you may solve your child's eating problem. Bribery can work well, but it can also backfire. Be careful not to, for example, offer a toy for every bite of new food, as your child will become dependent on prompts and rewards.
  • Find foods that are similar to his favorites. If your child loves chicken nuggets, chances are good that he'll also enjoy chicken patties (a different shape). She may also be willing to try fish sticks (same shape and texture) or even chicken fried steak. Similarly, a child who likes applesauce may be willing to try apple slices or apple pie.
  • Offer options. For some children with and without autism, food is one of the few areas where they feel they exert control. Rather than getting into a power struggle, offer your child several food options and let him pick those he prefers. Some parents use muffin tins to offer a smorgasbord of small acceptable possibilities.
  • Write a social story. Social stories are short stories, sometimes with illustrations, that you can write specifically to prepare your child for something new. You might write, for example, "When it's dinner time, I sit at the table. There are different foods on my plate. I must eat one bite of every food."
  • Be sneaky. Sometimes it's possible to expand a child's horizons without his being actively aware that it's happening. For example, offering a whole wheat version of a favorite snack can up its nutritional value.

Resources and Research

A great deal of research has gone into the issue of autism and nutrition. Some is very helpful in guiding both families and doctors. It's important to note, however, that not all research is of equal quality, and some is conducted with a specific agenda in mind. For example, researchers may conduct studies in order to validate a product they want to sell or to convince parents that a particular perspective is correct.

Solid, replicated research studies have shown that:

  • Children with autism do, in fact, have more eating issues than other children.
  • Children with autism do, in fact, have more GI problems than other children. The reason for this has not yet been determined, though there are several theories.
  • Some children with autism are sensitive to specific foods such as casein, gluten, artificial sweeteners, and dyes (this is true of children without autism as well).
  • Some children with autism, probably because of picky eating habits, have nutritional deficits that can be addressed through supplements.
  • Some problematic behaviors are almost certainly increased by food/nutrition-related issues and can be alleviated through a variety of means including dietary changes and supplements.
  • Because people with autism are often anxious, and anxiety is often associated with eating disorders, it seems likely that people with autism are at risk of eating disorders such as anorexia and bulimia.

No solid, replicated research suggests that autism is caused by particular foods or can be cured through nutritional changes of any kind.

Screening for Feeding Issues

Nicole Withrow and Jennifer Franck developed a screening tool called the Sensory, Aberrant Mealtime Behavior Inventory for Eating (SAMIE), which they applied through a survey to a large group of children and teens with autism. The tool helps parents and practitioners to zero in on the specific challenges they need to address and provides some direction for action.

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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