An elimination diet can help a person identify foods that cause discomfort or symptoms of an allergic reaction.

In general, the diet should be short term and adopted under a healthcare professional’s supervision. There can be risks as well as benefits.

Below, learn about types of elimination diets, the steps involved, and possible benefits and risks.

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Up to 20% of the global population has a food sensitivity or intolerance. An elimination diet is one way to help identify the specific foods or ingredients responsible for the symptoms. Dietitians and allergy specialists may recommend it.

Some food groups and specific foods can also worsen symptoms of gastroesophageal reflux, migraine, autoimmune disorders, and irritable bowel syndrome (IBS), among other health issues, and a doctor may recommend an elimination diet for anyone who is unsure of their triggers.

The diet involves not eating several foods known to cause symptoms. Over time, a person resumes eating these foods, one by one, until they can determine whether any has caused or worsened their symptoms. They can then avoid these foods going forward.

Non-IgE-mediated reactions

This medical term refers to food allergies that do not cause an anaphylactic response. An anaphylactic response is a potentially life threatening allergic reaction. It is also known as an immunoglobulin E (IgE)-mediated reaction.

Non-IgE-mediated reactions are not life threatening, but they can still affect a person’s health.

If a person has a food allergy, their immune system reacts to certain foods as though they were harmful. These allergies affect 5% of children and 4% of adults in the United States.

Symptoms associated with non-IgE-mediated allergic reactions include:

If a person has any of these or other symptoms that are unrelated to a known medical condition, a doctor may recommend an elimination diet.

Learn more about food allergies here.

Food intolerances

Elimination diets can also help a person identify the foods responsible for intolerances. These issues are different from food allergies and do not involve the immune system. If a person has an intolerance, they may have difficulty digesting certain foods, and the process can cause discomfort. Intolerances affect 15–20% of the population.

Symptoms of a food intolerance may include:

Learn more about food intolerances here.

A healthcare professional can recommend which foods to eliminate and gradually reintroduce. Some people may only need to eliminate dairy or wheat, but other elimination diets can be more restrictive, including the:

  • Low FODMAP diet: This involves eliminating fermentable oligosaccharides, disaccharides, monosaccharides, and polyols from the diet, which requires a person to avoid many fruits, dairy products, and artificial sugars. This is a common approach to IBS treatment.
  • Few-foods diet: For someone with multiple food allergies or difficulty pinpointing specific allergens, a doctor may recommend following a few-foods elimination diet for only a few weeks.
  • Autoimmune protocol diet: This is also known as the AIP diet, and healthcare professionals mainly recommend it to treat autoimmune diseases.

Most elimination diets have a four-part structure:

  1. Planning. In a journal, a person records what they eat for 1–2 weeks and notes any symptoms. A healthcare professional reviews the journal, helps identify potential trigger foods, and discusses when to start the diet.
  2. Avoiding. The person avoids the potential triggers for 2–4 weeks, although the recommended timing can vary. It is important to check food labels carefully at this stage. If symptoms improve after eliminating several foods at once, a person can move on to the next step.
  3. Challenging. First, a person needs to be symptom-free for 5 days. Next, they can reintroduce an eliminated food back into their diet every 2–3 days. It is important to be very aware of whether any symptoms return during this stage.
  4. Maintenance. Using their observations from the previous stages, a person establishes which foods, if any, they should avoid going forward. The doctor or a dietitian can recommend ways to supplement the diet to prevent any nutritional deficiencies.

An elimination diet varies in length, and it is important to follow a healthcare professional’s guidance. Some people experience changes in their health as a result, and medical supervision is essential.

An elimination diet can help a person identify a food or food group that causes symptoms of a health issue. Beyond allergies and intolerances, these diets may help manage symptoms of:

Eliminating a food or food group may lead to a deficiency in key nutrients. However, careful planning, supplementation, and food substitutions can help. This is why it is important to receive medical guidance before, during, and after an elimination diet.

Another consideration is that restrictive diets can be very difficult to follow and may affect the quality of life.

A 2017 study found that parents of children on elimination diets for non-IgE-mediated food allergies gave lower quality of life scores for their kids, compared with parents of children with sickle cell disease or intestinal failure. The parents of the elimination diet group reported increased anxiety, feeding problems, and social isolation related to the diets. The more foods that were eliminated, the lower the reported quality of life.

Elimination diets can help a person identify any foods that may be contributing to allergies, intolerances, or symptoms of conditions such as IBS.

It is important to note the risk of nutritional deficiencies, however. Anyone considering this type of diet should receive medical advice.