How to Try an Allergy Elimination Diet

If you suffer from chronic diarrhea, constipation, abdominal pain, or gassiness, an elimination diet may help you determine if your symptoms are caused by particular food sensitivities.

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Here's how to safely and effectively use elimination diets, along with food diaries and new medical tests, to eliminate the pain in your gut.

Elimination Diets: Confirming Allergy Testing

An elimination diet, sometimes called an exclusion diet, is a tool used by healthcare providers to confirm the results of allergy testing. Elimination diets are also a popular alternative medicine treatment for conditions that range from arthritis to irritable bowel syndrome.

Despite elimination diets representing such a large part of treating food allergies and sensitivities, there have not been many studies to see if those elimination diets actually work. In studies that have been performed, the results have been mixed.

For example, a review of nine studies found that elimination diets by themselves, without the benefit of allergy testing, did not improve symptoms for people with eczema. However, another study found that babies with eczema who had a positive egg allergy test did improve on egg-free diets.

Meanwhile, researchers have found that elimination diets driven by the results of allergy testing may be useful in the condition eosinophilic esophagitis, which can cause damage to your esophagus and symptoms like heartburn and trouble swallowing. Similarly, elimination diets following allergy testing have helped curb symptoms of irritable bowel syndrome and migraine.

Reactions Could Get Worse Long-Term

There is some evidence that long-term elimination diets may actually increase your body’s allergic response to a food. If your allergic response had been relatively minor prior to your elimination diet, this may not be a welcome development (and it could, in some cases, be dangerous).

For example, a study done at Johns Hopkins University found that children who had outgrown their peanut allergies but who continued to eliminate peanuts and peanut products from their diets had a recurrence of severe allergies. In addition, people who eliminate the protein gluten from their diets often find their reactions get much worse when they do inadvertently consume foods that contain gluten.

A note of caution: If you have symptoms of classic food allergies, such as hives, swelling of lips and tongue, or anaphylaxis, any re-introduction of foods into your diet should be done only when supervised by a healthcare provider.

How to Use an Elimination diet

Here are step-by-step elimination diet instructions you can follow (consult with your practitioner first):

  1. Completely eliminate the food from your diet for two weeks. While you are doing this, eat simple foods that you prepare yourself, to avoid possible cross-contamination. For example, if you are eliminating soy, eat fresh fruits, veggies, and meats rather than anything that comes in a package or is prepared in a restaurant, unless it has been made in a certified soy-free facility.
  2. Keep track of your symptoms to see if they improve. If they don’t improve, then the food you eliminated was most likely not the problem.
  3. If they do improve, re-introduce the food in its most basic form to see if you have a reaction. This is called a “challenge.” In the case of soy, a good challenge would be a soybean, rather than soy sauce or a food with multiple ingredients. Some people with celiac disease are so sensitive to gluten that they may react to microscopic gluten traces that could be present due to cross-contamination on the outside of a vegetable, or in a product that is labeled gluten-free.
  4. If your symptoms get worse after eating the food, try the process of elimination and challenge again to confirm the results. It is possible that the first time was a coincidence. For example, perhaps the food you used for your challenge is greasy and upset your stomach, but you can tolerate the food in another form.

Food Diary Uses

A food diary can help make your elimination diet more accurate and successful. Keeping track of the food you eat and your symptoms allows you to look for patterns. It can also help identify possible sources of cross-contamination, or other foods that may be contributing to your symptoms.

How to keep a food diary:

  1. Keep a small notebook in which you record everything you eat at each meal. Try to write down the major ingredients of the food you eat. For example, writing down “stew” will not be as helpful as making a note of “strew made with beef, potatoes, carrots, rosemary, and garlic.”
  2. Throughout the day, record your symptoms. Did you have diarrhea? Coughing? Runny nose? At what time did your symptoms occur? Did they occur immediately after eating, or were they delayed? How severe were they? If you have symptoms of classic food allergy, now would be a good time to find a great allergist.
  3. After a few weeks, look for a pattern of foods and symptoms. It may take a month or more before you are able to see a pattern. It may be impossible to see a pattern in your symptoms if you are reacting to a food you eat every day. For example, if you eat a sandwich on wheat bread every day at lunch, you may not see a variation in your symptoms from day to day, even if the wheat on your sandwich is making you sick.

Medical Testing Assistance

You may not think your symptoms are severe enough to warrant medical testing, but testing can help you to target foods for your elimination diet, or even remove the need for you to go through the process.

Lactose intolerance now has a non-invasive test that can be done in a lab, and you can screen for celiac disease with blood tests (although you'd still need an endoscopy to confirm your celiac disease diagnosis).

Sometimes testing may be inconclusive and will require an elimination diet to follow up on the results. It is possible to have a positive allergy test result for a food but not have an allergic reaction to that food. Allergists generally recommend that people who have not had severe allergic reactions to a food eliminate it from their diet and do a food challenge in their offices.

Medical testing can also determine if your symptoms are caused by something other than food sensitivity. Gall stones can cause diarrhea and abdominal pain when you eat greasy food, which may be seem to be lactose intolerance if the greasy food in question was a cheesy pizza. A gastroenterologist can help to put the pieces of the puzzle together and figure out the cause of your pain.

A Word From Verywell

Some alternative medicine practitioners will recommend fasting for long periods of time or eating diets made up of only a few foods as a method of determining food sensitivities. Some diets are limited to foods that a particular diet considers “non-allergenic,” even though it is possible to be allergic to just about any food. Others limit you to one or two food groups—just fruits and vegetables, for example.

Use caution when eliminating foods from your diet. Reducing the number of foods you eat can lead to poor nutrition, especially for children.

Some people may avoid food that they can actually tolerate. A study done at National Jewish Health found that children with diagnosed food allergies were able to eat 84% of the foods they had eliminated from their diets after trying the foods in the practitioner’s office. Therefore, before you eliminate a food from your diet or from your child's diet, make sure to discuss it with your healthcare provider.

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.

By Jeanette Bradley
Jeanette Bradley is a noted food allergy advocate and author of the cookbook, "Food Allergy Kitchen Wizardry: 125 Recipes for People with Allergies"