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Is Your Food Making You Sick?

Using elimination diets to discover food sensitivities and intolerances


Updated July 07, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

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

An elimination diet, sometimes called an exclusion diet, is a tool used by doctors 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 being such a large part of the treatment of food allergies and sensitivities, there have not been many studies to see if they work. A 2010 Cochrane review of nine studies found that elimination diets by themselves, without the benefit of allergy testing, did not improve symptoms for people with eczema. One study found that babies with eczema who had a positive egg allergy test did improve on egg-free diets.

There is some evidence that long-term elimination diets may actually increase your body’s allergic response to a food. A study done at Johns Hopkins University found that children who had outgrown peanut allergies but who continued to eliminate peanut from their diets had a recurrence of severe allergies.

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 under the supervision of a doctor.

Step-by-step elimination diet instructions

  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 the possibility of 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 gluten 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

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 – “stew” will not be as helpful as “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

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 and celiac disease now have non-invasive tests that can be done in a lab.

Sometimes testing may be inconclusive and 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.

Few foods diets or detox diets

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 in 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 doctor’s office.


Fleischer DM, et al. Peanut allergy: recurrence and its management. J Allergy Clin Immunol. 2004 Nov;114(5):1195-201.

Bath-Hextall FJ, Delamere FM, Williams HC. Dietary exclusions for established atopic eczema. The Cochrane Database of Systematic Reviews 2010 Issue 10

Fleischer DM, et al. Oral Food Challenges in Children with a Diagnosis of Food Allergy. J Pediatr. 2010 Oct 27.

Jennifer J. Schneider Chafen; Sydne J. Newberry; Marc A. Riedl; et al. Diagnosing and Managing Common Food Allergies: A Systematic Review. JAMA. 2010;303(18):1848-1856

  1. About.com
  2. Health
  3. Food Allergies
  4. Diagnosing Food Allergies
  5. Elimination Diets (Is Your Food Making You Sick?)

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