One of the questions I’m asked most frequently is how to test for food sensitivities. Many of my clients (both kids and adults) experience physical as well as mental/emotional symptoms that they suspect may be linked to foods they’re eating. Of course, they want to know which foods might be triggering their symptoms.

Food sensitivities can cause a wide range of symptoms

These symptoms can range from digestive upset, to skin rashes, to brain fog. Research published in the distinguished scientific journal The Lancet shows that food sensitivities can even cause attention issues, hyperactivity, aggression, and impulse control difficulties. The full list of potential food sensitivity symptoms is quite astonishing. That’s why it’s important to be informed about the best way to test for food sensitivities.

Food sensitivity testing is widely available (but not very reliable)

Since DIY food sensitivity testing (i.e., direct-to-consumer testing kits you can use at home) is now widely available, interest in this kind of testing has increased exponentially. Unfortunately, these tests are not very reliable.

Food sensitivity tests measure Immunoglobulin G (IgG) antibodies, which we develop in response to certain foods. These antibodies are different from those associated with severe immune responses. Severe immune reactions are Immunoglobulin E or IgE reactions.

Food sensitivity tests measure markers that are part of our normal immune response

While food sensitivity tests measure IgG antibodies fairly reliably, the catch is that the presence of IgG antibodies does not necessarily indicate a sensitivity. IgG antibodies are part of our normal immune response. These antibodies are found in virtually all healthy individuals. As a result, IgG tests are not very accurate in identifying actual food sensitivities.

There is another option that is much more accurate and provides better insights

That is an elimination diet. A well-planned and carefully executed elimination diet is the “gold standard” for determining how a person reacts to different foods. Plus, it’s free!

How to test for food sensitivities using an elimination diet

For a period of about 3-4 weeks, you remove foods most likely to be irritating and inflammatory from your diet. These include highly processed foods, sugar, grains, and dairy. If your specific symptoms and health history warrant it, you might remove some additional inflammatory foods as well.

First, you eliminate foods, and then you slowly reintroduce them

After the elimination phase, you carefully reintroduce these foods one by one. As you reintroduce them, note how you feel. During the reintroduction phase, it’s important to reintroduce a single food for one day and eat at least two servings of it at different times. Monitor your symptoms for the next two days. Then, reintroduce the next food. At the end of the reintroduction phase, you should have a very good idea of which foods support your health and which don’t.

Your symptoms during elimination and reintroduction provide important clues

Symptoms to look for during elimination and reintroduction of foods include: insomnia, fatigue, joint pain, bloating, brain fog, skin breakouts or rashes, headaches, digestive and respiratory issues, and mood and behavior changes. If these symptoms improve during the elimination phase, and then reappear during the reintroduction phase, that’s a reliable indication of a food sensitivity.

It’s important to note that food sensitivity reactions are often mild to moderate. In addition, they can be delayed (up to 72 hours!) and can also last longer than classic allergic reactions. So even subtle symptoms that occur days after the reintroduction of a certain food can indicate a food sensitivity.

Preparation is the key to testing for food sensitivities with an elimination diet

Set yourself up for success for an elimination diet by preparing the week before. Preparation will generally include some meal planning, shopping for the right foods, and looking up recipes. Keep a journal during elimination and reintroduction to note symptoms and changes. This will make it easier to identify patterns related to consumption of certain foods.

Ultimately, the goal is to have the least restrictive diet possible. While eliminating one food in exchange for significant symptom relief might be manageable, people with multiple food sensitivities are in a much more difficult spot. An individualized nutritional support plan that includes probiotics, enzymes, and other gut-healing supplements can make a significant difference. In time, as the gut heals and symptoms improve, many people find that they’re able to tolerate foods that previously caused problems for them.

If you suspect that food sensitivities may be causing some of your symptoms, and you’d like to do an elimination diet with the support of a nutritionist, I’d love to connect with you! Visit my Work With Me page to learn more and set up a consult!