Are At-Home Food Sensitivity Tests Worth It?

Athletes and food sensitivity

Picture this: Your training volume increases. Suddenly, you start feeling tired and you aren’t sleeping well. You start to notice you’re feeling gassy & bloated often, maybe even your bathroom schedule is off. You begin to think the food you are eating is causing the issue, because every time you eat, you have problems. 

So, you Google your symptoms because you have no idea what is causing these issues. Google said to try cutting a bunch of food out of your diet, so you do. This creates an even bigger problem, because you are limiting the nutrients or resources available to help your body function, let alone train. You’re feeling frustrated. So, you finally decide to get that at-home food sensitivity test that’s been coming up on social media, and now you’re left with 10 foods to eat, continuing to compound the issue. Not only do you NOT feel good, but you’re stressed and fearful to eat. 

This is all too common with athletes we’ve worked with, and honestly, we get it. When you are having GI symptoms, it is a frustrating and uncomfortable situation. And, there is a lot of chatter out there about what could be triggering you. GI symptoms aren’t always related to a specific food or food group. In fact, most times we work on these issues with clients, it’s related to chronic under-eating (intentionally via dieting or unintentionally due to an increase in training and not increasing food appropriately) and/or other stressors or infections. So, before you spend your hard earned cash on an at-home food sensitivity test, keep reading …

A quick Google search of GI symptoms will likely tell you to avoid a lot of different foods that ultimately are helpful to active bodies, rather than harmful.

Food sensitivity or intolerance vs. food allergy … let’s break it down:

It is important to distinguish between what a food sensitivity or intolerance is versus an allergy. Food allergy usually leads to the most severe reaction, known as anaphylaxis. This is a medical emergency where an allergen (typically a food) causes the body to react with an overboard immune response similar to shock. During anaphylactic reactions, blood pressure drops, airways narrow blocking breathing, the pulse becomes rapid and weak, and skin rash, nausea and vomiting can occur. (Mayo Foundation, 2021) On the other hand, a sensitivity or intolerance refers to the body’s inability to process or digest certain foods. This can cause a mild immune reaction and potentially lead to a wide range of symptoms.

According to the Academy of Nutrition and Dietetics, “food intolerances are not an immune system reaction. They relate to trouble digesting foods. Food intolerances can occur due to the lack of an enzyme needed to digest certain foods or, sometimes, as a reaction to additives or naturally occurring compounds in foods. Individuals with food intolerances may be able to eat small amounts of bothersome foods. But, when they have too much, their body reacts.” (Academy of Nutrition and Dietetics, 2023)

However, food reactions aren’t the ONLY thing that can cause GI symptoms. High stress, inadequate fiber intake, little variation in diet, and not eating enough can throw off your gut. Also, moderate exercise is beneficial to gut health, but prolonged exercise (think long training days, double workouts, training for long-distance endurance events) can affect intestinal permeability, meaning things get past the gut barrier that shouldn’t, resulting in digestive symptoms.

Are at-home food sensitivity tests worth it?

Food sensitivity tests are becoming more and more popular. With the evolution of at-home testing options, these tests are becoming increasingly available to curious consumers. The bigger question is, are food sensitivity tests worth it? And more importantly, are they even legit? 

Companies like Everlywell, Check My Body Health, Cerascreen and York Test all utilize differing methods, from saliva to blood from a skin prick, a hair sample or a breath test. These methods are intended to analyze two immunoglobulins, which are a type of protein called an antibody, which plays a role in the allergic response. The two immunoglobulins frequently examined by at-home food sensitivity tests include immunoglobulin E (IgE) and immunoglobulin G (IgG) to determine if elevated antibodies are present. Everlywell is probably the most comprehensive and available of all the at-home tests, and examines the IgG response to “96 common foods”. (Everlywell, 2023) 

Of interest, even Everlywell recommends following up with a clinician and implementing some form of an elimination diet, because you cannot determine an allergen or intolerance through testing alone. While IgE immunoglobulins do typically indicate an immune (allergy) response, IgG antibodies have not been shown to reliably identify either food allergies or sensitivities. Most people produce IgG antibodies after eating food. They are not specific to a person’s sensitivity, although past or frequent exposure to a food may cause these levels to be higher. (, 2019)

Put simply, if you eat a food frequently, there’s a very high likelihood that you will test as having a reaction (i.e. sensitivity) to that food.

There is an increasing body of research that seeks to examine the validity and reliability of these tests. Unfortunately, while the idea and convenience of an at-home test is exciting for those of us who love to know our internal metrics and track everything from our training to our sleep, the data currently does not support the claims made by at-home food sensitivity tests. (Gocki, 2016) In fact, the practice of using immunoglobulins as a method for assessing food sensitivity has been around since the late 1980’s to early 1990’s. However, despite the long duration of this method for investigating serum response to foods, research has not borne out valid proof of their effectiveness. (Teuber, 2007) In fact, it has done quite the opposite.

Far from empowering you with information, these tests may in fact result in a dangerous under fueling scenario, while creating macro- and micro-nutrient deficiencies that can exacerbate symptoms and negatively impact your training. In fact, according to PubMed (a highly respected database from the National Institutes of Health), the European Academy of Allergy and Clinical Immunology (EAACI) and Canadian Society of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma & Immunology (AAAAI) both advise against the use of at-home food sensitivity kits as a diagnostic tool. (Bock, 2010; Carr 2012)

Based upon the vast majority of research data, at-home sensitivity tests cannot provide clinical diagnosis. Though the companies that sell these tests will boast of testing that confirms evidence of their effectiveness, the consensus among third party peer-reviewed research articles is that these tests do not reliably or accurately indicate sensitivity. (Gocki, 2008; Stapel, 2016)

The major concern for these tests is that consumers will use them to unnecessarily eliminate foods, develop food anxiety or disordered eating, or potentially include foods that are dangerous to them. These tests may provide insight into possible food triggers, but are not definitive and require clinical follow up with a professional who understands the energy demands of your sport and potential other reasons for food intolerances. These tests may be useful to gain awareness for the curious, but clinical follow up of symptomatic suspected food intolerance is absolutely necessary for assessment and a care plan, to avoid excess dietary restriction. If you are suspicious that you may have a food related intolerance, you should make an appointment with your healthcare provider. Keeping a food journal, and making note of when you experience symptoms, correlated with what you have eaten may be a more beneficial way of identifying any potential triggers, and is much more cost effective than an at-home test. 

Recommendations from a Registered Dietitian

If you are currently experiencing gastrointestinal issues, be sure to:

  • eat enough fiber- we recommend that women should try to eat at least 21 to 25 grams of fiber a day, while men should aim for 30 to 38 grams a day) (, 2018)
  • consume adequate nutrient variety 
  • eat enough food
  • regulate your nervous system with mindfulness and breathing techniques
  • work with a coach who “gets it” and isn’t creating an over-training situation. 

If all of these things are going great for you, and you still have issues, it might be time to talk to your doctor and investigate what’s got your guts in a twist. 

Should you work with a Registered Dietitian for GI issues?

“Appropriate implementation and education about avoidance of food triggers is required across any food intolerance (and allergy). Patients attempting to modify their diet benefit from guidance by a dietitian, likely due to improved understanding and compliance, resulting in greater symptom response. The role of the dietitian is important not only during the initial stages of establishing the dietary modification whereby the dietitian can modify the level of restriction required based on the clinical picture; but is also integral in the implementation and interpretation of re-challenges to assess tolerance to specific food triggers. Appropriate education also ensures patients do not over-restrict their diet unnecessarily or undertake ‘diet-stacking’ in which they accumulate multiple dietary restrictions resulting in worsened food variety and nutritional adequacy”. (Tuck, 2019)

Working with a Registered Dietitian who understands your sport throughout the process of identifying and addressing any GI discomfort, whether it is food related or otherwise, can help you to develop a plan of action that takes into consideration any new medical diagnoses related to food allergies or intolerances, as well as personal preference for foods and training goals. 

If you are looking for an even more in depth look at gut health, look no further than our most recent masterclass. Here we will break down some of the most common buzzwords that pertain to gut health, and what it means to use nutrition to support your gut health. 

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Are food sensitivity tests accurate? Academy of Nutrition and Dietetics. (n.d.). Retrieved from 

Bock, S. A. (2010). Aaaai support of the EAACI position paper on igg4. Journal of Allergy and Clinical Immunology, 125(6), 1410. 

Carr, S., Chan, E., Lavine, E., & Moote, W. (2012). CSACI position statement on the testing of food-specific IGG. Allergy, Asthma & Clinical Immunology, 8(1). 

Everlywell. (n.d.). Why test IGG for food sensitivity? Everlywell Knowledge Base. Retrieved from 

Gocki, J., & Bartuzi, Z. (2016). Role of immunoglobulin G antibodies in diagnosis of food allergy. Advances in Dermatology and Allergology, 4, 253–256. 

Mayo Foundation for Medical Education and Research. (2021, October 2). Anaphylaxis. Mayo Clinic. Retrieved from 

Read “dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids” at Summary Tables, Dietary Reference Intakes | Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids |The National Academies Press. (n.d.). Retrieved January 19, 2023, from 

Stapel, S. O., Asero, R., Ballmer-Weber, B. K., Knol, E. F., Strobel, S., Vieths, S., & Kleine-Tebbe, J. (2008). Testing for igg4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report*. Allergy, 63(7), 793–796. 

Teuber, S. S., & Beyer, K. (2007). IGG to foods: A test not ready for prime time. Current Opinion in Allergy & Clinical Immunology, 7(3), 257–258. 

Tuck, C. J., Biesiekierski, J. R., Schmid-Grendelmeier, P., & Pohl, D. (2019). Food intolerances. Nutrients, 11(7), 1684. 

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