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How Food Allergies and Sensitivity Affects Athletes

By Katie Rhodes | March 26, 2019, 2:42 p.m. (ET)

Food allergies

Reported food sensitivities and food allergies have been on the rise. This can be due to a combination of environmental factors and more awareness of the signs, symptoms and treatment plans.

Given the popularity, there is a lot of confusion on what exactly defines a food allergy versus what defines a food sensitivity, or food intolerance, and how to approach the issue if you suspect you or a loved one may be experiencing the symptoms. 

Although this affects the entire population, I will focus on how it can specifically affect athletes. 

What Is a Food Allergy? 

A food allergy triggers an immune system response. Upon ingesting the protein in the food allergen, your body recognizes this protein as a foreign body it must fight to eliminate. Your body then produces antibodies that learn to detect this invader, therefore triggering physical responses when the food is ingested again. To your body this food is now a poison. A food allergy can be life threatening, while a food sensitivity is not.

Common allergic reactions include hives, swelling, rash, digestive issues, dizziness, and anaphylactic shock. In some cases, when an anaphylactic reaction is not subdued by an epipen (epinephrine injection) or medical assistance, an allergic reaction can lead to death.  There are eight common food allergies: milk, egg, fish, shellfish, peanuts, tree nuts, wheat and soy. Sometimes cooking or processing the food can destroy the protein causing the reaction, mostly seen in cooked egg and milk. This is dependent on the severity of the individual’s allergy. 

Diagnosing: If you are allergic to a food, the reaction occurs normally within the first hour of ingestion. Diagnosing a food allergy is done within a medical setting. Contact your local allergy clinic and they will do a full panel test, usually skin prick testing and blood testing. If you suspect you have an allergy due to physical symptoms, NOT including speculation only due to a blood test, remove the food from your diet until your appointment. 

What is Food Sensitivity? 

Food sensitivity normally triggers an unpleasant digestive system response and is not life threatening. A food sensitivity can be caused by many things. Common causes are physical reactions to certain foods, food additives, pharmaceuticals, chemicals and certain sugars naturally occurring in foods. Digestive reactions include but are not limited to diarrhea, constipation, reflux, gas, bloating, abdominal cramps and nausea. Some non-digestive system reactions include runny nose, rash, fatigue and headaches. The number of food sensitivities is ever growing, but some common food sensitivities include MSG, sulfites, artificial colors, gluten, dairy, caffeine, salicylates and fructose. 

Diagnosing: Since most athletes deal with food sensitivity, I will spend more time on diagnosing and treating the issue. Diagnosing a food sensitivity can be extremely difficult since symptoms can arise up to 48 hours after ingestion and can last days and sometimes weeks after ingestion. Pay attention to physical symptoms and journal any symptom that seems to be recurring along with your specific daily intake. After a few weeks of this I recommend taking out the food or foods you suspect may be the culprit. Add one food at a time back into your diet five to seven days apart. Continue to journal and you are more than likely able to pinpoint the food or foods. Visiting an allergy clinic with your journals is not a bad plan of action if you would like an expert opinion, usually dependent on the severity of symptoms or how much of an impact it is having on your physical performance. Hear me when I say, do not just jump to getting a blood test done that lists pages and pages of your food sensitivities. This can be inaccurate and actually dangerous if you remove the food and then add it back into your diet. If the symptoms are not life threatening, take this blood test and your journals to the allergy clinic appointment and they will help you determine what you should remove and make a plan of action you are comfortable with. Blood tests simply aren’t 100% accurate. 

You have a food allergy or sensitivity, now what? 

If the food or foods you are removing contribute significantly to your nutritional needs, it is important to replace what is now lost through consuming another food or supplement that provides those needs. This is especially important for athletes since you rely heavily on an adequate diet to help you perform, recover and train. The most common foods that need to be supplemented if removed include milk products and wheat. Replace milk products with other high calcium foods such as salmon, sardines, seeds, nuts, soy products, beans, lentils, dark green leafy vegetables, rhubarb, and fortified foods such as some cereals, flour and orange juice. Replace wheat products with other grains such as rice, oat, quinoa, millet, buckwheat, amaranth, and corn. Wheat contains gluten, so is “gluten free” a wheat free product? NO. Although something is “gluten free”, it may still contain wheat. Be sure to make it a habit to read the nutrition label to determine if a product contains your allergen or sensitivity. Nutrition labels can change without notice, so just maintain that habit. Your body will thank you! 

What About Celiac Disease (gluten sensitivity)? 

Let’s have a laugh here. There are three kids of people in this world: those who do not avoid gluten, those who are diagnosed with celiac disease or suspect they have a legit reaction to gluten, and those who do it to be hip, trendy or think it will help them lose a few pounds. I write this laughing because so many people this gluten is the enemy and it simply is not. Consult with your allergist to determine if you indeed need to eliminate gluten from your diet. 

Food Sensitivity and Race Day

This stance arose from years of experience playing with athletes’ diets surrounding race day. If a client of mine has gastrointestinal issues on or days leading up to race day, I usually eliminate non-baked milk products (yogurt, cheese, milk, butter) and wheat products (bread and pastas) 48 hours before race day. Why? From my experience these foods are usually the culprit of some loose stool when you are already nervous about a race and you are more than likely traveling, making your food choices different than what your body is used to digesting. By eliminating, or limiting, these two groups you are steering more clear of products that could cause an upset tummy. But isn’t wheat important for carbohydrate loading? Wheat isn’t the only food that contains carbohydrates. I replace wheat with carbohydrates that are easy to digest like potatoes, white rice and bananas. 

Katie Rhodes, MS, RD, CSSD, LD, owner of OWN-Nutrition, is a registered and licensed dietitian in Little Rock, Arkansas, with a Master of Science in clinical nutrition. Through her experiences training elite athletes and working in the clinical setting at Arkansas Children's Hospital and the Central Arkansas Veterans Association, Rhodes understands that what we are putting in our bodies directly affects our performance, quality of life and longevity. She's worked with triathletes for eight years on their nutrition year round as well as focusing on race day nutrition. Rhodes primarily works with clients remotely, through phone calls and Skype for communication, to supplement unique, personalized nutrition plans. 


The views expressed in this article are recommended for athletes who are familiar with metabolic efficiency principles. As always, only introduce new fueling strategies in training and adopt only what works for you. The views are the opinion of the author and not necessarily the practices of USA Triathlon. Before starting any new diet or exercise program, you should check with your physician and/or coach.