Food Sensitivities: Could Your Fitness Clients Benefit from a Food Sensitivity Test?

Food Sensitivities Featured

Diet and exercise are both highly personal practices; individuals can have food sensitivities that remain undetected unless intentionally examined. This means your clients could be making all the “right” healthy choices but have sensitivities to the foods they are consuming. If you have a client who sees a halt in their progress or who consistently experiences certain, marked symptoms, it might be worth asking if they’ve considered testing for food sensitives and/or allergies.

Food Sensitivities vs. Allergies

The primary difference between a sensitivity and an allergy is the way the body responds when a food is consumed. A food sensitivity refers to the inability to digest and process a given food item and consumption of a trigger food results in non-life threatening but uncomfortable symptoms. Allergies, in contrast, trigger a more dramatic immune response and are often more severe than a food sensitivity (Harvard Health ).

Symptoms of Food Sensitivities

While reactions related to food sensitivities are not likely dangerous, they are certainly disruptive. Some common symptoms associated with food sensitivities include bloating, gas, joint pain, stomach pain and general gastrointestinal distress, fatigue, difficulty losing weight, rashes, cognitive disruption or fog, headaches or migraines, depression, and anxiety. Some individuals experience a cluster of symptoms depending on if their sensitivity is high, moderate, or low (Everlywell; Harvard Health ).

Common Trigger Foods

Sensitivities to foods – even healthy options – are common. Some of the most common offenders include eggs, soy, corn, dairy products, shellfish, foods high in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP), gluten-containing products, food additives, and meat coming from animals raised on corn and soy (Everlywell).

Testing and Diagnosing

It’s obvious not within a fitness professional’s scope of practice to recommend any specific test or diagnose someone with any condition. It is, however, within your scope to have the conversation with your clients if they seem to be experiencing odd reactions to foods that are, by nature, intended to be healthy and supportive. If they are experiencing symptoms, you might encourage them to speak to their primary care physician or a registered dietitian about their options.

A food sensitivity test is generally done through a finger-prick blood test and the IgG (Immunoglobin G) response level is measured and foods are commonly categorized as “high reactive”, “moderately reactive”, and “low reactive”.

Personal Testimonial

After the birth of my first child, I observed strange reactions to foods I normally consumed – eggs, Greek yogurt, oatmeal, bananas, and chicken. Early on, I dismissed it assuming I was still in a recovery phase after giving birth. The longer it went on, the more evident it became that something was amiss.

Eventually, I decided to examine what I was eating and determine if foods I was consuming, although healthy and balanced, were simply no longer in agreement with my system. I was tested for both allergies and sensitivities and discovered no allergies but 19 food sensitivities that were causing physical issues for me. I eliminated my trigger foods and symptoms disappeared. Thankful and relieved, I reimagined my daily plate and have had great success since putting my daily intake under a microscope.

Next Steps

It’s likely you are already having detailed conversations with your clients about their daily dietary habits, so it’s an easy segue to ask about potential food sensitivities if clients note specific symptoms that haven’t been explained up to that point. It is also a good idea for you to become versed in food sensitivities by diving into different learning opportunities that discuss this topic. If you have a registered dietitian in your network, ask them to help you deepen your understanding so that you are better prepared to have the conversation should it arise.


Dr. Erin Nitschke, NFPT-CPT, NSCA-CPT, ACE Health Coach, Fitness Nutrition Specialist, Therapeutic Exercise Specialist, and Pn1 is a health and human performance college professor, fitness blogger, mother, and passionate fitness professional. She has over 15 years of experience in the fitness industry and college instruction. Erin believes in the power of a holistic approach to healthy living. She loves encouraging her clients and students to develop body harmony by teaching focused skill development and lifestyle balance. Erin is also the Director of Educational Partnerships & Programs for the NFPT. Erin is an editorial author for ACE, IDEA, The Sheridan Press, and the Casper Star Tribune. Visit her personal blog at
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