What Are Food Sensitivities?

Meal with food like noodles and spicy peppers that people may be sensitive to.

Food Sensitivities: What They Are And What You Can Do About Them

Food sensitivities are a real thing and impact many people. From nut and dairy allergies to gluten intolerance and soy based issues, we see guests at the fitness retreat each week who are seeking answers and relief. Food sensitivities can show up in the form of an actual allergy to an intolerance and can produce a whole host of symptoms. We’ll cover allergies and intolerances in this blog post as, a list of symptoms and a few strategies that can help identify if you might be suffering from some type of food based issue.

Understanding The Immune System

To first address food sensitivities, we must delve into the immune system so you have an idea as to why these nutrition issues might be affecting you. One of the fundamental components of our immune system is the ability to recognize what is “us” and “not-us” by “reading” the chemical signatures of all substances within our bodies.

Our innate immune system is an ancient type of immune system that almost all multi-cellular organisms share. One of the key pieces of our adaptive immune system is simple: a physical barrier between foreign materials and us. These barriers are choosy about what which nutrients they let in and they have secondary barriers to help aid in that process. A few of those secondary helpers are:

  • Saliva - washes away pathogens that might adhere in the mouth.

  • Stomach acid - kills many pathogens.

  • Mucus - traps pathogens and carries them out of the body.

  • Good gut bacteria - colonize the GI tract.

Any pathogens that bypass the first line of defense are identified by the innate immune system, targeted, killed, and disposed of. This process also involves inflammation. As part of identifying the invaders, the innate immune system also signals and calls in reinforcements: the adaptive immune system.

Our adaptive immune system is a more sophisticated form of defense. It distinguishes “self” from “not-self” and responds to non-self antigens (literally, antibody-generators) that bypass the innate immune system. The adaptive immune system’s helper agents are:

  • B cells

  • T cells

When the adaptive immune system detects an antigen, it not only locks on to that antigen, but remembers it for next time.

In general, these immune systems function very well together as a way of killing what we don’t want or might harm us. However, in people with allergies and other sensitivities, the immune system is often hyper-reactive — it sees otherwise harmless things as threats, and responds accordingly. This is where many food based allergies and intolerances come from.


With food allergies, the immune system produces Immunoglobulin E (IgE) antibodies to particular substances (think a substance within an actual food). When the allergic person meets the food, the body recognizes it as a pathogen. This stimulates the release of histamine and other chemicals.

Histamine creates the many of the obvious symptoms like swelling and inflammation in responsive tissues (e.g. in respiratory passages, face/eyes, skin rashes or hives, etc.), along with other symptoms aimed at rejecting the pathogen, such as vomiting or diarrhea. It can also create cardiac events. It’s serious. Most people experiencing this type of a food allergy response will know it.


  • Tree nuts

  • Peanuts

  • Dairy

  • Eggs

  • Soy

  • Wheat

  • Shellfish

  • Fish

With histamine, there can also be an intolerance. This equates to an intolerance to histamine containing foods. Examples would include intolerances to specific foods within a category such as these:

  • Certain types of fish but not all fish - tuna, sardines or herring

  • Only specific types of cheeses

  • Certain vegetables like spinach, avocado or eggplant

  • Processed meats

  • Fermented foods including wine, beer and some vinegars

  • Chocolate, coffee and tea

  • Certain fruits such as strawberry, tomato, kiwi, pineapple and stone fruit


Some types of food sensitivities, for example, are immune-based responses but a T-cell response instead of an IgE response. Other food intolerances can come from inadequate digestive enzymes, such as not having enough lactase to break down lactose, the predominant sugar in milk. Food tolerances and sensitivities can change over time and with other environmental factors, such as stress.


While food allergies are usually pretty clear-cut, food sensitivities are harder to diagnose. They may show up in some of the forms below.

  • Fatigue and pain

  • GI symptoms

  • Skin problems like acne, rash or itchiness

  • Local inflammation like joint inflammation

  • Brain fog, mood issues or sleep problems

  • Stuffy nose or post nasal drip

*While these symptoms can point to food intolerances, they could also be symptoms of other issues.


There are two ways to determine food allergies and sensitivities.


As stated above, food allergies are pretty straight forward and produce profound symptoms that are hard to miss. If you are experiencing symptoms and haven’t visited with a nutritionist or allergist, I would highly recommend it as soon as possible. With food sensitivities, there are actual tests that can be done through your local nutritionist or by companies like Everly Well where you can send in an at home food sensitivity test for diagnosis.


The other way to diagnose such issues would be to journal what you eat and how you feel afterwards. Believe it or not, your mood, digestion and other indicators can be great information in determining your food based sensitivities. Our Balanced Eating Journal is a great tool to help you determine which foods are working for you and which aren’t. Here’s what to include in your journal:

  • Time you ate

  • What you ate - include everything

  • What you notices after you ate - examples:

    • I didn’t feel anything

    • Stuffy nose after about an hour.

    • My stomach was upset or I experienced pain and discomfort

    • My skin was itchy

Journal a few days worth of food and take a look back to see which meals containing certain foods are producing these unwanted symptoms. From there, you can begin to understand what’s working for you and what isn’t.


While food sensitivities may not be quite as severe as food allergies, they all produce an unwanted immune response in the body that needs to be addressed. Think about it this way, if your body is constantly working hard to fight off the foods that it sees as an invaders, it can’t focus on recovery, repair and other important processes that it needs to focus on. It’s important to identify which foods aren’t working for you and eliminate them so you can function at your healthiest, happiest self.

If you need help with journaling and figuring out your food sensitivities, join us for a fitness retreat or check out our nutrition coaching to get professional guidance. I hope this post helps you with identifying your food based issues so you can move forward with a plan of action and feel your best. If you have any questions or comments, please leave them in the comment section below. - Margot & Team


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A picture of foods that could cause sensitivities.