Food Intolerances

Have you experienced symptoms such as brain fog, fatigue, unusual bloating, or indigestion after eating certain foods? If these symptoms consistently occur after eating the same foods you may have a food intolerance. It is estimated that between 2–20% of people worldwide may suffer from a food intolerance (M) so you are not alone.

Something important to determine, first, is whether you’re experiencing a food intolerance or a food allergy. So what’s the difference?

  • Food allergy symptoms include hives, a swollen throat, and itching or tingling of the lips. Food allergies can be life-threatening so stay away from the problem food and visit an allergist to get tested ASAP (Winderl).
  • Food intolerance response takes place in the digestive system. It occurs when you are unable to properly breakdown the food. Symptoms include nausea, stomach pains, excessive gas, and fatigue (Pongdee).

If you’re wanting to determine if you have a food intolerance yourself before consulting a doctor it is highly suggested trying an elimination diet. An elimination diet is exactly what it sounds like. It is a two step diet in which you slowly eliminate foods that may be causing food intolerance symptoms. Here’s how to start;

1. Track Everything You Eat

To start you’ll need to know exactly what you are eating. While it may seem tedious at first, it will ultimately help you narrow down what is causing the symptoms. When tracking your foods you can either download an app, such as MyFitnessPal, to digitally log your food or keep a food journal to write down what you eat. Along with logging your food, it is important to also include how you are feeling after you eat. Being slightly bloated after eating a meal is usually normal; feeling nauseous, gassy and uncomfortable isn’t. One thing to remember when logging your food is to check the added ingredients as well.

Some of the most common food intolerances include:

  • Dairy
  • Gluten
  • Caffeine
  • Salicylates- found in a wide range of foods but often used as a preservative (Kubala)
  • Amines- produced by bacteria during food storage and fermentation and found in a wide variety of foods.
  • FODMAPS-a group of short-chain carbohydrates found naturally in many foods that can cause digestive distress.
  • Sulfites-used a preservative
  • Fructose

2. Start Eliminating

Once you’ve determined what foods you feel you are reacting to, stop eating them! It is best to eliminate these foods for 2-3 weeks since certain sensitivities can be delayed and are not immediate. A simple way to do this is picking foods you know you do not react to and making them the base of your diet.

Some tips that will help during this process;

  • Eliminating common allergy foods such as milk, eggs, nuts, wheat, shellfish, and soy if your food log did not narrow your foods down enough.
  • Staying hydrated. As your body gets rid of inflammation it will also get rid of water (Winderl)
  • Make sure you eat other foods that provide the same nutrients as the food you are eliminating from your diet (Robinson)

If your symptoms remain after removing foods you thought you were reacting to it is best to notify your doctor.

3. Reintroduction Phase

Once you’ve successfully followed your elimination diet for 2-3 weeks you can start reintroducing certain foods you eliminated. The point of this is to determine exactly what foods trigger your intolerance. When adding foods back into your diet it is best to introduce them individually. When reintroducing foods look for symptoms such as;

  • Joint pain
  • Headaches or migraines
  • Fatigue
  • Difficulty sleeping
  • Changes in breathing
  • Bloating
  • Stomach pain or cramps
  • Changes in bowel habits

Experiencing these symptoms or not with certain foods will determine what foods you are tolerant or intolerant to (Ramen).

Following an elimination diet is the at-home gold standard when it comes to determining whether or not you may have a food intolerance. With everything you try at home though there a few key things to remember when starting or following an elimination diet;

  • Elimination diets should not be done long-term for this could cause nutritional deficiencies
  • Children should not try elimination diets unless supervised by a doctor
  • If you suspect you are having certain food allergies you should only try an elimination diet under the supervision of a doctor.

If once completing an elimination diet you are still experiencing symptoms there are other options. You can purchase in-home food sensitivity tests or consult your doctor about getting the test done.

Kubala, Jillian. “The 8 Most Common Food Intolerances.” Healthline, Healthline Media, 25 Jan. 2018,

M, N. (2019). An exploration of food intolerance in the primary care setting: the general practitioner’s experience. – PubMed – NCBI. [online] Available at: [Accessed 6 Nov. 2019].

Pongdee, Thanai. “Food Intolerance Versus Food Allergy: AAAAI.” The American Academy of Allergy, Asthma & Immunology, American Academy of Allergy, Asthma & Immunology, 1 Jan. 2019,

Raman, Ryan. “How to Do an Elimination Diet and Why.” Healthline, Healthline Media, 2 July 2017,

Robinson, Jennifer. “Elimination Diet and Food Challenge Test for Diagnosing Allergies.” WebMD, WebMD, 21 Nov. 2018,

Winderl, Amy Marturana. “Think You Might Have A Food Intolerance? Here’s How To Figure It Out.” SELF, SELF, 20 Nov. 2017,