Easy Test For Food Intolerance

If you've been suffering from rashes, stomachaches, or bloating, the cause could lie in your food.


By Jennifer House, R.D.


Maybe you have a rash that just won’t go away or you suffer with tummy aches and bloating or you just feel exhausted. Though you’re already on a healthy diet, the cause could actually be linked to a particular food.

But how do you know for sure if you have a food allergy or intolerance, and how do you figure out which foods are your culprits?

Contact an alternative health practitioner, and many will sell you an IgG blood test. These tests cost you hundreds of dollars, and always comes back showing you are allergic to a significant number of foods –many of which you consume often! Please save your money, as these tests (as well as many others) are not valid: IgG antibodies represent exposure to foods, not allergy!

Another option is a referral to a qualified allergist doctor. They will conduct IgE antibody testing, which is more accurate in determining allergens. However, these tests can still produce false results, and will not detect food intolerances (only true allergies). Even allergists will agree that the best way to determine if you have a food allergy or food intolerance, is an elimination and challenge diet.

While elimination diets are something you can do on your own and do not cost any money, it is helpful to consult your doctor or a registered dietitian to help you identify trigger foods and ensure you have a balanced diet. 

Here are the steps to conduct an elimination and challenge diet:

  1. Before you start an elimination diet, keep a food and symptoms record for two weeks, including timing and the amounts of food you’ve eaten and the symptoms that follow.
  2. If you are able to link any of your symptoms to foods you have eaten, remove these foods from your diet for 4 weeks. Continue to keep a record of your foods and symptoms Try to ensure that you are still consuming a diet that is not missing any nutrients during this phase.
  3. If you notice any improvement, then it’s possible you don’t have food intolerance, or you are still misidentifying the food culprit. Contact a doctor or dietitian that specializes in allergies. If you notice an improvement, then begin adding back into your diet the foods you’ve taken out, one at a time every 3 days – this is the “challenge” portion of the diet.
  4. If you don’t get symptoms from adding in a suspected food, then you can add it back into your regular diet. If you do get symptoms during the challenge, then you know you have difficulties digesting that food.

The good news is that you may have a certain threshold you can tolerate for food intolerances, and some allergies can actually be outgrown. Depending on your problem food, there are some supplements that can help you to digest them, such as Beano for beans, veggies and whole grains or Lactaid for lactose digestion in dairy.

Disclaimer: The medical and/or nutritional information in this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a food intolerance.

Jennifer is a registered dietitian, registered nutritionist, and a member of the Alberta College of Dietitians and Dietitians of Canada. Combining her personal and professional passions, Jennifer loves to blog about food and eating during pregnancy and for young kids and families. You can find her on First Step Nutrition.

Main Photo Credit: stockcreations/; Second Photo Credit: fotohunter/