Welcome to Keto Sister.  If you are new to ketogenic nutrition and want to know what this is all about, I invite you to start with my Keto Basics series.  Its written in plain English for those who don’t understand high brow scientific or nutrition speak and just want a plain explanation of keto.  It explains the what and why of nutritional ketosis, and also how to modify the diet for your personal needs.

This week’s post continues my Keto Problems series.  While also applicable to those not eating a low carb diet, I find that it becomes a particularly relevant topic when you begin to eat a low carb diet.  And this knowledge could save your life one day.  I want to explain how to determine whether you have a reaction to a certain food and what to do about it.

Allergy or sensitivity?

There are clinical differences between having an allergic reaction and a sensitivity in response to eating a food.  With an allergic reaction, the immune system becomes involved in how your body responds to a food (Ferguson, 1992).  If your response to eating a food is to develop an immediate urgent reaction (urticaria or hives, throat closing, wheezing, inability to breathe) or a chronic reaction (eczema, asthma, flushed cheeks, sinusitis), then you are in fact having an allergic reaction to a food.  Urgent reactions cause the release of histamine in the body and cause a systemic reaction (AAFA, 2017).  These are often easily identified because they require immediate medical attention and often cause us to fear for our lives (I have a severe allergic reaction to shrimp so I have experienced this first hand).  Without a personalized epinephrine injector (epipen), many of us would be in serous trouble after being exposed to an allergen.

Those of us who have more chronic reactions to food can confuse this reaction with a food sensitivity or even with having a bad day.  A food sensitivity does not cause an immune response but it does usually create a digestive response (AAFA, 2017).  Rather, they reflect an inability of your body to process a certain food.  This may be due to lacking certain digestive enzymes and can result in headaches, nausea, abdominal pain, diarrhea, coughing, swelling, etc.

Whether you are having a food allergy or a food sensitivity is irrelevant to me.  Because we are not medical doctors or scientists concerned with the subtle nuances between the two, what is critical is recognizing when you are reacting to a food which you are not tolerating well.  There are treatments suggested for relieving the response, and some are more effective than others (Schneider and colleagues, 2010, address many ways to treat a food allergy).  But identifying a food that bothers you is the first step to determining the best course of action long term.

Allergy and Keto Diets

The issue of food reactions comes up frequently in low carb circles because many of the foods that create top allergic and sensitivity responses are low carb favorites.  Besides wheat which is not a low carb food, keto enthusiasts often enjoy the other seven top allergenic foods: dairy, peanuts, tree nuts, seafood, shellfish, soy and eggs.

With so many foods being off limit to those following a ketogenic protocol, the foods listed above often represent the sinful, tasty, most delicious food categories still allowed on a keto diet because they create a low insulin response.  However, there is more to watch out for than carb content of a food.  In fact, many people are surprised to find out that they are sensitive to vegetables.  Dr. Georgia Ede has written and spoken about sensitivities to plant foods and is the only scientist with whom I am familiar to explain that vegetables are not always good for us (see http://www.diagnosisdiet.com/food/vegetables/ for details).

How do I know if I have a food sensitivity?

Most people who are allergic to peanuts have an urgent and immediate response, so they know already.  However, sensitivities to foods like nuts and dairy are so common that I start all of my clients off without nuts and dairy for the first 30 days. How do you know if this applies to you? There is a simple way to find out.

1) Eliminate the potential offending food (dairy, nuts, peanuts, soy, eggs, fish, shellfish, vegetable, etc.) for two weeks minimum, although four weeks is better.  When I say eliminate, I mean be strict and do not eat it in any quantities.  Come on, you can do it!
2) Eat one serving every day after the two (four) weeks has passed.
3) If you notice any changes, such as stuffy nose, weight gain, red skin, itchiness, puffy face, skin rash, diarrhea, bloating or gas, etc. then you have a reaction to the food.  My suggestion for immediately dealing with this is to avoid eating it temporarily.

Gone Forever, or Will Gut Healing Help?

I am so glad you asked this question!  In many cases, unless you are having an allergic (immune system) reaction to a food, your sensitivity can be improved.  While avoiding the food, here are a few additional strategies to help heal your gut if this is the cause of your reaction.

  1. Avoid dairy and wheat products. These foods are notorious for damaging the lining of the gut and creating leaky gut.  Leaky gut can cause your body to react to many foods that did not used to bother you before.  Avoiding them is the first step or you will never be able to heal any gut problems you are having.
  2. Take l-glutamine powder on an empty stomach twice a day. Glutamine helps the body to rebuild a damaged intestinal lining.
  3. Eat collagen and/or gelatin. The body uses this similarly to l-glutamine powder.
  4. Eat fibrous vegetables. Soluble fiber works as a prebiotic, or food for gut bugs.  Having a healthy and well fed gut microbiome is critical to being able to digest foods.
  5. Take quality digestive enzyme. If you struggle to digest a food because of a shortage of a specific enzyme, then taking the enzyme can assist your body when you eat that food.  Sometimes taking digestive support like enzymes can help a damaged gut until it can regain its ability to digest foods again fully on its own.
  6. Consider taking quercetin, bromelain, vitamin C or DAO as anti-histamines. These products can be very soothing to the body when having a reaction to a food.  Keep in mind, however, that these are natural antihistamines so they can stop the histamine (or immune) response to a food.  They may not necessarily reverse a food sensitivity like healing the gut will.

I have tried this elimination protocol with unexpected foods and found that I react to foods when facing certain immune responses such as a cold or virus.  Healing the gut can go a long way in helping you to distinguish whether you have a true allergy or a sensitivity.  Once you determine once and for all whether or not you can eat a food, then you can work to build the most delicious diet for you that also supports your gut health.



Asthma and Allergy Foundation of American (AAFA) (2017).  http://www.aafa.org/page/welcome.aspx

Ede G (2012) Diagnosis: Diet. http://www.diagnosisdiet.com/food/vegetables/

Ferguson A. (1992)  Definitions and diagnosis of food intolerance and food allergy: consensus and controversy.  J Pediatr. 121(5 Pt 2):S7-11. Review. PMID: 1447636

Schneider Chafen JJ, Newberry S, Riedl M, Bravata DM, Maglione M, Booth M, Sundaram V, Paige NM, Towfigh A, Hulley BJ and Shekelle PG. (2010) Prevalence, Natural History, Diagnosis, and Treatment of Food Allergy: A Systematic Review of the Evidence. Santa Monica, CA: RAND Corporation. https://www.rand.org/pubs/working_papers/WR757-1.html.