Food Intolerance: Just fussy eating?? Fad, friend or foe?

We are what we eat and it will affect how we feel. I recently attended a dinner party where each of the 12 guests had at least 1 dietary requirement. This is a relatively new normal, but food intolerance, to some degree, is thought to affect more than half of us.

There can be a lot of confusion surrounding this topic, with labels such as food hypersensitivity, food allergy and food intolerance often being freely interchanged. It is important to make the distinction between a food allergy and a food intolerance because the management can be quite different.

A true food allergy is relatively rare. It affects approximately 1% of the adult population and common allergies include nuts and shellfish. Here, the body sees the proteins found in the culprit food as a threat, and tries to attack it – this is called an immune response.

Symptoms of an allergic reaction usually start immediately (although sometimes a delay of a few hours can occur) and can include tingling in the back of the throat and lips, a rash and vomiting and/or diarrhoea. In more severe cases, it can lead to swelling of the face and breathing difficulties. This is called anaphylaxis and is a medical emergency. The treatment is adrenaline injected in to a muscle as soon as possible, and so once diagnosed, you may be asked to carry an EpiPen with you at all times. You need to avoid this food for the rest of your life.

This attack (or immune response) usually releases an immunoglobulin called IgE and this is what we check for when performing an allergy test. The 2 most common allergy tests are a skin prick test or a blood test known as a radioallergosorbent (RAST) test. Non IgE mediated allergies do exist, but these are more common in children. Speak to your doctor for more information.

An intolerance is different. Your body finds it difficult to break down and digest certain substances in foods but no allergic reaction place. Common intolerances include:

  • Dairy
  • Gluten
  • Wheat
  • Yeast 
  • Alcohol


Gluten free


It can take quite a long time to diagnose an intolerance or identify a trigger food, and there are many reasons behind this. Sometimes your body can tolerate a small amount of the food, but when eaten in larger quantities it can be troublesome. Often, you might just notice that you don’t feel quite right but you can’t quite explain why. You can feel tired and sluggish or notice problems with your skin. You may become constipated or have diarrhoea or a mixture of the two. Commonly, you can feel very bloated and you may find yourself passing more wind, which can be embarrassing.

It is not uncommon for your symptoms to change from day to day, or get worse over time. They can start to have a negative impact on day to day life and overall make you feel quite miserable!

the best place to think

If you are having any of these symptoms, book an appointment with your GP. They will take a full history, and ask questions such as: Have you had any change in your bowel habit? Have you noticed any blood in your stool? Have you had any weight loss? Your GP may also carry out basic investigations such as blood tests and possibly a stool sample to rule out things like coeliac disease, inflammatory bowel disease and even bowel cancer.

If you are given the ‘all clear’ for any specific cause by your doctor, it can take a while to accept there is no magic solution to the very real symptoms that you are having. They will probably advise you to make changes to your diet, and although it may feel like a bit of a cop out, this really is the management.

Your GP may mention the FODMAP diet to you, it stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols. Foods containing these short chain carbohydrates are difficult to digest because they attract water and feed gas-generating bacteria inside the intestine, which leads to bloating, flatulence and loose stools. This reaction affects some people more than others. The list of foods to avoid on the FODMAP diet can appear endless, but when done properly, it can make you feel a lot better.

iStock_000020778541_Large copy

Your doctor may make other suggestions about what to avoid in your exclusion diet and most often they will recommend a referral to a dietician or nutritionist for support and guidance. It is essential that we ensure you are still getting all the nutrients you need, despite making quite significant changes to your diet. The aim is to exclude a food for a period of time and then re-introduce it slowly and monitor for return of any symptoms.

Can’t I have blood test to check what I am intolerant to?

To be honest, there is no scientific date supporting the accuracy of this test. The most common commercially available tests look at the level of Immunoglobulin G in response to hundreds of different foods and report whether you have a reaction to them. I would advise caution when thinking about getting one, and don’t get one done without consulting a doctor.

That being said, I sympathise fully with sufferers, and being one myself, as a desperate last resort, I paid to have one done. I found my results very interesting (and a little depressing – I couldn’t eat anything I loved!!) Here are my results:


R = Reactive and I should eliminate B = Borderline reaction (may or may not be helpful to eliminate)

There are also lots of other commercially available tests claiming to diagnose food intolerances. Novak Djokovic has famously used kinesiology which uses muscle testing to detect imbalances in the body and he has since cut out gluten amongst other things from his diet. Please speak to your doctor before paying lots of money to get any of these tests done, as the scientific evidence backing these methods is limited.

Food intolerance is real, and it can have a significant effect on people’s lives. If you are having symptoms then the first port of call should be your doctor to rule out any serious illness. Food intolerance tests are expensive, and not entirely backed by science, but some do find the results helpful as a guide. Usually, I find this is because it gives them focus and motivation to control their diet, which really is the key. Make use of a dietician or nutritionist to ensure you stay healthy.

Good luck with anything you are advised to try – its not easy but it will be worth it!


One thought on “Food Intolerance: Just fussy eating?? Fad, friend or foe?

  1. Really well explained Dr Pri! Think with so many diet fads around these days , it can become really confusing understanding your own body and knowing what signs to looks out for when you eat things that do not agree with your digestion. A really useful article 🙂

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