Problem Foods & Exclusion Dieting

woman with stomach pain

Most people don’t feel 100% all of the time. This is normal, and it could be attributed to a million and more different factors. That being said, what if you could spot a pattern? And what if, by making a few alterations based upon that pattern, you could manage your own symptoms? This week we’re going to talk about problem foods and exclusion dieting.

A problem food is something that your body does not ‘like’ very much. These fall under two categories – allergies and intolerances – which are different and cause different responses. If there is a food which causes you to have issues, removing it from your diet can make a night and day difference to your energy levels, wellbeing and of course your overall health. This week I will explain what an intolerance is and what an allergy is, we will tell you how to spot one and then explain what to do about it.


Briefly, an allergy is an immune response to a food, similar to hay fever or a cat allergy but potentially a lot more severe. They happen when your body produces antibodies called IgE antibodies to fight off allergens that are contained in certain foods. This means that someone is not allergic to, say, milk, they have an allergic reaction to the S1-Casein protein within milk, and this allergy will present every time someone consumes this protein whether it comes from milk, cheese, cream or any other source.

This allergy causes various unpleasant and potentially severe things to happen.

Symptoms include skin reactions, which include itching and rashes (urticaria); swelling (angioedema); gut symptoms, vomiting, tummy pain, diarrhoea; respiratory symptoms such as blocked or runny nose, coughing and wheezing. The most severe reaction, anaphylaxis can be incredibly traumatic and is potentially fatal. These symptoms usually develop rapidly making a ‘normal’ allergy pretty easy to spot.

There is, however, another form of food allergy known as a non-IgE allergy in which your body can react to an allergen but with a delay of up to three days – these are caused when your immune system reacts to something but does not produce specific IgE antibodies to do anything about it. This is highly uncommon but it does occur in children and can very occasionally present in adults. Symptoms often include inflammation to the gut, with pain, vomiting, diarrhoea or constipation but also skin issues (in fact, this is often present in children but diagnosed as eczema). Because of the delay in symptoms appearing it can be quite hard to pin down exactly what it is which is causing you issues, but fortunately allergy testing is relatively easy to perform and often freely available through your NHS GP.

Around 8% of UK children and 2% of UK adults have a food allergy, with the most common problems being (in order of prevalence) peanuts, tree nuts (such as almonds, brazils, walnuts), eggs, milk, fish, shellfish, sesame, soya and wheat. If you suspect any food, but especially the above, is causing you allergic reaction-like responses, or if you are experiencing allergy symptoms which don’t immediately follow certain foods (but potentially are coming from something you’ve eaten a few days previously) then ask for a test as a diagnosis is often easy to get.

Allergies are not the only thing that can cause a food problem, there are also intolerances.


Intolerances are a little harder to define and diagnose, as they do not involve IgE antibodies or, indeed, the immune system at all, so cannot really be tested for, accurately anyway. There are currently no known tests that can diagnose a food intolerance other than lactose intolerance which is caused by your body not producing lactase, the enzyme needed to break down the sugar in dairy – lactose. There are many tests available, but none are scientifically proven and as such should be viewed with extreme caution as potential (likely) scams.

The actual cause of problems is relatively unclear for most food intolerances – though the symptoms are very similar. Symptoms are generally gut related and include (but are not limited to) bloating, diarrhoea, IBS, constipation and gassiness, though skin irritation, joint pain and other symptoms are and can be among other possibilities. Some non-specific and vague issues are typically reported secondary to these prime symptoms, including ‘brain fog’, lethargy and headaches, though these could very well be psychological implications of the above ‘truer’ symptoms. Either way, food can play potential havoc with the body if the body reacts to a certain food, or food group, so either way if there is a persistent symptom, consider the diet and direct reactions you may get from certain foods.

Food intolerances are typically transient things, which means that once the food has been removed for a prolonged period (stretching from months to years), you should eventually be able to eat it again. They are usually brought on by a poor overall diet which is low in fibre, high in processed foods, overly low in Calories or filled with foods which are potentially hard to digest (people who eat a lot of raw vegetables like broccoli or cabbage often develop intolerances due to irritating their gut). GI infections are another thing that can cause an intolerance to present itself.

These intolerances could then be triggered by other things such as histamine in foods, or salicylates, or caffeine, or nitrates. There is a huge range of intolerances which carry similar symptoms, meaning that pinning down what YOUR problem is could take some time and may need more professional help.

(Remember, the exception to this is lactose intolerance which has a clear-cut cause and can be directly tested for.)

Much like non IgE allergies, intolerances will often present their symptoms hours and even days after eating a certain food which only makes it even harder to pin things down, so if you DO suspect a food problem due to experiencing the above symptoms, your best bet is to do the following:

  • Keep a diary of foods eaten and how you ‘feel’ to see if you can draw patterns. Most intolerance issues present within a few hours so this could help. Once you pinpoint something (for example, 3 hours after eating mature, hard cheese you get cramping or a phlegmy throat).
  • If you spot a pattern, remove the food for a period of two weeks and see how you feel. If things don’t get better, look harder, otherwise you may have found the course and a break from this food while improving your diet to support your health and healing is the best option.
  • If a pattern does not emerge, speak to your GP and ask for an allergy test to rule that out. If the test comes back negative and you are still experiencing symptoms which are hard to relate to a certain thing, ask for a dietician referral because you are then needing to consider a specific exclusion diet.

Exclusion Diet

This is a dietary intervention that removes common problem foods and/or suspected problem foods that you highlight for yourself, in an effort to remove symptoms. Once symptoms are no longer presenting, all that remains is to add those foods back in again, one at a time, and keep a close check to see what causes the reaction. Once you find out, simply remove that food and carry on as normal, enjoying a far better state of health! Once this food has been removed and you have been symptom free for 6 months or so, it’s worth trying to gradually re-introduce it to see if you have ‘fixed’ the problem.

(please remember, allergies and intolerances are different in a number of ways – one of them being that allergies are permanent)

It’s important that you speak to a doctor and then dietician first, as exclusion diets are very likely to result in certain nutrient deficiencies owing to being so restrictive if not done properly, and therefore it’s imperative that you get some kind of professional guidance. After all, you’re looking to improve your health with an intervention, so there’s no point in cutting out problem foods and ending up with a micronutrient deficiency.

Food Groups

When you do identify a certain food, you can then relate this to it’s food group to ensure you remove all the offending foods. For example, if you bloat or get IBS symptoms from bread, it is likely then a gluten or wheat problem, identifying other foods that contain wheat and gluten are extensive, so do your research and find all the foods that contain either wheat or gluten, which will include pasta, cakes, biscuits, sauces, flour based foods and much more. So once you do identify a food, relate it back to its food group.


Any food can create any manner of issues in the human body, and to reach a state of optimal health it’s important to identify ANY possible problem foods as they will hold your health back. If you don’t have any symptoms or areas of your health that need attention, then by all means this is not something that needs as much of your attention, but I want you to at least spend this week listening to your body, finding clues and seeing if there are areas of your health that can be improved.