Food Intolerance v Food Allergy

The difference between a food allergy and food intolerance / sensitivity

Food intolerance / sensitivity’s and food allergies are often at the heart of slow results in the fitness game.  Many people ask me why I don’t suggest eating gluten, milk and non organic food.  Food intolerance / sensitivity is the main reason, but you need to understand the difference between an intolerance / sensitivity to an Allergy.

Food Allergy

This is an immunological reaction to food proteins.  In simple terms, a “food allergy” represents a reaction to food (called an allergen) that stimulates the defence system (also known as your immune system), to produce antibodies against that specific food.

When you have an immune response to food the body literally attacks itself.  A good example of this is in coeliac disease.  In coeliac disease, gluten reacts with the small intestine and activates the immune system to attack the delicate lining of the bowel. The normally rippled lining of the intestine becomes damaged and highly inflamed, and forms the characteristic flat appearance of coeliac disease. The surface area, which enables the absorption of nutrients and minerals from food, is seriously depleted, leading to gastrointestinal and malabsorption symptoms.

Food allergy’s can be tested by measuring IgE response and can be identified by skin prick tests or RAST blood tests and confirmed with avoidance and challenge.

Food Intolerance / Sensitivity  is a pharmacological reaction (like the side effects of a drug)  to foods – and more importantly chemicals in foods – that does not involve a immune system response.

Various chemicals present in the food can cause food intolerance.  Some examples include enzymatic intolerance’s such as lactase deficiency (it is estimated 70% of people lack the enzyme lactase needed to break down the sugar lactose so why you drinking milk ya big baby??), pharmacological intolerance’s such as histamine, tyramine and serotonin naturally found in foods, and intolerance’s to food additives such as coloring’s (tartrazine, dyes), flavorings (MSG, aspartame), preservatives (sulphites, benzoates) and anti-oxidants (BHA, BHT.)

A MRT LEAP test can be done to determine intolerance / sensitivity. But one of the best and easiest ways is through an elimination diet and then re introducing to see specific foods one at a time to see how they effect people.

The Sensitivity Spectrum

A new concept:

Think of food intolerance as food sensitivity.  Above is an example of a spectrum ranging from ‘coeliac’ to ‘no response from gluten’ to give you an example.  We all exist on it somewhere.  Some coaches claim the number of people sensitive to gluten for example is 90%, other more conservative reports are around 50 – 70%.  From my experience though?  I know few people who tolerate gluten well once its removed.


Allergic Reactions can be itching, swelling, rash, spreading hives, vomiting, diarrhoea, breathing difficulties and in the most severe of the allergic disorders, anaphylaxis can lead to collapse and death. By definition, anaphylaxis is an allergic reaction which involves two of the body’s systems (e.g. respiratory and gastrointestinal or skin). Anaphylactic deaths as a result of insect bites or penicillin are usually very quick – within minutes – and due to cardiac arrest, anaphylactic deaths due to food allergies are usually due to suffocation (breathing difficulties).

Food intolerance reactions can be the same as above, as well as: rashes, skin swelling, asthma, stuffy or runny nose, frequent colds and infections, irritable bowel symptoms, colic, bloating, diarrhoea, vomiting, frequent mouth ulcers, reflux, bedwetting, ‘sneaky poos’, ‘sticky poos’ migraines, headaches, anxiety, depression, lethargy, impairment of memory and concentration, panic attacks, irritability, restlessness, inattention, sleep disturbance, restless legs, mood swings, PMT.

Symptoms of food intolerance can come and go and change throughout life most likely due to exposure times.

Response Time

Allergic reactions are quick. They usually occur within 30 minutes and are often easy to identify.

Food intolerance reactions can be delayed up to 48 hours or more, or effects can be cumulative. For instance, children rarely react to the preservatives in one slice of bread, but if they eat bread every day – as children do – the effects can build up over a month and fluctuate with no obvious cause.

People often don’t realize they have an intolerance until the food is removed.  This has been my experience for years and years as a trainer especially with gluten.  Being a coeliac is an extreme reaction to gluten but most people are intolerant from my experience.  The gluten sensitivity is slowly entering the mainstream as it becomes obvious that people who do not suffer from coeliac disease also benefit from gluten free diets, not only in terms of body composition, BUT HOW THEY FEEL!

Main Culprits

Food Allergies – In Australia the most common food allergies are milk, soy, egg, peanut and fish. Allergies to peanuts are the most likely to be life-threatening.

Food Intolerance / Sensitivity –  All of the above and gluten, wheat.  Food chemicals most likely to cause problems are artificial colours, natural colour annatto (160b), Pesticides, herbicides, fungicides, preservatives, flavour enhancers (the 600 numbers) and some natural chemicals called salicylates and amines. These can be in many different and seemingly unrelated foods. For example, asthmatics are most likely to be affected by sulphite preservatives (220-228) in dried fruit, juice drinks, cordials, wine, sausages, some medications and a wide range of other foods.

What can you do?

Food allergies: If you have an allergy avoidance with regular testing is best.

Food intolerances: Get a MRT LEAP test.  But because of the vagueness of intolerance / sensitivity an elimination diet with challenges to pinpoint the culprits, then gradual reintroduction of certain foods to ascertain tolerance, and subsequent avoidance is the easiest and less expensive option.  Feeling better is also the quickest response you can get.

Rotating food as often as possible also seems to minimize intolerance / sensitivity and is the sole reason for rotating food.  To minimize sensitivities.

Once again this has been my experience for years and years with gluten.  The hard part is getting people to not eat it as its everywhere!

Gluten sensitivity and the sensitivity spectrum are relatively new ideas and not fully understood at all.  I still read and talk to nutritionists who claim that if you’re not a coeliac you should eat gluten.  But its not an all or nothing situation for me as from experience if you take the inflammatory food out, people feel better within two weeks.  They sleep better and they have constant energy through out the day.  No afternoon crashes.   When I allow them to re introduce the inflammatory food and they feel sick.  One girl recently vomited for 3 hours after eating ice cream after going clean for 2 weeks!  Er, no further testing required!

I know this may be hard to swallow for some (har har!) but being strong and lean is a lifestyle.  As is being gluten free.

See you in the gym!

Brad Stocks
Personal Trainer
Bondi Junction

Dr Alessio Fasano
Dr. Eric Serrano
Dr Peter Osbourne
Charles Poliquin

  • Judith Batt says:

    Great news

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