The Twelve Signs of Food Intolerance

The Definition of Food  Intolerance:

    • Food intolerance used to be defined as the inability to fully digest a food. This blames the sufferer.

    • Accumulating scientific evidence however has changed this view: we now understand symptoms of food intolerance as the unfavourable consequences of poisoning by food toxins. This correctly blames inappropriate food choices.


How common is Food Intolerance?

    • Around 3 in 4 people have some kind of food intolerance - but most are unaware


Sign  # 1. Anaemia:

Sign: Low iron levels, or anaemia. Lacking energy, pallor or breathlessness? It may be anaemia.

Leaky Gut syndrome: When you cannot digest 'modern' foods like grains, nightshades or dairy foods your gut can become damaged, in particular the small intestine. The tissue develops tiny holes and becomes 'leaky'.

Then its ability to absorb nutrients like iron and calcium is compromised.

Good things are lost from your body without being absorbed. Check yourself for food intolerance - even if it has never occurred to you. More about Leaky Gut >


Sign # 2. Mouth ulcers

Sign: Mouth ulcers - so painful, so long lasting! Mouth ulcers mean we suffer in silence for days, have difficulty eating, talking - even brushing your teeth. And there seems to be no effective treatment. Ask yourself ... why? 

The appearance of one or more mouth ulcers is a sign of a temporarily stressed immune system. In other words your immune resources are stretched to capacity and cannot even throw off a minor mouth infection.

But if you have undetected food intolerance - the 'problem' foods are generating 'foreign' things which consume immune resources. So while your body is busy fighting these things, infections can jump in where they would usually not get a chance.

Mouth ulcers are a hallmark sign of food intolerance. We recommend a program that tracks foods eaten against symptoms. 

Learn about foodintol® LoTox Living


Sign # 3. Irritable Bowel Syndrome - IBS

Sign: Alternating sessions of constipation and then diarrhoea. Along with these distressing symptoms come others:

  • Malabsorption of nutrients because your intestine is not functioning properly
  • Dehydration
  • Rectal and anal trauma - leading to haemorrhoids
  • A blue mood

IBS is common - but few doctors will suspect FOOD TOXINS as possible culprits.

We believe it is better to find and remove the cause - than to keep on treating something with medications. Removing the cause is a permanent solution! Irritable Bowel is almost always food-related. and the Journal Method will give you actual proof - one way or the other. 


Why now? From tolerance - to intolerance


Why can we be all right eating all those foods for all those years - and suddenly - out of the blue - they start making us sick?

In fact you have had the intolerance all your life - from before birth.

It's just that young bodies are 'tolerant' to all kinds of abuse - from fast foods to alcohol.

But as we get older our bodies become less tolerant . . . so we might get a very noticeable symptom: bloating, headache, skin rashes, arthritic joints or worse.


Sign # 4. Headache, migraine

Sign: Headaches which have become routine, or occur every day - or every week. Or migraines which keep you home form work. The medical research evidence says these could be from the 'foreign' things generated by foods you cannot fully digest . . . or food intolerance.

Wouldn't it be great to know which food causes yours?


Sign # 5. Chronic cough, sinusitis, bronchitis, asthma, colds and 'flu:

Sign: Chronic respiratory conditions are frequently related to food intolerance. Once again it is the immune system responding by generating inflammation - this time in the lungs and nasal passages. But getting the diet right alleviates symptoms permanently. This is especially important for children who might otherwise miss learning opportunities.

Find the cause and remove it from your life More on respiratory issues >

Sign # 6. Eczema, psoriasis and chronic skin conditions:

Sign: Chronic eczema. Many people are surprised to find out that food intolerance can cause skin conditions like eczema. The inability to fully digest some foods leaves 'foreign' particles in your gut - which leak through into the bloodstream. Your body tries to get rid of them by sending them to the skin where inflammation eventually erupts into red itchy patches which may weep with fluid and cause skin to peel off.

Another skin condition Psoriasis is also causatively linked to food intolerance in the medical literature. But moving to the correct diet removes the flow of 'foreign' things to the site (removes the cause) - and allows the skin to heal naturally.

Clear skin is important to anyone - but especially so for children and teenagers who are still developing their sense of self worth and self esteem.


Sign # 7. Aching joints, backache

Sign: Chronic stiff joints or back pain. When you have food intolerance your body is unable to fully digest certain foods. Unexpected products are generated - and some of them are not recognised as 'friendly' by your immune system. So an immune response takes place - inflammation - and this commonly appears in the leg joints (leg pain) or joints of the spine (backache, arthritis). 

So if your arthritis or backache has been caused by food intolerance - you may begin to heal it - by reducing food toxins.


Sign # 8. Gradual weight gain - or weight loss

Sign: slow weight gain - or unexplained weight loss. When you have unrecognised food intolerance - your thyroid gland can be affected. That means your metabolism gets disrupted. The thyroid gland processes your food either into energy (to burn) or into fat (to be stored for later use).

Mixed up signals means you 'store' when you should be 'burning' (weight gain). . .or vice versa. People who seem to stay thin regardless of what they eat probably have undiagnosed food intolerance - because they are unable to absorb nutrients from food. Getting back to your ideal size happens gradually with a LOW-TOXIN DIET.


Diane: When I stopped eating those foods, my life changed, seemingly overnight.  I lost eight pounds in 6 weeks;  I'm short and have a petit frame, so every pound shows on me.  Since August, I have lost close to 15 lbs.  Not even trying . . . My cholesterol has plummeted as well, to 187, down from a high of 264.


Sign # 9. Tinea or Yeast (Candida) infections

Sign: Candida, thrush jock itch, ring worm or athlete's foot - it is a hallmark of untreated food intolerance. When your immune system is busy fighting half-digested things it thinks are 'foreign' - your defences are down. That's when fungal infections like candida albicans jump in and flourish.

If you do get fungal infections, deal with the Yeast issue first - by ridding your body of candida (fungal infection) - then you must tackle the underlying food intolerance - or else it will come back again.


Sign # 10. A colicky baby

Sign: A baby with colic is a baby suffering the symptoms of food intolerance. A very sore and distended intestine - as she or he tries to digest the indigestible It certainly applies to exclusively breast-fed babies as well as others.

But how can this be? Isn't breastmilk best?

Yes, of course. But what if the baby's father has some food intolerance? He may know about it - or he may not. But even if the mother does not have food intolerance - troublesome particles from her digestion will appear in the breastmilk. And the baby ingests them. And some hours later you all know about it.

Colic is a sadly misunderstood condition - and incredibly painful for the infant - and the new parents - usually stressed enough without this.

The solution as usual is to remove the cause. Let the mother try a grain-free, dairy-free diet and after a few days - things should settle down. Alternatively you can choose an appropriate formula for the child. Also the father should consider using the Journal method to find his food intolerance(s).


Sign # 11. Miscarriage, difficulty conceiving - men and women

Sign: difficulty conceiving or unsuccessful pregnancy. Everybody wants to have a healthy pregnancy and a beautiful healthy baby. Unchecked food intolerance interferes with your ability to conceive and take your pregnancy to full term. The effects apply both to men and women.

So if there has been miscarriage in your family - or if you have ever had one yourself - make sure you investigate food intolerance before trying for another baby. We recommend you don't guess. Get actual proof of your food intolerance.


Sign # 12. Depression, mood swings - or the 'blues'

Sign: 'blue moods or depression. Studies indicate all of the four main food intolerances are linked to early stage depression: dairy, fructose, yeast and gluten. Depression strikes adults - and increasingly - teenagers, and even younger children. However when you track down the culprit food - and substitute it healing begins almost immediately:



'I filled in the questionnaire on food intolerances. I filled it in on behalf of my son who is 12 ... Depression was the main problem . . . and taking those foods out of his diet fixed the depression  - I was amazed!  Rachel T.


I am ready for an immediate solution - what's next? 

Food toxins can cause serious disease. Gluten is just one thing that could be causing your symptoms.

There are MORE THAN TWENTY FOOD TOXINS – and they act together in different combinations to damage cells and provoke the immune system. Learn more with the free ebook on Food Toxins



  1. Varea et al. Malabsorption of carbohydrates and depression in children and adolescents. J Pediatr Gastroenterol Nutr. 2005 May;40(5):561-5
  2. Ledochowski et al. Carbohydrate malabsorption syndromes and early signs of depression in females.Dig Dis Sci. 2000 vol. 45, no. 7, pp 1255-1259

All foodintol® information is based on research from peer-reviewed medical journals