What Is Food Intolerance and Sensitivity?
A food intolerance (also called a food sensitivity) is an adverse reaction to certain substances found in food.
Unlike food allergy, food intolerance does not involve the immune system.
Rather, these substances act as irritants on the nerve endings in sensitive people.
The symptoms of food intolerance can affect four main systems of the body including:
- Nervous system: headaches, migraines, irritability, restlessness, hyperactivity
- Respiratory system: asthma, wheezing, chronic cough, sinus problems
- Gastro-intestinal tract: recurrent mouth ulcers, reflux, nausea, bloating, stomach pain and cramping, altered bowel habits
- Skin: eczema, hives, other skin rashes.
Common Triggers of Food Intolerance and Sensitivity
The most common naturally occurring substances known to trigger symptoms include:
- Salicylates: found in many fruits and vegetables, herbs and spices, honey, tea and coffee, wine and beer
- Amines: found in aged products such as ripened fruit and vegetables, cheese, wine and beer
- Glutamates: a natural flavour enhancer found in savoury foods such as cheese, mushrooms, tomatoes, grapes
- FODMAPs: poorly absorbed sugars found in a variety of fruits, vegetables, grains and dairy products
- Dairy milk protein: found in cow’s milk products such as milk, yogurt and cheese
- Gluten: found in products made from wheat, barley and rye. Although new research indicates gluten is not the issue unless you have celiac disease.
- Soy: found in products made from soy beans.
There are also a number of artificial additives known to trigger symptoms:
- Colours: added to a wide variety of foods such as lollies, cakes, sauces and many more to change or improve the colour of the product
- Preservatives: added to extend the shelf-life of products
- Antioxidants: also added to preserve particular products and extend their shelf-life
- Flavour enhancers: added to enhance the flavour of bland foods.
Elimination Diets For Diagnosing and Treating Food Intolerance
Food intolerance does not involve the immune system, nor is there any evidence of actual disease.
This means that when medical investigations are completed by doctors, test results come back as negative.
Thus, the only way to diagnose food intolerance is through structured medical elimination diets.
These elimination diets have three phases:
- Elimination: suspected trigger substances are temporarily removed from the diet
- Re-Introduction/Re-Challenge: individual trigger substances are systematically re-introduced/re-challenged one at a time to identify which substance is responsible for triggering symptoms and in what amount
- Personalise: tolerated substances are re-introduced into the diet and trigger substances are avoided.
The most common elimination diet used is the low FODMAP diet.
However those who do not find success with this diet may do better on the FAILSAFE diet / RPAH Elimination diet for food chemical intolerance.
More Information on Food Intolerance and Sensitivity
11 Warning Signs You Have A Sneaky Food Intolerance
Food Chemicals and the FAILSAFE Diet (RPAH Diet): The Beginner’s Guide
Salicylate Intolerance: The Complete Guide + List of Foods
Histamine Intolerance: Everything You Need To Know Explained in Plain English
Fructose Malabsorption: A Beginner’s Guide to Treatment
Digestive Enzyme Supplements: Splitting Fact From Fiction
Lactose Intolerance: What You Need to Know to Live a Normal Life
6 Signs and Symptoms of Gluten Intolerance
All articles about Food Intolerance and Sensitivity
Prevent Diverticulitis Recurrence: 5 Things To Fix Before Your Next Flare
As a gut health dietitian service, we see a lot of diverticulitis cases — and honestly, the pattern we see most often is this: someone has a flare, they recover, they change nothing, and a few months later they’re back in the ER. Not because they did anything wrong, but because nobody told them what to actually fix.
I was on a call with a client last month who’d just come out of hospital with her second diverticulitis flare in two years. She said, “Joe, they gave me antibiotics, a leaflet about soft foods, and sent me home. Same as last time. Nobody told me why it keeps happening.” That’s a conversation I have constantly, and it’s exactly why I put this together.
Here are the 5 things you should be doing after a flare, and why most people never get told about them.
Below is a video we made; there is also a written version underneath.
[Discover More…]Top 5 IBS Red Flags Patients Ignore
I want to preface this by saying a majority of people with IBS aren’t ignoring warning signs because they’re careless. They’re ignoring them because they’ve been told everything is fine. Normal colonoscopy. Normal bloods. Here’s a food list. Off you go.
And then years pass, and they’re still planning their days around the nearest bathroom.
Below, I walk through five red flags that IBS patients, and honestly a lot of GPs, commonly miss. Many of these are signs that your current plan isn’t good enough, and what you can do about it.
Here’s a video we made; there is also a written version underneath.
[Discover More…]Acid Reflux, GERD and Heartburn: What Actually Helps?
A dietitian explains the food, meal-timing and daily-habit factors worth checking when acid reflux, GERD or heartburn keeps returning.
The GERD Diet: What To Eat, What To Limit, and Why Trigger Lists Conflict
A practical explanation of GERD food triggers, gentler starting choices, meal timing and why one universal reflux diet does not exist.
Silent Reflux (LPR): Why Throat Symptoms Can Happen Without Heartburn
A careful explanation of silent reflux and LPR, why throat symptoms are not specific to reflux, and which food and meal habits are worth reviewing.
Low FODMAP Diet Basics: What I’d Do in the First 7 Days
Most people start the low FODMAP diet the same way: they delete half their diet on day one. By day three, they’re eating plain chicken and rice, running out of ideas, and quietly wondering if there’s anything left they can actually eat.
That’s not a failure of willpower. That’s a failure of having a plan.
If you’ve Googled “low FODMAP diet” and felt instantly overwhelmed by giant food tables and fifty different serving sizes to memorize, you’re not alone. Most people quit before they ever really start properly — not because the diet doesn’t work, but because week one goes wrong in predictable ways.
Below, I walk through exactly what I’d do in the first seven days: what to pull out, what to keep, what to eat, and the traps that catch most beginners before they ever get to reintroduction.
Here’s a video we made; there is also a written version underneath.
[Discover More…]IBS-D: 5 Signs You Need More Than a Food List
If you’re still planning your life around bathrooms even while eating “safe” foods, your IBS-D probably needs more than another food list.
Because food can matter. A lot. Lactose-containing dairy can matter. Coffee can matter. Fatty meals can matter. Other FODMAPs can matter.
But if the list keeps getting longer and your confidence keeps getting smaller, food may only be one piece of the pattern.
This is the question people keep asking in different ways: “I’ve found my trigger foods, so why do I still have urgency?” Or, “Why are there no fully safe foods?” Or, “Why do I eat the same meal twice, and only one time it sends me running?”
In this article, I’ll show you five signs your diarrhea-predominant IBS needs a bigger framework than “avoid this, eat that.” And the last one is especially important because some symptoms deserve medical review, not another diet sheet.
Here’s a video we made; there is also a written version underneath.
[Discover More…]The Diverticulitis Antibiotics Mistake
Doctors used to treat diverticulitis almost automatically with antibiotics. You had the pain, you got the scan, and very often the next step was a prescription. But the advice has changed.
Antibiotics aren’t for everyone and aren’t meant to be used in every situation. And please don’t hear this as “never take antibiotics.” That would be dangerous. But for selected cases of mild, uncomplicated diverticulitis, the newer guideline position is much more nuanced — antibiotics are no longer treated as automatic, because in those selected cases, they don’t appear to speed recovery or prevent recurrence the way we once assumed.
And that matters, because a lot of people are still working from the old model: “I had a flare. I took antibiotics. Therefore, I’ve handled the diverticulitis.” That’s the real mistake. Not taking antibiotics when they’re needed — the mistake is thinking antibiotics are the whole plan.
In this article, I’ll walk you through what changed, when antibiotics still matter, what the main studies found, and the exact questions to ask your doctor after a flare so you’re not just waiting for the next one.
Here’s a video we made; there is also a written version underneath.
[Discover More…]Why You Look Pregnant By The End Of The Day
If your stomach looks fairly normal in the morning but by dinnertime you look six months pregnant, you are not imagining it.
This is one of the most common things people tell us: “I look pregnant by the end of the day,” or “I feel like I swallowed a watermelon,” or even “My bloating gets bigger as the day goes on.”
And the usual advice is almost always food advice: “cut this food”, “avoid that food,” or “try another list.”
But if your belly is visibly changing throughout the day, food may only be one part of the story.
In this article, I explain the five reasons this can happen, what the timing may tell you, and why a stricter food list is not always the answer.
Here’s a video we made; there is also a written version underneath.
[Discover More…]5 Things That Make Diverticulitis Flares More Likely
Most people with diverticulitis ask the same question after a flare: “What did I eat?”
Was it the nuts? Was it the popcorn? Was it that salad? Was it the steak from three nights ago?
You see the same questions everywhere people talk about diverticulitis: coffee before breakfast, red meat, seeds, constipation, stress, fiber, alcohol, and genetics. People are trying to find the one thing they did wrong.
But flares usually aren’t caused by one magic food. In fact, one large study published in JAMA followed more than 47,000 men and found that nuts, corn, and popcorn did not increase diverticulitis risk — and popcorn was actually linked with a lower risk in that study (1).
So if you’ve been blaming one meal, or one tiny seed, you may be looking in the wrong place. And if you’re thinking, “But I eat healthy, so why did this still happen?” then that’s exactly why we need to zoom out. A Mediterranean-style diet, salads, or high-fiber foods don’t make you immune if the rest of the pattern is still working against you.
Below, I share the five things that make diverticulitis flares more likely and show you how to actually fix the pattern between the flares.
Here’s a video we made; there is also a written version underneath.
[Discover More…]Going Gluten-Free Didn’t Fix Your Gut? Here’s Why
Have you gone gluten-free because your gut was a mess — the bloating, the pain, the cramping — and found that it helped at first, but then the symptoms came back? Or maybe you switched to gluten-free products and somehow started feeling worse?
If that sounds familiar, you’re not doing it wrong. And you’re not imagining it.
The gluten-free food market is worth almost eight billion dollars and growing, with tens of millions of people worldwide currently avoiding gluten. But here’s what most of them have never been told: for the vast majority of people eating gluten-free for gut symptoms, the relief they experienced had almost nothing to do with gluten.
In this article, I’m going to explain exactly why that happens, what’s actually going on inside your gut, and what to do instead so you can eat with far more freedom and far less confusion.
Here’s a video we made; there is also a written version underneath.
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One in three people who have a diverticulitis flare will have another one. Not because they did anything wrong after the first one. Not because they ignored their doctor’s advice. Most of them did everything they were told. The problem is that what they were told was incomplete. And in some cases, the standard approach may actually be making the cycle worse.
In this article, I’m going to walk through four things that the conventional medical system consistently gets wrong about diverticulitis.
Here is a video we made; there is also a written version underneath.
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