It can certainly feel as though food intolerances are becoming more common.
More people are avoiding lactose, gluten, certain fermentable carbohydrates, additives or other foods because they notice digestive symptoms after eating them. Supermarket shelves have expanded to accommodate lactose-free, gluten-free and other specialist foods, while conversations about bloating, digestive discomfort and food triggers are now far more common than they once were.
But does this mean food intolerance itself is genuinely increasing?
The answer is not completely straightforward. In some cases, rates may be changing. In others, we are simply better at recognising symptoms that once went unexplained. Self-diagnosis, changing dietary habits and greater public awareness also influence what we see.
First, What Is a Food Intolerance?
Food intolerance is different from a food allergy.
A food allergy involves the immune system and can, in some cases, cause a rapid and potentially serious reaction. Food intolerance usually involves difficulty digesting or tolerating a particular food or component of food and is more likely to cause symptoms such as bloating, abdominal pain, gas, diarrhoea or digestive discomfort.
Lactose intolerance is one of the clearest examples. It occurs when the body does not produce enough lactase, the enzyme needed to properly digest lactose in dairy foods.
Coeliac disease is different again. It is an autoimmune condition triggered by gluten and requires medical diagnosis and lifelong strict avoidance of gluten.
That distinction matters, because the causes, risks and management of these conditions are not the same.
We Are Better at Recognising Digestive Problems
One reason food intolerances appear more common is simply that people are more aware of them.
Symptoms such as chronic bloating, diarrhoea or abdominal discomfort may once have been dismissed as a “sensitive stomach”. Today, people are more likely to seek help, keep track of symptoms and investigate whether particular foods are involved.
Healthcare professionals also have better-established ways of investigating conditions such as lactose intolerance, coeliac disease and disorders such as irritable bowel syndrome.
That does not necessarily mean every reported intolerance represents a newly emerging condition. Some may simply have gone undiagnosed in previous generations.
Our Diets Have Changed
Modern diets are also very different from those eaten several generations ago.
Many people now eat a greater proportion of highly processed foods and fewer whole foods rich in fibre and plant diversity. Others may suddenly increase fibre, legumes or fermented foods in an attempt to eat more healthily and then experience digestive discomfort because their gut is not accustomed to them.
That does not mean these foods are unhealthy or that they have caused an intolerance.
Sometimes the issue is quantity, frequency or individual tolerance.
Large amounts of certain fermentable carbohydrates, for example, can trigger bloating and digestive symptoms in some people, particularly those with irritable bowel syndrome.
The important point is that digestive symptoms do not automatically mean a food is damaging the body.
The Gut Microbiome May Play a Role
Our gut contains a large community of microorganisms that interact with the food we eat and with many aspects of digestive health.
Diet, illness, antibiotics and other environmental factors can influence the composition of this microbiome. Researchers are increasingly interested in whether differences in gut bacteria may help explain why some people tolerate particular foods differently from others.
However, this is still an evolving area of research.
It is too simplistic to say that an “unbalanced microbiome” directly causes food intolerance. The relationship is likely to be much more complex, and we are still learning how significant it is for different digestive conditions.
Genetics Matter Too
Some food intolerances have a clear genetic component.
Lactose intolerance is a good example. The ability to continue producing lactase into adulthood varies significantly between populations and is strongly influenced by genetics.
Coeliac disease also has a genetic component, although having the relevant genes does not automatically mean someone will develop the disease.
For other food intolerances, genetics may be only one piece of a much larger puzzle involving digestion, gut function, medical conditions and individual sensitivity.
Sometimes the Problem Is Something Else
It is easy to blame a single food when digestive symptoms appear after eating, but food is not always the whole explanation.
Stress, gastrointestinal infections, medications, hormonal changes, constipation, irritable bowel syndrome and other digestive conditions can all affect how comfortable we feel after eating.
Even portion size can matter.
Someone may tolerate a small amount of a particular food perfectly well but experience symptoms after eating a much larger quantity.
This is one reason very restrictive elimination diets can sometimes create more problems than they solve, particularly when foods are removed without a clear reason.
Be Careful With Self-Diagnosis
If you regularly experience symptoms after eating, keeping a simple food and symptom diary can be useful.
Look for patterns rather than blaming the last food you ate.
And if symptoms are frequent, severe or worsening — particularly if you experience unexplained weight loss, blood in the stool, persistent diarrhoea, anaemia or significant pain — it is important to speak with your GP or another qualified healthcare professional.
Coeliac disease in particular should ideally be tested before removing gluten, because avoiding gluten beforehand can interfere with diagnostic testing.
The Bigger Picture
Food intolerances probably appear more common for a combination of reasons.
We are better at recognising digestive symptoms, people are more willing to talk about them, diagnostic methods have improved, and our diets and lifestyles have changed considerably.
At the same time, digestive tolerance is highly individual.
A food that causes discomfort for one person may be perfectly well tolerated by another — and a food that causes symptoms today may not necessarily need to be avoided forever.
Rather than assuming every uncomfortable reaction represents a permanent intolerance, it can be more helpful to understand what is happening, how much of a food you tolerate, and whether another underlying issue may be contributing.
Food should not become something to fear.
The goal is to find the broadest, most varied diet you can comfortably enjoy.