IBS: when food rules keep growing but the symptoms do not stop

For people with bloating, pain, constipation, diarrhoea or unpredictable bowels who have had the tests, tried the diets, and still do not have a clear answer.

Key takeaways

  • IBS is real, but it is not one single cause. The bowel can look normal on tests while its function is still disrupted.
  • Low FODMAP can help, but it is not meant to become your whole life. The goal is reintroduction, personalisation and more freedom.
  • Stress does not mean “it is all in your head”. Gut nerves, motility, immune signalling, mast cells, microbiome changes, sleep and food tolerance can all interact.
  • Persistent gut symptoms usually need a layered plan. Safety first, then suitability, then the right combination of diet, nervous-system work, acupuncture, microbiome support, nutrient support and referral where needed.

This article is for the patient who has already done the sensible things.

You have bloating, pain, constipation, diarrhoea, urgency or unpredictable bowels. You may have seen a doctor, had blood tests, stool samples, an endoscopy, a colonoscopy, or several investigations to make sure nothing dangerous has been missed.

You may have been told everything looks normal. You may have been given an antispasmodic, a laxative, fibre, probiotics, or advice to try the low FODMAP diet.

For a while, some of that may have helped.

But the problem has not fully resolved.

You are still bloated after meals. Your bowels still feel unpredictable. Eating out still feels risky. You may have cut out garlic and onions, then wheat, then dairy, then fermented foods, then anything that seems to trigger you.

Eventually the question is no longer only, “What food should I avoid?”

It becomes:

“Why is my gut reacting this way in the first place?”

That is the gap this article is about.


First, make sure nothing important has been missed

Before going deeper into IBS, this matters: persistent bowel symptoms should be assessed properly.

Coeliac disease, inflammatory bowel disease, microscopic colitis, thyroid dysfunction, deficiencies, infection, structural pathology, and in some women, endometriosis with bowel involvement, all need to be considered where the history fits1–7.

Red flags such as unexplained weight loss, blood in the stool, iron-deficiency anaemia, night-time diarrhoea, a family history of bowel cancer or inflammatory bowel disease, or new bowel symptoms after the age of fifty should not be ignored.

If those checks are reassuring and the symptoms continue, the next step is not to keep guessing. It is to understand the pattern properly.


IBS is real, but it is not one single cause

IBS is a recognised disorder of gut-brain interaction. It usually involves abdominal pain or discomfort with changes in bowel habit, when red flags and other realistic causes have been considered.

This is why IBS often does not appear on standard blood tests, scans, endoscopy or colonoscopy. The structure may look reassuring, but the function can still be disrupted.

That diagnosis can be useful. But it does not mean every person with IBS has the same problem.

One person’s symptoms may have started after food poisoning or gastroenteritis8. Another may have worsened after repeated antibiotics. Another may have a gut that becomes more reactive during stress, poor sleep, hormonal changes or long periods of anxiety. In some women, bowel symptoms that move strongly with the cycle may point toward endometriosis as part of the picture.

Other conditions can also look like IBS or overlap with it, but need a different route. Bile acid diarrhoea, small intestinal bacterial overgrowth, pelvic floor dysfunction, inflammatory bowel disease, coeliac disease, microscopic colitis and endometriosis are examples9.

The job is to ask: what is actually driving this person’s pattern, and what should come first?


The food-rule spiral

At first, cutting certain foods helps.

Then the rules grow.

Garlic and onions → wheat → dairy → fermented foods → raw foods → cold foods → eating out → social life.

The list gets longer. The bloating does not stop. The fatigue worsens. The person becomes more careful, but not more free.

The low FODMAP diet has good evidence behind it and can reduce bloating, pain and bowel-pattern symptoms in many people with IBS10–12. But it is meant to be used properly: short elimination, careful reintroduction, then personalisation around what you can tolerate, what you cannot tolerate yet, and what can be rebuilt over time.

A food diary can help, but only if it leads to understanding rather than fear. The point is to identify patterns, reduce the immediate load, and rebuild confidence and tolerance.

If you have been living on restriction for months or years, the question should be “why has my gut become so reactive, and how do we rebuild tolerance?”

The aim is not more rules. It is more precision, and then more freedom.


Why the same food can feel different on different days

One of the most confusing things patients tell me is this:

“I ate the same meal last week and I was fine. This week it ruined me.”

That does not automatically mean the food is harmless. It also does not automatically mean the food is the whole problem.

IBS is strongly connected to the gut-brain axis: the communication between the gut, nervous system, immune system, microbiome and brain13–14.

The gut can become hypersensitive. The nerves in the digestive tract may respond more strongly to stretching, gas, stool, fermentation or normal digestive movement. The muscles of the gut may move too quickly, too slowly or in an uncoordinated way. This can contribute to pain, bloating, diarrhoea or constipation.

Stress biology can influence gut movement, gut permeability, immune activity and microbial balance15. Mast cells and histamine-related signalling may also contribute to nerve sensitivity and pain in some patients16–18.

For many people, the gut is not reacting only to food. It is reacting through the state of the nervous system receiving that food.

That is why IBS can often come with upper abdominal tension, fatigue, poor sleep, or a constant low-grade feeling of being on edge. The gut is not always a separate problem. Sometimes it is one expression of a wider pattern.


What Chinese medicine and Ayurveda add

This is where older medical systems become useful, if they are used carefully.

Ayurveda and Chinese medicine have always treated digestion as part of the whole person.

Ayurveda places digestion at the centre of health. It looks at appetite, bowel rhythm, food tolerance, energy, sleep, emotional state, constitution, and whether digestion is weak, erratic, overheated, depleted or overloaded. Early clinical research into whole-system Ayurveda for IBS is promising 19–20.

Chinese medicine has also paid close attention to the link between digestion and emotional strain for thousands of years. In modern language, we might talk about the enteric nervous system, vagus nerve, autonomic regulation and gut-brain axis. In Chinese medicine language, we might talk about how stress, frustration, sadness or chronic tension disrupt the movement and transformation of food and fluids. This is why bloating, abdominal tension, constipation, diarrhoea, reflux, nausea or urgency are not always treated as isolated gut problems. They may also be signs that the digestive system and nervous system are no longer communicating smoothly.

Evidence for acupuncture in trials and reviews for example is starting to suggest improvements in symptom severity, abdominal pain, stool pattern or quality of life. This in my view can be one useful tool inside a wider plan, to work on both sides of this loop when IBS clearly worsens with stress, anxiety, poor sleep, tension or feeling constantly on edge 21–23.


What I look for in clinic

I am not only asking, “What foods trigger you?”

I want to know:

  • when the bloating starts
  • whether the bowels are loose, slow, urgent, incomplete or alternating
  • whether symptoms began after food poisoning, antibiotics, travel, viral illness, stress, hormonal change or a new medication
  • whether symptoms worsen before the period
  • whether sleep, anxiety, breath, jaw tension or upper abdominal tightness are part of the same picture
  • whether the diet is highly processed, low in fibre, irregular, rushed or dominated by caffeine, alcohol, sugar or convenience foods
  • whether there are signs of nutritional depletion after long-term restriction
  • what has already been ruled out
  • what has already been tried
  • what helped briefly, and what never held

Together, these details show the pattern.

This is also where Ayurveda and Chinese medicine change the quality of the plan. I am not just asking whether a food is high FODMAP. I am asking whether that food is right for this person’s digestive strength, constitution, current stress state, bowel pattern and overall physiology.

A cold raw salad may be healthy on paper and completely wrong for a depleted, tense, bloated digestive system. Fermented foods may help one person and flare another. Fibre may help constipation in one patient and worsen bloating in another.

That is why the goal is a personalised plan that fits the person.


What a better plan usually needs

No single therapy works for everyone with IBS. Most people need the right combination of changes, in the right order.

First: safety. Has anything important been missed?

Second: the gut pattern. Is this mainly motility, sensitivity, food reactivity, post-infectious change, nervous-system activation, hormonal rhythm, microbiome disruption, digestive weakness, nutrient depletion, or a mixture?

Third: reset. Reduce gut load. Support digestion. Calm the nervous system. Address obvious deficiencies. Stabilise rhythm. Rebuild confidence around food.

This may include personalised diet, acupuncture for gut symptoms, electroacupuncture, scalp acupuncture, breath work, nervous-system regulation, microbiome support, nutrient support, movement, sleep work, or referral for further testing when needed.

The point is to stop guessing and build the plan around what is actually happening.

This work usually sits inside my wider integrative medicine practice.

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Frequently asked questions

Should I go gluten-free? First, make sure coeliac disease has been properly excluded while you are still eating gluten. If coeliac disease is excluded and you genuinely feel better without wheat, that is useful information. In some people this may be related to FODMAPs rather than gluten itself.

Are probiotics worth it? Sometimes, but “take a probiotic” is not a plan. The strain, dose, timing and pattern matter. Some people improve. Some people worsen.

Is IBS linked to anxiety? Yes, in both directions. Anxiety and depression are reported more commonly in people with IBS than in healthy controls 24. Stress and anxiety tied to nervous-system dysregulation can worsen gut symptoms through the gut-brain axis. Persistent gut symptoms can also create anxiety because the body feels unpredictable. Treating both together often makes more sense than separating them.

Is stress the cause of IBS? Stress can worsen IBS and keep the gut reactive, but it is rarely the whole explanation. Food tolerance, motility, visceral sensitivity, microbiome changes, infections, hormones, sleep, medications and nervous-system state can all matter. My approach targets several of these layers rather than treating stress or diet in isolation.


Medical disclaimer

This article is for educational purposes. It is not a substitute for individual medical assessment, diagnosis, or treatment. Do not alter or stop medication, or begin new treatment, based on this article alone. Consult a qualified clinician who can evaluate your specific situation. If you have red-flag symptoms such as unexplained weight loss, rectal bleeding, iron-deficiency anaemia, night-time diarrhoea, persistent vomiting, or new severe abdominal pain, seek medical assessment promptly.

Written and medically reviewed by Dr Shehan Wijesingha. Last reviewed April 2026.

References
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