10 Common Mistakes That Make Irritable Bowel Syndrome Worse

IBS: a condition more widespread than you might think

Irritable bowel syndrome (IBS) affects around 1 in 20 people worldwide. Recurring abdominal pain, bloating, diarrhoea, constipation, or a combination of both — the symptoms are real, debilitating, and yet frequently misunderstood.

This functional disorder involves a complex interplay between intestinal motility, visceral sensitivity, the gut microbiome, the intestinal barrier, and the brain. It is not "all in your head", but it is not purely a dietary issue either. And that is precisely where many people go wrong: in trying to do the right thing, they sometimes make their situation worse.

Here are the 10 most common mistakes identified by current medical guidelines (ACG 2021, AGA 2022–2023).

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The 10 mistakes to avoid

1. Eating too many ultra-processed foods

Ultra-processed products are often low in quality fibre and high in additives, emulsifiers, and fermentable sugars. They promote low-grade inflammation and can disrupt the gut microbiome, worsening digestive symptoms in sensitive individuals.

2. Cutting out all fibre

Out of fear of bloating, some people eliminate fibre entirely. This is a mistake. Soluble fibre — particularly psyllium — is recommended as a first-line intervention by the ACG to improve regularity and reduce certain symptoms. It is primarily insoluble fibre (wheat bran, certain skins) that can worsen pain in IBS patients.

3. Increasing fibre intake too quickly

Conversely, introducing large amounts of fibre over a short period stimulates colonic fermentation and gas production. The recommended approach is a gradual increase, alongside adequate hydration, favouring better-tolerated fibre sources.

4. Unknowingly consuming high amounts of FODMAPs

FODMAPs are fermentable, poorly absorbed carbohydrates — found in garlic, onion, wheat, certain fruits, and pulses — that increase water in the intestine and gas production. In a significant proportion of IBS patients, reducing FODMAPs noticeably improves symptoms. However, this diet must be supervised and time-limited, with a structured reintroduction phase to identify your personal triggers. Followed for too long without guidance, it can reduce both dietary variety and microbial diversity.

5. Drinking fizzy drinks and heavily sweetened juices

Beverages high in fructose or polyols (sorbitol, mannitol) have an osmotic effect in the intestine and encourage fermentation. The result: diarrhoea, gas, and cramping. These sugars are particularly problematic in diarrhoea-predominant IBS.

6. Trusting "sugar-free" products without reading the label

Chewing gum, sweets, and "light" products often contain polyols such as xylitol or sorbitol. Even in small quantities, these sweeteners can trigger significant digestive symptoms in people with IBS.

7. Failing to identify your own food triggers

IBS is a highly heterogeneous condition: a food that one person tolerates perfectly may trigger a flare-up in another. Current guidelines recommend keeping a food and symptom diary and following a structured approach — ideally with a registered dietitian — rather than making multiple empirical restrictions that impoverish the diet without resolving the problem.

8. Neglecting stress and sleep

The gut–brain axis is central to IBS. Chronic stress, anxiety, and poor sleep amplify pain, faecal urgency, and bowel disturbances. Both the ACG and AGA acknowledge the effectiveness of cognitive behavioural therapy and gut-directed hypnotherapy in reducing symptoms. Managing your stress is also a way of caring for your gut.

9. Taking antibiotics without clear medical justification

Antibiotics can profoundly and lastingly disrupt the gut microbiome. In some patients, this disruption may precede or worsen persistent digestive symptoms. Antibiotics are not a treatment for IBS and should be reserved for medically justified situations.

10. Remaining sedentary

Regular physical activity improves intestinal motility, reduces stress, and contributes to overall wellbeing. In IBS, it can relieve constipation and improve symptom perception. Current guidelines encourage regular, adapted activity — even at a moderate level.

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Key takeaways

IBS cannot be managed with a universal list of forbidden foods. The best scientific evidence points towards an individualised, gradual, and multimodal approach: identifying your personal triggers, supporting your microbiome with suitable fibre, addressing stress, and staying active.

If you recognise several of these mistakes in your daily life, there is no need to panic — each small adjustment can make a genuine difference to your symptoms.

Key references: ACG Clinical Guidelines 2021; AGA Guidelines 2022–2023; Gibson & Shepherd, Gastroenterology (FODMAPs); global IBS prevalence analyses (Sperber et al., Gastroenterology 2021).