IBS Diet: A Registered Dietitian’s Guide to Eating for a Calmer Gut
Eating for a calmer gut: where do you start?
If you live with irritable bowel syndrome (IBS), you’ll know how frustrating digestive symptoms can be. Bloating after meals, abdominal discomfort, constipation, diarrhoea or suddenly needing to find a toilet can affect everything from your working day to social plans.
You may have already tried cutting out certain foods, searching online for answers or wondering whether something in your diet is making your symptoms worse. But with so much conflicting advice about gut health, it can be difficult to know what to trust.
As a registered dietitian, my advice is to start with the basics rather than cutting out lots of foods at once. There is no single IBS diet that works for everyone. The most helpful approach is one that considers your symptoms, food preferences, lifestyle and nutritional needs.
At Wimbledon Medical Service, we understand that digestive symptoms can affect your confidence and quality of life. In this guide, we’ll explore practical ways to manage IBS through diet, understand the low FODMAP diet and support your gut health without unnecessary restrictions.
What is IBS?
Irritable bowel syndrome is a common condition affecting the digestive system. Symptoms can include:
Abdominal pain or cramping.
Bloating and excessive wind.
Constipation, diarrhoea or alternating between the two.
Urgency or feeling that you haven’t completely emptied your bowels.
Symptoms can vary from day to day and may be affected by food, stress, sleep, hormones and changes in routine.
IBS is a disorder of gut - brain interaction. Communication between the brain and digestive system, alongside factors such as gut sensitivity and bowel movement patterns, can contribute to symptoms. IBS is not simply caused by eating the wrong foods.
If you think you may have IBS but haven’t been assessed, speak to one of our GPs. Other conditions, including coeliac disease and inflammatory bowel disease, can cause similar symptoms and may need to be ruled out.
What is IBS?
Irritable bowel syndrome is a common condition affecting the digestive system. Symptoms can include:
Abdominal pain or cramping.
Bloating and excessive wind.
Constipation, diarrhoea or alternating between the two.
Urgency or feeling that you haven’t completely emptied your bowels.
Symptoms can vary from day to day and may be affected by food, stress, sleep, hormones and changes in routine.
IBS is a disorder of gut brain interaction. Communication between the brain and digestive system, alongside factors such as gut sensitivity and bowel movement patterns, can contribute to symptoms. IBS is not simply caused by eating the wrong foods.
If you think you may have IBS but haven’t been assessed, speak to one of our GPs. Other conditions, including coeliac disease and inflammatory bowel disease, can cause similar symptoms and may need to be ruled out.
Start with the basics: everyday eating habits
Before trying a specialist diet, it is important to look at your symptoms and usual eating pattern. Small changes can sometimes make a meaningful difference.
Eat regularly: Avoid skipping meals, take your time eating and consider smaller meals if large portions trigger symptoms.
Drink enough fluid: NICE suggests around eight cups of fluid daily, particularly water or other non-caffeinated drinks. You may need more if active or have vasomotor symptoms like hot flushes.
Review caffeine, alcohol and fizzy drinks: These may aggravate symptoms for some people, but you do not necessarily need to avoid them completely.
Keep a symptom diary: Record meals, bowel habits and symptoms for a week or two. Look for consistent patterns rather than assuming the last food you ate caused the problem.
If you have been advised to restrict fluids because of a medical condition, follow your healthcare professional’s advice.
Understanding the low FODMAP diet
If basic dietary and lifestyle changes have not helped enough, you may have heard about the low FODMAP diet.
FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. These are types of short-chain carbohydrates found in everyday foods.
Some FODMAPs are poorly absorbed in the small intestine. They can draw water into the bowel and are fermented by gut bacteria, producing gas. In people with IBS, this may contribute to bloating, abdominal discomfort and changes in bowel habits.
A low FODMAP diet reduces certain FODMAPs for a short period to see whether symptoms improve. It can help some people with IBS, but it does not work for everyone.
What foods contain FODMAPs?
Examples include onions, garlic, some wheat-based foods, certain fruits, some lactose-containing dairy products, particular beans and lentils, and foods containing polyol sweeteners.
Lower-FODMAP alternatives may include oats, rice, potatoes, quinoa, carrots, courgettes, eggs, plain meat and fish, lactose-free milk and suitable portions of fruits such as kiwi or oranges. Portion sizes matter, so a food is not necessarily unsuitable simply because it contains FODMAPs.
How does the low FODMAP diet work?
The diet has three stages:
Short-term restriction: Swap higher-FODMAP foods for suitable alternatives for a limited period, commonly around two to six weeks.
Reintroduction: If symptoms improve, systematically reintroduce different FODMAP groups to identify what you tolerate.
Personalisation: Build the widest possible diet around your individual tolerance, restricting only foods and quantities that consistently trigger symptoms.
Should you cut out gluten, dairy or other foods?
It is tempting to remove several food groups when your digestion feels unpredictable. However, restrictive diets can make eating more stressful and reduce the variety of nutrients you get. Unnecessary restrictions may also make it harder to include a wide range of fibre-containing foods and exacerbate symptoms.
You do not automatically need to follow a gluten-free or dairy-free diet to manage IBS. If lactose triggers your symptoms, lactose-free alternatives may help, while some people can tolerate certain dairy products.
Important: If coeliac disease has not been ruled out, speak to your GP before removing gluten. Coeliac blood tests are most reliable when you are still eating gluten.
Are probiotics worth trying?
Probiotics are often marketed for gut health, but evidence for their effectiveness in IBS is mixed evidence is based on specific strains. NICE advises that if you choose to try a probiotic, you should take it at the manufacturer’s recommended dose for at least four weeks while monitoring your symptoms.
Fibre and IBS: are you eating too much or too little?
Fibre can be confusing when you have IBS. You may have been advised to eat more for constipation, yet find that wholegrains or bran make your bloating worse.
Soluble fibre, found in oats and supplements such as ispaghula husk, may help some people with IBS. Insoluble fibre, including wheat bran, can aggravate symptoms for some people.
Rather than automatically adding lots of bran or fibre supplements, review your current intake and make gradual changes. Drink enough fluid and allow time to assess the effect.
Your fibre needs may differ depending on whether you experience constipation, diarrhoea or alternating bowel habits. A dietitian can help tailor your intake to your symptoms.
Gut health: what does it really mean?
You may see advice online about healing your gut, balancing your microbiome or taking supplements to improve digestion. Some of these ideas are based on emerging research, but many commercial claims go beyond the available evidence.
A varied diet containing tolerated sources of fibre can help support your gut microbiome. If your symptoms allow, include a range of plant foods over time, such as vegetables, fruit, oats, wholegrains, nuts, seeds and pulses.
You do not need to force yourself to eat foods that consistently cause significant symptoms. Gut health is also about more than food: regular movement, sleep, stress management and appropriate medical care all contribute to digestive wellbeing.
Be cautious of supplements or programmes that promise to cure IBS, detox your gut or permanently repair your digestion.
Can stress make IBS worse?
IBS is not “all in your head”, but the gut and brain communicate closely. Stress, anxiety and poor sleep can influence gut sensitivity and bowel function, potentially making symptoms more noticeable.
Gentle movement, regular sleep and relaxation techniques may help some people. If IBS significantly affects your quality of life, your GP can discuss additional options, including psychological therapies such as gut-directed hypnotherapy or cognitive behavioural therapy.
Dietary changes, medication and psychological support can sometimes work best together.
When should you seek medical advice?
Although IBS is common, it is important not to assume every digestive symptom is caused by IBS.
Arrange a GP appointment if you have persistent bloating, abdominal pain or a change in bowel habits, particularly if symptoms are new or you have not previously been assessed.
Seek prompt medical advice if you notice:
Blood in your poo or bleeding from your bottom.
Unexplained weight loss.
A persistent lump or swelling in your abdomen.
Symptoms that are progressively worsening or substantially different from your usual pattern.
Your GP may recommend tests to check for conditions such as coeliac disease, anaemia or inflammatory bowel disease. If you have severe or sudden abdominal pain, heavy bleeding or feel acutely unwell, seek urgent medical assessment.
Supporting your gut health at Wimbledon Medical Service
Living with IBS can be exhausting, especially when symptoms are unpredictable or you feel you have to plan every meal around your digestion.
The good news is that there are several ways to manage IBS, and you do not necessarily need to follow a highly restrictive diet. Understanding your symptoms, making realistic changes and getting the right support can help you feel more confident around food.
At Wimbledon Medical Service, our GPs can help assess your symptoms, consider whether further investigation is needed and discuss appropriate treatment options. If dietary changes have not helped, support from a registered dietitian with experience in IBS and the low FODMAP diet may help you identify individual triggers while keeping your diet as varied as possible.
If digestive symptoms are affecting your everyday life, contact Wimbledon Medical Service to arrange a consultation and discuss the next steps.
References
National Institute for Health and Care Excellence (NICE). Irritable bowel syndrome in adults: diagnosis and management (CG61).
Monash University. Starting the low FODMAP diet.
Monash University. Practical tips for FODMAP reintroduction.
Whelan K, Martin LD, Staudacher HM, Lomer MCE. The low FODMAP diet in the management of irritable bowel syndrome: an evidence-based review. Journal of Human Nutrition and Dietetics. 2018;31(2):239–255.
Medical disclaimer: This article is intended for general educational purposes and does not replace individual medical advice, diagnosis or treatment. Digestive symptoms can have different causes, and dietary needs vary. Please consult a qualified healthcare professional for advice tailored to your circumstances.