The Best Diet for IBS: What Actually Works (and What to Avoid) – Dietitian Guide

What is the best diet for IBS? (Quick Summary)
The best diet for IBS is a personalised approach rather than a one-size-fits-all plan. Most people benefit from regular meals, balanced nutrition, and identifying individual trigger foods. A short-term low FODMAP diet, guided by a dietitian, can help pinpoint specific triggers, but it is not a long-term solution. Managing IBS effectively also involves lifestyle factors such as stress, sleep, and eating habits, not just food choices.

If you’ve been told you have IBS, you’ve probably already gone down the Google rabbit hole.

Cut out dairy.
Go gluten-free.
Try this supplement.
Avoid that food.

Yet… you’re still bloated. Still uncomfortable. Still second-guessing every meal.

If you’re sitting there thinking:

• “I feel like I’ve tried everything”
• “Why is this still happening?”
• “What am I actually supposed to eat?”

Please know you’re not alone, as a Dietitian and someone who struggles with gut issues I know who frustrating this can be.

IBS is one of the most common conditions I see in clinic, and one of the most frustrating to live with. Not just because of the symptoms, but because of how confusing the advice can be.

The good news is that diet can absolutely help, however not in the way social media often suggests.

In this article, I’ll walk you through:

• What the best diet for IBS actually looks like
• When the low FODMAP diet can help (and when it doesn’t)
• What to eat, what to be careful with, and what really matters

And most importantly, how to start finding an approach that works for your body.

What is the best diet for IBS?

The best diet for IBS is a personalised approach, there isn’t one single ‘IBS diet’ that works for everyone. For many people, this starts with simple lifestyle changes such as regular meals and balanced nutrition. If symptoms persist, a short-term low FODMAP diet guided by a dietitian can help identify specific triggers.

The low FODMAP diet is often highlighted as a leading dietary approach for IBS, with success rates ranging from 50-80%. However, it is a challenging diet to undertake without the guidance of a dietitian.

What Is the Low FODMAP Diet?

FODMAP is an acronym for a group of fermentable carbohydrates that are not fully digested or absorbed in the small intestine. When they reach the large intestine, they are fermented by gut bacteria, leading to gas production, bloating, and diarrhoea.

Here’s what FODMAP stands for:

Fermentable: Foods that are not fully digested or absorbed and ferment in the large bowel, producing gas and drawing in water, which can lead to bloating, diarrhoea, and pain.
Oligosaccharides: Fructans and galacto-oligosaccharides, which are poorly absorbed by everyone as we lack the enzymes to digest them.
Disaccharides: Lactose, a sugar found in animal milk.
Monosaccharides: Fructose, which in excess can be difficult to absorb.
Polyols: Sugar alcohols found in some fruits, vegetables, and artificial sweeteners.

Important Considerations About the Low FODMAP Diet

• It’s not a long-term solution: The low FODMAP diet is a short-term strategy used to reduce symptoms before moving on to a reintroduction phase to identify personal triggers and tolerance levels.
• It’s about reducing, not eliminating: The goal is to lower FODMAP intake, not cut it out entirely, as these foods support gut health.
• It’s not suitable for everyone: The diet is complex to follow and may worsen symptoms for those with constipation-dominant IBS (IBS-C). To get the best results you should follow it under the guidance of a Dietitian. If you are struggling with constipation you may find my blog article on constipation helpful: https://inspiritdiet.co.uk/what-helps-constipation-after-50/
• Tolerance varies: Even if certain FODMAPs cause symptoms, you may still tolerate small amounts, such as a slice of regular bread without issues.
• It’s not the first-line approach: Other dietary and lifestyle adjustments should be tried before considering the low FODMAP diet.

Now we’ve looked at the low FODMAP diet, let’s take a step back and look at some other areas that can make a real difference. You may also want to have a look at the NICE guidelines for advice.

What to Eat with IBS (Without Overcomplicating It)

Rather than focusing on what to cut out, it can be helpful to start with what to include.

In clinic, I often see people who have removed so many foods that their diet becomes very limited, which can actually make symptoms worse over time.

Some gentle starting points:

• Regular meals across the day
• Oats, rice, potatoes and other easy-to-digest carbohydrates
• Well-tolerated fruits such as bananas or berries
• Protein sources like eggs, chicken, fish, yoghurt
• Fluids spread evenly across the day

It doesn’t need to be perfect.
It just needs to be consistent.

Foods That Can Trigger IBS Symptoms (But Aren’t “Bad”)

Certain foods can trigger symptoms, but that doesn’t mean they are harmful or need to be avoided forever.

Common triggers include:

• Large amounts of caffeine
• Alcohol
• High-fat meals
• Highly processed foods
• Certain high FODMAP foods (for some people)

The key is not cutting everything out.

It’s understanding your personal tolerance.

Common Mistakes I See with IBS Diets

• Cutting out too many foods
• Starting low FODMAP without guidance
• Skipping meals
• Ignoring stress
• Expecting quick fixes

One of my clients described it perfectly:

“Three sessions made an enormous difference – far less pain, bloating and unpredictability. Those symptom-free days feel life-changing.”

This is what’s possible with the right support and often much simpler than people expect

Other factors that can affect your IBS symptoms

Chew Your Food Well to Aid Digestion and Reduce Bloating

Digestion begins in the mouth, where the enzyme amylase starts breaking down carbohydrates. Chewing food thoroughly (about 20 times per mouthful) gives amylase time to work and helps reduce bloating by minimising swallowed air. If bloating is one of your main issues then check out my blog Is bloating just a normal part of aging?

The Role of Caffeine in IBS

Some people with IBS find that coffee worsens diarrhoea due to its gut-stimulating effects. Caffeine can also increase cortisol levels, potentially heightening feelings of anxiety. Additionally, as sleep disturbances are common in IBS, it’s worth noting that caffeine can stay in your system for up to 10 hours. If you rely on an afternoon coffee but struggle to sleep, you might want to reconsider your intake.

Eating Regularly Can Help Manage IBS Symptoms

A common misconception is that fasting or skipping meals helps diarrhoea by reducing gut activity. However, research shows that eating three regular meals per day is associated with fewer symptoms compared to irregular eating patterns. Long gaps between meals can also lead to eating too quickly or consuming large portions, both of which can worsen bloating and urgent bowel movements.

Fluid in IBS

You should be drinking 8 cups of liquid per day, it doesn’t have to just be water, all fluids count, although it is worthwhile remembering the advice about caffeine above. This is particularly important if you have IBS-C (constipation dominant).
You also need a good fluid intake if you are looking to increase your fibre intake as without enough fluid your poo can become harder and difficult to pass.

Alcohol and IBS

Alcohol is a known gut irritant, even for those without IBS. Here are some practical tips:
• Avoid drinking on an empty stomach.
• Alternate alcoholic drinks with non-alcoholic ones.
• Be mindful of fizzy mixers, as they can worsen bloating.
• If opting for mocktails, be cautious of high-fructose ingredients like fruit juices and syrups, which can trigger symptoms.

Managing IBS can feel overwhelming, but small, strategic changes to your diet can make a big difference. While the low FODMAP diet can be an effective tool for symptom relief, it’s not a long-term solution and isn’t necessary for everyone. Simple steps such as chewing your food well, eating regular meals, and being mindful of triggers like caffeine and alcohol can also help improve gut health.

What a Simple IBS-Friendly Day Might Look Like

This doesn’t need to be complicated.

A simple example could look like:

• Breakfast: Porridge with blueberries
• Lunch: Chicken sandwich on sourdough with tangarines
• Dinner: Salmon, potatoes and carrots
• Snacks: Plain crisps, popcorn, oatcakes, peanut butter

Simple. Balanced. Manageable.

When Diet Alone Isn’t Enough

If you’ve read this and thought:

“I’ve tried some of this… but I still don’t feel better”

Please don’t assume this is just something you have to live with.

IBS is rarely about one single food.
It’s usually a combination of:

• Diet
• Stress
• Routine
• Gut sensitivity

And this is exactly what I help my clients work through.

Inside my Gut R.E.S.E.T Method, we take a structured, personalised approach to:

• Identify your specific triggers
• Reintroduce foods safely
• Build a way of eating that feels manageable and sustainable

So you can get to a point where:

You eat without overthinking
You go out without worrying
And your gut feels more predictable again

You don’t need to keep second-guessing every meal or planning your life around your gut. If that’s what you’re looking for, you can find more details here

If you have enjoyed this blog post why not check out my other IBS blog post – How to relieve IBS symptoms fast without changing your diet.  Click here to read it.

Fiona Brannigan, BSc (Hons) Human Nutrition & Dietetics, HCPC-Registered Dietitian, Full member of the British Dietetic Association
Fiona Brannigan is a UK-registered dietitian and founder of Inspirit Nutrition & Dietetic Consultancy, based in Ayrshire and working with clients across the UK. With over 25 years of experience, including more than two decades in the NHS,  Fiona has supported thousands of people to improve their health through nutrition.

Her expertise spans gut health, menopause nutrition, digestive disorders, neurological conditions, and rehabilitation following illness. Fiona is particularly passionate about helping adults aged 50+ regain confidence and control over their gut health, manage symptoms such as bloating, constipation, and diarrhoea, and enjoy food without fear or discomfort.

Fiona is regulated by the Health and Care Professions Council (HCPC) and is a member of the British Dietetic Association (BDA). She offers one-to-one consultations online and in person, using evidence-based nutrition and personalised support to help people feel their best at every stage of life.

Book a free discovery call to discuss your gut health goals or learn more about Fiona’s work