Low FODMAP diet for SIBO

The Low FODMAP diet reduces fermentable carbs that fuel SIBO bacteria, easing bloating and gas. While it helps manage symptoms, it’s not a cure. IBS Clinics provides hydrogen breath testing and practitioner-led support to ensure safe, personalised, and effective treatment. For more information on what to expect when budgeting for SIBO tests, take a look at our article SIBO Test UK Cost.

Managing Small Intestinal Bacterial Overgrowth (SIBO) often involves more than just medication, as what you eat plays a crucial role in how your gut feels day to day. One dietary approach that has gained attention is the Low FODMAP diet, designed to reduce certain fermentable carbohydrates that feed bacteria in the small intestine and trigger symptoms like bloating, gas, and abdominal discomfort.

For some people, following a Low FODMAP plan can bring noticeable relief. But while the diet can help manage symptoms, it isn’t a cure for SIBO, and it’s not always easy to follow without guidance. A functional medicine approach looks at the bigger picture of how to treat SIBO at home, using the Low FODMAP diet as a tool while also addressing the underlying causes of bacterial overgrowth and supporting overall gut health.

In this article, we’ll explore how the Low FODMAP diet works, why it can help with SIBO, its limitations, and why working with a functional medicine practitioner can make all the difference in achieving lasting relief.

Understanding SIBO and the Role of Diet

What Small Intestinal Bacterial Overgrowth is

Small Intestinal Bacterial Overgrowth, or SIBO, occurs when too many bacteria grow in the small intestine – a part of the digestive tract that normally has relatively low bacterial levels compared to the large intestine. This imbalance can interfere with digestion and nutrient absorption, leading to symptoms such as bloating, excessive gas, abdominal discomfort, diarrhoea, or constipation. Because these symptoms overlap with conditions like Irritable Bowel Syndrome (IBS), SIBO often goes undiagnosed without specific testing such as a hydrogen breath test.

Why diet plays such an important role in managing symptoms

What you eat directly influences SIBO symptoms, because the bacteria in the small intestine ferment certain types of carbohydrates. This fermentation produces gas, leading to bloating, discomfort, and changes in bowel movements. Adjusting the diet can help reduce these fermentable foods, starving the bacteria that are driving symptoms and providing welcome relief. However, diet alone does not clear the overgrowth. That’s why dietary changes, such as the Low FODMAP diet, are best used as part of a wider treatment plan designed with professional support.

What Is the Low FODMAP Diet?

How the diet works

The Low FODMAP diet was developed by researchers at Monash University to help people manage digestive symptoms such as bloating, gas, abdominal pain, and altered bowel habits [1]. FODMAPs (Fermentable Oligo-, Di-, Mono-saccharides And Polyols) are specific types of carbohydrates that are poorly absorbed in the small intestine. In people with SIBO, these carbohydrates become fuel for bacterial fermentation, which produces gas and triggers discomfort.

The diet works by reducing foods high in FODMAPs for a limited period of time (usually 4–8 weeks), followed by a careful reintroduction phase to identify individual triggers.

Foods typically restricted and allowed

During the elimination phase, foods high in FODMAPs are reduced or avoided. Once symptoms improve, foods are slowly reintroduced to determine which are best tolerated.

Restricted foods include many high-FODMAP items such as wheat, rye, onions, garlic, beans, lentils, certain fruits (like apples and pears), and dairy products containing lactose.
Allowed foods include alternatives that are naturally lower in FODMAPs, such as rice, oats, potatoes, carrots, spinach, strawberries, blueberries, bananas, and lactose-free dairy or hard cheeses.

Examples of high- and low-FODMAP foods

High-FODMAP examples: apples, pears, watermelon, onions, garlic, wheat bread, lentils, chickpeas, and milk.
Low-FODMAP examples: strawberries, blueberries, grapes, carrots, courgette, rice, oats, lactose-free yoghurt, and chicken.

The aim is not to restrict these foods forever but to identify which ones specifically trigger symptoms, so a balanced and varied diet can be restored. More information about high and low FODMAP foods can be found on the Monash University website.

Low FODMAP Breakfasts

Porridge made with oats and lactose-free milk, topped with blueberries and a sprinkle of chia seeds
Scrambled eggs on gluten-free toast, served with sautéed spinach and tomatoes
Lactose-free yoghurt with strawberries and a small portion of gluten-free granola

Low FODMAP Lunches

Chicken and rice salad with cucumber, red peppers, carrots, and a lemon-olive oil dressing
Baked potato with lactose-free cheese and chives, served with a green salad
Tuna salad wrap using a gluten-free tortilla with lettuce, cucumber, and a Low FODMAP mayo dressing

Low FODMAP Dinners

Grilled salmon with new potatoes and steamed green beans
Stir-fry with chicken, courgette, red peppers, and rice noodles, flavoured with ginger and sesame oil (avoiding garlic and onion)
Roast chicken with mashed potatoes (lactose-free milk) and roasted carrots and parsnips

Snacks can also be helpful. Options include rice cakes with peanut butter, lactose-free cheese cubes, or a small portion of grapes, which can help keep energy stable without triggering symptoms.

Why the Low FODMAP Diet Helps Some People with SIBO

Although the Low FODMAP diet was originally developed for people with Irritable Bowel Syndrome (IBS) [1], research and clinical experience show it can also benefit those with SIBO, as many IBS sufferers also have SIBO [2].

By reducing fermentable carbohydrates that feed bacteria in the small intestine, the Low FODMAP diet helps to limit bacterial fermentation. This means less gas production, which in turn can ease bloating, cramping, and discomfort. For many, this results in noticeable symptom relief within a few weeks. However, it should be noted that data on using a low FODMAP diet for SIBO are principally based on extensions of the data gathered on IBS, and there is no conclusive link on its efficacy in alleviating SIBO symptoms [2], though it has been established that low FODMAP diets are associated with ‘fewer fermentation products’ when measured on a breath test [2].

The diet doesn’t eliminate the bacterial overgrowth itself, but it can make day-to-day symptoms more manageable and support the gut while other treatments, such as antimicrobials, prokinetics, or targeted supplements, take effect. When used as part of a broader functional medicine plan, the Low FODMAP diet can play a role in helping patients feel better while addressing the root causes of SIBO.

Limitations of the Low FODMAP Diet

Although the Low FODMAP diet can provide welcome relief from bloating, gas, and discomfort, it does not remove the bacterial overgrowth causing the problem. At best, it helps manage symptoms while other treatments such as antibiotics, herbal antimicrobials, or prokinetics address the root issue. This is why it’s best used as part of a wider treatment plan, rather than as a standalone solution.

Risks of following it long-term without guidance

The Low FODMAP diet is designed to be temporary. Prolonged restriction can reduce the diversity of your gut microbiome, which may actually make digestive health worse over time [3]. Without professional support, people often stay in the elimination phase far longer than recommended, leading to frustration, unnecessary restriction, and ongoing anxiety around food.

Potential nutrient deficiencies and the challenge of reintroduction

Because the diet limits a wide range of fruits, vegetables, grains, and dairy, it can easily lead to nutritional gaps if followed long-term. Reintroduction (the stage where foods are gradually added back to identify individual triggers) is often the most challenging part to manage alone. Many people give up at this stage, either staying on an unnecessarily strict diet or reintroducing foods too quickly and triggering symptoms again. Working with a practitioner helps ensure the diet remains balanced and sustainable, while identifying your personal food triggers accurately.

Why Work with a Functional Medicine Practitioner

Tailoring the Low FODMAP Diet to your SIBO type

Not all cases of SIBO are the same. Some people have hydrogen-dominant SIBO, others methane or hydrogen sulphide type, and each can respond differently to dietary changes. A functional medicine practitioner can help adapt the Low FODMAP diet to your SIBO type, ensuring that the foods you include or avoid are matched to your specific needs rather than following a one-size-fits-all approach.

Combining diet with other treatments such as prokinetics and antimicrobials

While the Low FODMAP diet can reduce symptoms, lasting relief requires additional treatment. A practitioner can combine dietary strategies with other interventions such as herbal antimicrobials, antibiotics, or prokinetics to address bacterial overgrowth and reduce the risk of relapse. This integrated approach helps to tackle both the immediate discomfort and the underlying causes.

Monitoring progress and adapting your plan for long-term success

SIBO can be complex, and symptoms often change over time. Regular support sessions with a practitioner ensure your plan is adapted as you improve, helping you move from elimination through reintroduction without unnecessary restriction. This guidance also helps you build a sustainable, balanced diet that supports gut health long after symptoms settle.

Benefits of meal plans, symptom tracking, and practitioner check-ins

Trying to follow the Low FODMAP diet on your own can feel overwhelming. Without clear guidance, it’s easy to stay stuck in the elimination phase too long or to reintroduce foods too quickly, leading to unnecessary restriction or a return of symptoms. Structured support makes the process far smoother, with meal plans, symptom tracking, and professional check-ins helping you stay on track and understand what your body needs.

Introducing our I Can Beat SIBO course

At IBS Clinics, we offer I Can Beat SIBO – a six-module, practitioner-led online programme designed to help women beat chronic bloating, irregular bowels, fatigue, and food sensitivity by restoring gut balance and addressing the root causes of SIBO. The course runs over eight weeks and provides a step-by-step framework for managing symptoms with expert guidance.

The course includes tailored food plans based on your SIBO type, hormone-aware symptom tracking for women, and downloadable tools such as meal plans and symptom trackers. By combining structured education with practical resources, it allows you to follow the Low FODMAP approach in a safe, balanced, and personalised way without the guesswork or risk of unnecessary restriction.

Conclusion

The Low FODMAP diet can be a valuable tool for easing the bloating, gas, and discomfort linked to SIBO, but it’s not a cure on its own. For lasting results, it needs to be combined with accurate SIBO breath testing, tailored dietary support, and strategies that address the underlying causes of bacterial overgrowth.

At IBS Clinics, we provide functional medicine support that goes beyond symptom management. Through services such as hydrogen breath testing and our I Can Beat SIBO course, we help you follow the Low FODMAP approach safely and effectively, while restoring long-term gut balance.

If you’d like to start your journey towards lasting relief, contact us at IBS Clinics today.

References

https://www.monashfodmap.com/about-fodmap-and-ibs/
https://journals.lww.com/ajg/Fulltext/2020/02000/ACG_Clinical_Guideline__Small_Intestinal_Bacterial.9.aspx
https://www.healthline.com/health/sibo-diet#foods-to-avoid

Author – Tracey Randell

At IBS Clinics, Tracey Randell, a renowned Nutritional Therapist and one of the few IFM Certified Practitioners in the UK, extends her specialised knowledge and unique approach to managing and treating IBS and other gut-related conditions effectively.

Tracey’s profound understanding of Functional Medicine allows her to connect the dots for complex health conditions, identifying and addressing the root causes to curate personalised and comprehensive health plans for her patients. Her holistic approach focuses on resolving underlying imbalances and optimising gut health, enabling the body to correct other issues and attain overall well-being.

At IBS Clinics, we are dedicated to being your partner in navigating your gut-related health concerns, offering expert care and individualised treatment plans to alleviate your IBS symptoms and enhance your quality of life.

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