What is SIBO blog image

Low FODMAP & SIBO diet: everything you need to know

When it comes to gut issues, it can be difficult to pinpoint your symptoms and grasp what they may be telling you. Irritable Bowel Syndrome (IBS) is one of the most common bowel disorders. But did you know that studies show that ​​60-84% of people with IBS actually have something called SIBO?

What is SIBO?

Small intestinal bacterial overgrowth (SIBO) occurs when the small intestine becomes overrun by bacteria. We are all supposed to have an abundance of certain bacteria in our large intestine, but these bacteria are not supposed to be in abundance in our small intestine. 

If you have SIBO it means that the bacteria have either overgrown from your large intestine into your small intestine or in some cases bacteria can translocate from the oral cavity to the small intestine too. This can cause symptoms such as bloating, burping, wind, nausea, stomach pain, diarrhoea, constipation or loose, pale and foul-smelling stools.

My approach to optimum gut health is to take a full case history and also in some cases to do SIBO testing and/or stool testing to find out what may be causing the digestive issues.  If it is indeed SIBO, I would then suggest a bi-phasic diet plan.  SIBO feeds on fermentable carbohydrates.  These foods are called FODMAPs.  When you eat FODMAPs those pesky bacteria in your small intestine can start to use them as food and cause fermentation, leading to gas, and bloating, By reducing the amount of FODMAPs you consume, you’ll be able to alleviate a lot of the symptoms. 

However, there are nuances, as when digestion is compromised and your gut microbiome is out of wack, you might find you may still be reacting to foods on the diet that may be high in oxalates, salicylates, sulphur or histamine, which an experienced practitioner can help you identify through both symptoms and/or testing.

Low FODMAP / SIBO diet

Diet is a key part of SIBO care and is intended to alleviate symptoms in those who are not feeling well.

The diet I use with my clients was designed by one of the field’s leading experts, Nirala Jacobi, and adapted from Alison Siebecker’s SIBO Specific Diet. It promotes gut health by consuming foods that are less prone to feed the bacteria in the small intestine and cause fermentation, leading to symptoms like pain and bloating.

We start by eliminating FODMAPs, which are a kind of fermentable carbohydrate found in many meals. They provide crucial “food” for our gut flora, but in sensitive individuals, they can cause severe stomach difficulties. High FODMAP foods include many grains, many vegetables, some fruits and some dairy.  

Whilst the thought of restricting your diet might not sound appealing to some, don’t be put off! With a bit of planning and preparation, following a low FODMAP/ SIBO diet doesn’t need to be difficult. You only need to follow the most restrictive form of the diet for a few weeks before you can begin reintroducing foods.

Remember: you should always consult your GP when making significant changes to your diet and by no means should the advice in this blog supersede the advice of your GP.

Foods to avoid with SIBO

While the low FODMAP diet was initially developed to treat IBS, it is now frequently used to treat SIBO as well. The SIBO diet, like the low FODMAP diet, aims to reduce foods that can cause fermentation in your small intestine, which means avoiding foods that normally digest more slowly, such as certain types of fibre and certain sugars like lactose found in dairy.

Phase 1 of the SIBO diet is all about reducing the fermentable carbohydrates to deprive bacteria of their preferred fuel, causing them to die. And, reducing the ongoing inflammation that can damage the intestinal lining to restore healthy digestion.  This phase is stricter and reduces the amount of die-off that can occur when we introduce herbal antimicrobials in phase 2.

Phase 2 allows for more food choices and is usually followed for around 3 months whilst taking herbal supplements.  Once symptoms are 90% resolved we can start to slowly and carefully reintroduce FODMAPs. 

SIBO friendly foods

Foods that quickly break down into simple carbohydrates are beneficial to SIBO because they provide nutrients without nourishing the bacteria in your lower intestines. 

It’s also worth noting – portion size matters. What might start out as a low FODMAP food, can soon become high FODMAP if eaten in large quantities!

Foods that are SIBO-friendly include:

  • Meat, fish, poultry, eggs
  • Quinoa, rice, rice noodles
  • Root vegetables like carrots fruit and vegetables like peppers, tomatoes, cucumber, and squash

Eating out on a SIBO diet

Eating out should be a pleasurable experience. You get to enjoy an evening of wonderful cuisine and pleasant conversation with family or friends, without the chore of cleaning dishes! But, for people on a low FODMAP / SIBO diet, a dinner invitation might be a little more stressful.

Will I be able to eat anything? How will I know what the most appropriate option will be? Maybe I should eat first! It would be easier if I didn’t go! Do these thoughts sound familiar?

While eating out on a low FODMAP diet might be challenging, you shouldn’t have to miss out! Here are a few pointers to help you out:

Phone ahead!

You are not an inconvenience, you are a customer!  When I got SIBO, one restaurant changed their menu to add the amazing meal they did for me to their specials for that night!  

Steak/ Chicken

A classic on most menus. Check that the meat doesn’t have a garlic marinade/sauce, and order plain if necessary. Swap the chips for a side salad or some steamed vegetables (i.e. green beans).


Choose grilled or steamed fish that is not battered. If the marinade isn’t SIBO friendly, ask for the fish plain with some fresh lemon wedges. Other great seafood selections are plain prawns, natural oysters, and grilled scallops.


Whilst most restaurants will have a gluten-free pasta option (check before you go), it’s the sauce that causes the problem. They’re nearly always made with onion, garlic or cream (or all three). If there isn’t a suitable sauce on the menu, ask the chef if they can make one without onion or garlic.

For more tips on enjoying a meal out, check out my blog on 5 Tips for Eating Out on a Low FODMAP Diet.

Final thoughts

Diet is a key component of managing SIBO, but it is not meant as a long-term strategy. In order to have real success, you need to identify the root cause, as opposed to just managing the symptoms with diet.  

It could be mould exposure driving your SIBO, stress (which reduces your digestive secretions), adhesions from surgery, digestive issues or even hypothyroidism.  Strategies I use with my clients include herbal antimicrobials, meal spacing, mindful eating and microbiome restoration.  

If you’ve been considering talking to a nutritionist about your diet or gut health, I offer a FREE 30-minute health and wellbeing review. We’ll chat through your health issues, I’ll give you a couple of simple tips to get started, I’ll explain how I work and the different programme options available to you and if we decide we are a good fit I can help you move forward.  Just, click this link to choose a time that suits you best.

Posted in Blog, Conditions, Diet Types, FODMAP Friendly, Lifestyle, Microbiome.