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10 foods to avoid when you have SIBO





One of the biggest challenges of having SIBO (small intestinal bacterial overgrowth) is deciphering which foods trigger your symptoms and which are 'safe'. Meals become a minefield and knowing what to avoid is very confusing.


The bacteria that have taken hold in your small intestine ferment certain foods and it's this fermentation that creates classic SIBO symptoms of gas, bloating, and gut pain. Doing your best to avoid the common offenders will not only reduce discomfort but will also help to starve the unwanted bacteria.


The following is a general guide to some of the main foods to avoid, or, at the very least, minimise. Keep in mind that, while your SIBO will improve by eliminating these, you will still need to combine diet with the right supplements to achieve a full recovery. We have specially selected supplements in our online store that I have found to be very effective in my clinical practice.


It is best to cut out these triggering foods for around the first 4 weeks of treatment. After that time, providing you have used antimicrobial supplements to address the SIBO, you should be able to start reintroducing foods very gradually, testing small amounts systematically.


If you are having a hard time working out what to eat, download our free 7-day meal plan.


If you would like guidance, please contact us or book a free 15 minute phone consultation. Full consultations that include specific diet and supplement advice tailored to your needs are also available.






1. Garlic




This is usually the biggest trigger of symptoms and one of the last foods to reintroduce once you have had treatment. On the plus side, most (but not all) SIBO sufferers can tolerate garlic-infused olive oil.


2. Onions




Like garlic, onions are one of the last foods to reintroduce, and usually very triggering for almost everyone. Watch out for onion powders hidden in items such as stock powder or liquid.


3. Grains




Except for jasmine or basmati rice. Avoid brown rice, wheat (pasta, bread etc), oats, millet etc. Quinoa (not strictly a grain) is sometimes tolerated by SIBO sufferers, so worth testing a little (start with 1/4 cup cooked).


Watch out for flours added to cheap herb spice mixes.


4. Fruit




Lemons and limes are the exceptions, and these can be freely consumed. Having said that, many people can tolerate a little avocado (around 1/4 of an avocado), and banana (1/2 to a 1/4 of a small banana), and you can also test a few berries (1 tbsp max).


5. Thickeners




These include carrageenan, all the gums (guar, xanthan, gellan, locust bean), pectin, and starches, such as corn starch, arrowroot, and tapioca flour. These are often found in non-dairy milks.


Non-dairy milks that only use brown rice as the thickeners tend to be fairly well tolerated. To avoid thickeners completely, you may find it easier to make your own almond milk.


6. Fermented foods




In the normal way, I would be recommending fermented foods for gut health, but in SIBO they are a no-no as they tend to activate the bacteria in the small intestine. Fermented foods include sauerkraut, kimchi, kefir, yoghurt, miso, kombucha. You may be able to tolerate a little soy sauce but you would need to test this.


Vinegar is well tolerated, except for balsamic.


Alcohol is also a fermented food but, at a push, most people are ok with clear spirits, such as gin.


7. Legumes




The fermentable carbohydrates in legumes are very likely to activate bacteria residing in the small intestine. However, tofu and tempeh are OK to consume, and sprouted legumes are also well tolerated. See my earlier blog that shows you how to sprout lentils.


When you start to reintroduce legumes, start with small amounts of brown lentils and move on from there.


8. Mushrooms




Mushrooms contain polysaccharides and polyols (see below), both problematic in SIBO. Constituents vary, depending on the type of mushroom but it is generally best to steer clear at least in the first few weeks of treatment.


Medicinal mushroom supplements tend to be OK as you are only consuming small quantities.


9. Sugar alcohols




Sugar alcohols are found in various plant foods (e.g mushrooms) and are also used as natural sweeteners, e.g xylitol, sorbitol, and generally anything with 'ol' on the end. If you need to sweeten something, pure stevia is best. Some people can tolerate a litttle honey or refined sugar, but you would need to test this.


10. Potatoes




Sadly, these have to go off the menu, at least in the short-term, because of the starches they contain. Sweet potato should also be avoided for the first 4 weeks of treatment.






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