👆 The essentials at a glance
- SIBO (Small intestinal bacterial overgrowth) describes an increased colonization of bacteria in the normally sparsely populated small intestine. This leads to symptoms such as bloating, abdominal distention, diarrhea, and constipation.
- The mislocated bacteria utilize specific substances from the diet and metabolize them. This can aggravate symptoms.
- For symptom control, a diet that temporarily avoids this specific form of carbohydrates can be helpful. Which foods these include is discussed below.
SIBO and Sensitive Digestion: Your Food Compass
Contents
1. What is SIBO (small intestinal bacterial overgrowth)?
2. How do symptoms develop in SIBO?
3. Which diet is suitable for SIBO?
4. Popular foods under the microscope
4.1 Nuts
4.2 Jam and spreads
4.3 Sweeteners and sweets
4.4 Snacks, finger food, and chips
4.5 Bread, pastries, and rice
4.5.1 Bread
4.5.2 Pastries
4.5.3 Rice
4.6 Fruit
4.7 Cucumber, carrot, onion, garlic, and other vegetables
4.7 Eggs, fish, and meat
4.8 Psyllium husk and other fibers
5. Summary
6. FAQs
1. What is SIBO (small intestinal bacterial overgrowth)?
SIBO (Small Intestinal Bacterial Overgrowth) refers to an excessive proliferation of bacteria in the small intestine that causes IBS-like symptoms. The bacteria that are mislocated there ferment certain carbohydrates from food and thus form gases. Diagnosis is made using a breath test 
with glucose or lactulose (increase in H₂ ≥ 20 ppm within ≤ 90 min). In methane producers, the more precise term is IMO (Intestinal Methanogen Overgrowth).
2. How do symptoms develop in SIBO?
The symptoms of small-intestinal bacterial overgrowth (SIBO) arise from fermentation and gases: the overgrowing microbes ferment carbohydrates, producing gases and certain metabolites. These cause symptoms such as bloating and abdominal pain . In addition, the intestinal barrier, its permeability (keyword “leaky gut “), and the immune response can be altered. In severe cases, there is reduced absorption of nutrients and deficiencies (e.g., vitamin B12, vitamin D, iron) (1). Further symptoms can include either diarrhea or constipation (predominantly in IMO ), as well as brain fog and difficulties concentrating.
3. Which diet is suitable for SIBO?
In principle, the diet for SIBO is designed so that so-called FODMAPs are reduced in the diet for a limited time. FODMAPs are an abbreviation for fermentable oligo-, di-, monosaccharides and polyols. These are found, for example, in:
- Oligosaccharides: Fructans (e.g., wheat, rye, onion) & GOS/galactans (legumes).
- Disaccharides: Lactose (milk, soft fresh cheeses, milk drinks).
- Monosaccharides: e.g., fructose (e.g., apple, pear, mango, honey).
- Polyols: sugar alcohols such as sorbitol, mannitol, xylitol, maltitol (erythritol is usually better tolerated; needs to be tested individually).
SIBO symptoms arise through bacterial fermentation of FODMAPs from the diet. This then leads to the symptoms mentioned above, such as gas formation, abdominal distention, bloating, and abdominal pain. The low-FODMAP diet is normally used in IBS and is primarily for symptom control in SIBO. The portion sizes of the foods consumed from the respective groups are crucial. This can also vary greatly from person to person.
4. Popular foods under the microscope
Below we take a closer look at individual food groups and their tolerability in small-intestinal bacterial overgrowth.
4.1 Nuts
Common “no-gos” in larger amounts include cashews and pistachios (GOS/fructans). Better tolerated (in moderate portions) are: macadamias, peanuts, pecans and walnuts. Please consume hazelnuts only in small amounts (e.g., approx. 15 g).
4.2 Jam and spreads
Use caution with sweet spreads and jams. It’s easy to consume too much fructose, especially if a jam contains a lot of apples or pears. When possible, choose a berry jam (e.g., strawberry) made with just fruit and sugar. Berries are often better tolerated than other fruits in SIBO. Also watch for polyols (sugar alcohols such as sorbitol and xylitol), which are commonly added to reduced-sugar or sugar-free jams as sweeteners. If you have SIBO, a jam sweetened with regular sugar is usually the safer choice.
With chocolate-hazelnut spreads, it depends on the ingredients used and the amount of nuts. Again, it’s best to try only small portions.
For savory spreads it likewise depends on the exact ingredients. For
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Nut butters follow the nut rules above in chapter 4.1. Choose macadamia butter rather than hazelnut butter.
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e.g., hummus often has an unfavorable combination of garlic and chickpeas, both of which are very high in FODMAPs. Low-FODMAP versions can be made with rinsed canned chickpeas and garlic-infused oil, in small portions.
4.3 Sweeteners and sweets
Sweeteners and sweets are often poorly tolerated in SIBO. Looking at the different sweeteners, the following stands out:
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Sugar alcohols such as sorbitol, mannitol, xylitol, and maltitol belong to the polyols and are classic triggers for bloating/diarrhea; therefore caution is advised with “sugar-free” candies, bars, spreads, jams, and other packaged sweets.
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Erythritol is a special case: it is largely absorbed in the small intestine and excreted unchanged, making it usually less fermentable and better tolerated. Nevertheless, individual tolerance must be considered.
- Fructose: Fructose is especially problematic when the fructose content of a food is higher than its glucose content. This is the case, for example, with honey, which is considered poorly tolerated.
- Table sugar (sucrose): is generally relatively unproblematic and can be eaten in small amounts. Rice syrup and maple syrup are also considered well tolerated alternatives.
4.4 Snacks, finger food, and chips
On the whole, convenience foods are difficult to tolerate due to their typically long ingredient lists and the frequency of problematic ingredients. It is therefore important to pay close attention to the ingredients and opt for short lists. In the case of chips, try options that contain only potatoes, oil, and salt—without onion and garlic powder, without inulin and chicory fiber, and without sweeteners.
4.5 Bread, pastries, and rice
4.5.1 Bread
What matters here is which ingredients are in the bread and how it was prepared. Wheat and rye, for example, contain fructans, which are often poorly tolerated. Traditionally fermented sourdough bread (e.g., spelt sourdough) has reduced FODMAP contents due to fermentation and is better tolerated by many (brand/recipe & portion are decisive). In addition, check whether other ingredients (besides water and grain) are included, such as certain sugars, nuts, seeds, etc., which can also trigger symptoms.
4.5.2 Pastries
It is similar with pastries: wheat, honey, dried fruits, and sorbitol often make pastries high in FODMAPs. Smaller portions and alternatives (e.g., sourdough-based, without polyols) can be tested individually.
4.5.3 Rice
White rice is generally considered well tolerated in SIBO because it is low in FODMAPs. However, there are differences between rice varieties, and individual tolerances should also be considered. White rice and glutinous rice are often better tolerated because they provide quickly digestible carbohydrates that are rapidly absorbed by the small intestine and therefore provide less substrate for bacteria. Parboiled rice and brown rice are more often described as less well tolerated because they contain more fiber and slowly digestible carbohydrates that remain in the gut longer and can be fermented by bacteria. It is important to use only freshly cooked rice. When rice cools after cooking, resistant starch forms. This, in turn, is used by gut bacteria for fermentation, which can cause problems.
4.6 Fruit
Fruit often causes problems for people with SIBO due to high amounts of fructose and sorbitol. Apples, pears, mango, and dried fruits, as well as stone fruits, are particularly affected. More on this in the article on fruit for SIBO.
4.7 Cucumber, carrot, onion, garlic, and other vegetables
Cucumber and carrot are generally well tolerated by many people with SIBO. Carrots are better tolerated when steamed than raw. Onion and garlic, on the other hand, are high in FODMAPs (especially fructans) and frequently cause symptoms. In this case, it is smarter to use onion/garlic-infused oil. You can download a recipe below:
Other well-tolerated vegetables include zucchini, fennel, pak choi, and spinach.
4.8 Eggs, fish, and meat
Eggs, meat, and fish belong to the foods that—provided there is no individual intolerance/allergy—can generally be eaten without issue. What’s important with meat is the difference between sausage/cold cuts and minimally processed meat. Sausages/cold cuts or further processed (e.g., marinated) meats often contain many additives and seasonings such as onion and/or garlic powder. These can be problematic. It therefore makes sense to choose, for example, unprocessed beef steak, chicken, sea fish, etc.
4.9 Psyllium husk and other fibers
For symptom control in IBS, guidelines recommend soluble fibers, especially psyllium; not, for example, wheat bran (which is insoluble). It is important to increase slowly. In SIBO, psyllium (as a minimally fermentable, gel-forming fiber) can also be helpful. This must be tested individually. Partially hydrolyzed guar gum (PHGG) and pectin are also often well tolerated. In contrast, inulin and chicory root fiber are problematic.
5. Summary
Diet plays a major role in symptom control in SIBO. It may be sensible to avoid very high-FODMAP foods for a period of time to reduce symptoms. However, this should not be done over a long period, otherwise the diversity of the gut microbiome—that is, the variety of microbes in the intestine—will suffer.
6. FAQs
Which foods are suitable for SIBO?
The best tolerated foods are those with a low FODMAP content. These include, for example, eggs, soluble fibers such as psyllium, certain nuts, and selected fruits and vegetables. It is important not only to pay attention to the food group but also to the portion size.
Which foods are often difficult to tolerate with SIBO?
These include convenience foods, sugar alcohols and certain sweeteners, many types of fruit, bread and pastries not made with sourdough, as well as some fibers and types of nuts.
Sources
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- Pimentel, M., Saad, R.J., Long, M. D. & Rao, S. S. C. (2020). ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth; Am J Gastroenterol; 115:165–178. https://doi.org/10.14309/ajg.0000000000000501; published online January 8, 2020; Darmzentrum Bern
- Quigley, E. M. M., Murray, J. A. & Pimentel, M. (2020). AGA Clinical Practice Update on Small Intestinal Bacterial
Overgrowth: Expert Review; Gastroenterology 2020;159:1526–1532. giboardreview.com - NICE Guideline IBS (CG61, last reviewed 30.04.2025).
- Chey, W.D., Hashash, J.G., Manning, L. & Chang, L. (2022). AGA Clinical Practice Update on the Role of Diet in Irritable Bowel Syndrome: Expert Review; Gastroenterology 2022; 162 (6): 1737–1745. AGA
- Sharabi, E. & Rezai, A. (2024); Small Intestinal Bacterial Overgrowth. Current Infectious Disease Reports (2024) 26:227–233; https://doi.org/10.1007/s11908-024-00847-7. Link
- Mares, C. R., Sasaran, M. O. & Marginean, C. O. (2024). The relationship between small intestinal bacterial overgrowth and constipation in children — a comprehensive review. Frontiers (2024). 14; https://doi.org/10.3389/fcimb.2024.1431660
- Monash University
- Lucas Zapata P. et al. (2024) in “An Pediatr (Engl Ed)” with DOI: 10.1016/j.anpede.2024.06.005
