If you're dealing with Small Intestinal Bacterial Overgrowth (SIBO), you know that what you eat can make a huge difference in managing symptoms. Choosing the right foods—and, more importantly, knowing which SIBO foods to avoid—can help calm your gut and keep those pesky symptoms at bay.
In this post, we'll dive into the top SIBO foods to avoid and why they're problematic and provide some easy food swaps to keep your meals both satisfying and SIBO-friendly.
Introduction to SIBO and SIBO diets
If you've been managing chronic bloating, gas, or even fluctuating bouts of diarrhea and constipation, you may have encountered the term SIBO—short for Small Intestinal Bacterial Overgrowth.
SIBO occurs when bacteria start colonizing the small intestine (or maybe the wrong type of bacteria starts causing trouble). Your small intestine isn't meant to house a large number of bacteria—that's more the large intestine's job. Your colon is the place where you can find the gut microbiome (a community of trillions of microorganisms) influencing many organ functions in the body.
The problem starts when these bacteria (that should stay in the large intestine migrate up into the small intestine), causing interference with normal digestion and absorption of food by fermenting carbohydrates and fibers and creating gases (methane, hydrogen, hydrogen sulfide), leading to various uncomfortable symptoms. (1)
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This bacterial shift isn't just inconvenient; it's often the root cause of digestive turmoil, with symptoms that mimic other gut issues but usually respond to antibiotics or unique treatment approaches, particularly dietary adjustments.
The relationship between diet and SIBO is complex. Unlike some conditions where a specific diet might serve as a cure, SIBO diets focus on symptom management rather than an outright solution.
By understanding the impact certain foods have on your digestion, particularly those that ferment quickly and feed bacterial overgrowth, you can make informed choices to alleviate discomfort and potentially reduce SIBO's severity.
If you're looking for a deeper dive into understanding the various SIBO diets, I've already covered the basics in my comprehensive guide to the SIBO Diet — be sure to check it out for more insights on managing symptoms through dietary choices.
The common element in SIBO diets
When managing SIBO, you'll frequently hear about FODMAPs—an acronym that stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are short-chain carbohydrates that ferment quickly in the gut, causing gas and bloating, especially in a sensitive digestive system. (2)
The low-FODMAP diet, which was created by Monash University, has been utilized for IBS (Irritable Bowel Syndrome) symptom management. The diet can help reduce digestive symptoms such as bloating, flatulence, and diarrhea. According to clinical trials, the diet is effective in improving symptoms in up to 70% of IBS patients. (3)(4)
However, the low-FODMAP diet has also gained popularity among SIBO sufferers. How so? Well, there is a connection between IBS and SIBO. Research showed that up to 78% of patients with IBS have SIBO. (5) This explains why the low FODMAP diet is often used for SIBO patients, especially when symptoms are identical to IBS.
So, by focusing on SIBO foods to avoid—namely, those high in fermentable carbohydrates—you'll have a tool to reduce the "fuel" available to bacterial overgrowth.
However, it's essential to remember that while some foods may universally exacerbate SIBO symptoms, every individual's digestive response is unique. Working to identify your specific triggers can make a significant difference in long-term symptom management and relief.
Another important factor to remember is that these FODMAP foods are not the enemy; they might worsen SIBO symptoms, but they are also essential fuel for your gut microbiome for optimal health. So, following any SIBO diet should be a temporary approach - until you work on your gut health - rather than a long-term solution.
Top 5 SIBO foods to avoid
Here's a closer look at the top five foods to avoid if you're managing SIBO symptoms. Each comes with an explanation of why it tends to be problematic, along with a few SIBO-friendly alternatives.
1. Common high-FODMAP vegetables
Garlic and onions, rich in a type of FODMAP called fructans, ferment rapidly in the small intestine. These compounds are notorious for causing gas, bloating, and discomfort, even in those without SIBO. For those with SIBO, these symptoms can be especially pronounced. (6)
Many other vegetables commonly seen as healthy can pose problems for those with SIBO.
Cauliflower, for instance, contains mannitol, a sugar alcohol that can trigger bloating and gas.
Brussels sprouts and apples, too, are high in fermentable carbohydrates that may cause discomfort, particularly because they ferment quickly in the small intestine.
Apples, rich in fructose and polyols, and Brussels sprouts, high in raffinose, can cause significant digestive issues for SIBO sufferers. (7)
Alternatives:
While high-FODMAP vegetables may be problematic, there are plenty of SIBO-friendly (low-FODMAP) swaps.
Garlic substitute: For flavor without the fermentable fiber, consider garlic-infused oils, which capture the aromatic compounds of garlic without including the problematic carbohydrates. This way, you can enjoy your dishes without suffering from the side effects of raw garlic.
Onion substitute: For those missing the flavor of onions, try using the green tops of scallions (also known as green onions and spring onions) or chives, which are lower in FODMAPs and can offer a similar taste. Another option is asafoetida powder (also known as hing -used sparingly – be aware that it may contain gluten!), which can add an onion-like aroma to dishes without triggering symptoms.
Cauliflower substitute: Try using eggplant, zucchini, or broccoli heads in recipes where you'd typically use cauliflower. These alternatives have a similar texture but are lower in fermentable sugars.
Brussels sprouts substitute: Kale, spinach, Bok choy, or Swiss chard can offer a leafy green option without the risk of excess fermentation.
Apple substitute: Jicama (in moderation) can be an excellent alternative due to its crunchy texture, which is similar to apples. But you can also use unripe bananas, blueberries, or strawberries that can provide natural sweetness with a fraction of the fermentable sugars found in apples.
2. Lactose-containing dairy products
Dairy can be challenging for many with SIBO due to lactose, the sugar found in milk. Without enough lactase (the enzyme needed to digest lactose), lactose ferments in the small intestine, leading to bloating and gas. (8)
Besides having lactose intolerance, other components of dairy may also be problematic for certain individuals. Many may also react to casein, the primary protein in dairy (particularly A1 beta-casein found in most dairy cows), which can be inflammatory, hard to digest, and may cause delayed transit time. (9) Interestingly, milk that contains only the A2 type of beta-casein has not been associated with similar inflammatory processes as seen in A1 casein. (10)
Additionally, conventional dairy products may contain added hormones and antibiotics that can disrupt gut balance and aggravate SIBO symptoms. For those with compromised gut health, these factors can worsen inflammation, making dairy a frequent trigger. (11)
Alternatives:
Choose plant-based alternatives like almond or coconut milk, which don't contain lactose or casein – although the ingredient list still needs to be checked as many of these vegan alternatives may contain inflammatory oil, gums, and sweeteners that may also cause digestive upset.
For those who tolerate dairy, organic and grass-fed dairy can be a better option as these products are often free from added hormones and antibiotics; just make sure to opt for lactose-free products.
3. Legumes and beans
Legumes, including beans, chickpeas, and lentils, are high in galacto-oligosaccharides—a type of carbohydrate that's particularly fermentable. They tend to create excess gas and bloating, especially for those with SIBO. This can be particularly frustrating for vegans and vegetarians, as legumes are often a primary protein source in plant-based diets. (12)
Alternatives:
Fortunately, there are ways to enjoy legumes even on a low-FODMAP diet. Tinned legumes, for example, in moderate amounts, often contain lower FODMAP levels, as some of the fermentable sugars leach into the canning liquid, which can be rinsed away before eating. A few examples that may work are cannellini beans, red kidney beans, edamame beans, pinto beans, etc. Check the Monash FODMAP App for the most updated list of legumes.
Additionally, soaking dried legumes overnight, draining and rinsing, and then thoroughly cooking them in fresh water can reduce their fermentability, making them gentler on digestion. You can also add digestion-enhancing herbs like cumin, ginger, and fennel to legume dishes, which may help ease potential discomfort. It's best to test them once the elimination phase is completed.
For other protein alternatives, try tofu or tempeh, which are typically easier to digest for many with SIBO and low in FODMAPs.
4. Sugar alcohols
Sugar alcohols (polyols), often found in "sugar-free" or "diet" products, which are used as sugar substitutes, are notorious for their laxative effects and are poorly absorbed in the small intestine. When they reach the small intestine undigested, they can ferment and exacerbate SIBO symptoms, leading to discomfort and digestive distress like bloating, diarrhea, and nausea. (13)(14)
Here are some of the common sugar alcohols often found in products:
- Sorbitol – Commonly used in sugar-free gums, candies, and some processed foods.
- Mannitol – Found in "sugar-free" chocolates, baked goods and used as a filler in certain medications.
- Xylitol – Frequently used in sugar-free chewing gum, mints, and oral care products like toothpaste.
- Erythritol – Often found in low-calorie or keto-friendly products, including some beverages, protein bars, and baked goods.
- Maltitol – Used in sugar-free chocolates, ice creams, and other sweets. (15)
Alternatives:
There are a few options that may be more suitable for those dealing with SIBO, as these don't ferment in the gut and can satisfy your sweet cravings without the side effects linked to sugar alcohol.
- Stevia: This is a popular choice, as it's low in FODMAPs and doesn't ferment in the gut. Since it's derived from the Stevia plant, it offers sweetness without feeding bacteria in the small intestine. However, because it's very concentrated, it's best used in small amounts to avoid any potential digestive upset. It's also important to find products without added sugar, alcohol, or other problematic ingredients.
- Maple syrup: Pure maple syrup is generally considered low-FODMAP in small servings (up to 1 tablespoon). It's a natural sweetener that's less likely to ferment in the gut compared to honey, making it a SIBO-friendly choice when used moderately.
- Monk fruit (also known as Luo Han Guo): Like Stevia, monk fruit is a natural, low-calorie sweetener that's considered to be low in FODMAPs and typically well-tolerated. It's crucial to choose pure monk fruit extract when possible (so avoid monk fruit blends) and monitor reactions. (It has not been officially tested by Monash University for FODMAP content yet.)
5. Wheat and gluten-containing grains
Wheat and other gluten-containing grains are high in fructans, a type of FODMAP that easily ferments in the small intestine, causing gas and bloating for many with SIBO. (16)
Beyond fructans, gluten itself can be problematic for those with gut sensitivities. Gluten has been associated with "leaky gut" or increased intestinal permeability. This condition occurs when the lining of the small intestine becomes more permeable than it should be, allowing partially digested food particles, toxins, and bacteria to "leak" into the bloodstream. This leakage can trigger immune responses and inflammation, which can worsen digestive symptoms and may contribute to SIBO's persistence. (17)
Additionally, gluten can damage the gut lining, especially in people with existing conditions like celiac disease.
For those with SIBO, consuming gluten-containing grains can add to digestive discomfort and inflammation and exacerbate symptoms like bloating and gas.
Examples of gluten-containing grains:
- Wheat – Found in foods like bread, pasta, cereals, and many baked goods.
- Barley – Often used in soups, beer, and certain cereals.
- Rye – Found in rye bread, crackers, and some alcoholic beverages.
- Triticale – A hybrid of wheat and rye used in certain cereals and breads.
Alternatives:
Quinoa: This is low in FODMAPs in servings of about 1 cup cooked. It's versatile and high in protein, making it a great option for SIBO-friendly meals.
Rice (White Basmati or Jasmine and brown): Both types of rice are low in FODMAPs, with white rice being especially gentle on digestion due to its low fermentation points. Brown rice is also tolerated by most but should be consumed in moderation (about ½ cup cooked) to keep fiber intake manageable.
Millet: Millet is a low-FODMAP grain in servings of about 1 cup cooked. It's easy to digest and works well as a side dish or in salads.
Buckwheat: Buckwheat is generally low-FODMAP and safe in portions of around ⅔ cup cooked. It can be used as a grain alternative or ground into flour for baking.
Sorghum: Sorghum is low-FODMAP in servings of about ½ cup cooked. Its hearty texture makes it a great addition to soups and stews without contributing to fermentation.
Oats (certified gluten-free): Oats are low-FODMAP in servings of about ½ cup rolled oats or ¼ cup steel-cut oats. Look for certified gluten-free oats to avoid any gluten contamination, especially if you're sensitive.
Check the Monash FODMAP App for the most updated list of grains.
Other safe SIBO-friendly alternatives
While navigating dietary restrictions can be daunting, especially at first, numerous SIBO-friendly foods can serve as a foundation for a varied, satisfying diet. The main goal should be to follow a whole-food diet, using fresh ingredients and minimizing processed foods as much as possible.
Here are some options to consider:
- Proteins: eggs, lean meat, poultry, seafood, and lactose-free dairy (if tolerated) provide essential nutrients without feeding bacterial overgrowth.
- Low-FODMAP vegetables: vegetables like spinach, kale, zucchini, tomatoes, carrots, lettuce, and cucumbers are generally lower in fermentable fibers, making them easier on the digestive system.
- Starchy vegetables: potatoes, parsnip, taro root, yams, etc.
- Fruits: blueberries, strawberries, cantaloupe, citrus fruits, etc.
- Gluten-free grains: quinoa, rice, millet, and buckwheat are nutritious, non-fermentable options that won't disrupt your gut health.
- Healthy fats: Olive oil, avocado oil, and coconut oil are excellent sources of healthy fats, supporting your overall health without causing digestive distress.
Experimenting with these alternatives can help you discover a range of SIBO-friendly foods that keep your meals exciting and nutritious while managing symptoms.
Remember that the diet is just one piece of the whole healing process, and most often, it won't solve the underlying reasons for your SIBO. So, if you notice that the low-FODMAP diet is not working for you, then consider another direction. Sometimes, it is better to keep things simple and focus on other areas of your life to manage your gut.
Additional tips for managing SIBO
Managing SIBO effectively often requires a holistic approach that includes not only dietary adjustments but also lifestyle changes and targeted treatments.
Here are some strategies that complement a SIBO-friendly diet:
Meal spacing: In SIBO management, meal timing is just as important as what you eat. Instead of grazing or eating multiple small meals throughout the day, it's often beneficial to space meals about 4–5 hours apart. This approach allows for the migrating motor complex (MMC) to activate—a cleansing wave that helps sweep excess bacteria from the small intestine, reducing the likelihood of bacterial overload. By giving your digestive system this time between meals, you can support natural motility and reduce fermentation. (18)
Addressing underlying causes: SIBO can arise from various causes, including gut motility disorders, insufficient digestive juice production, structural issues in the digestive tract, or even stress/ trauma-related factors. Identifying and addressing these underlying causes can prevent recurrence and promote long-term gut health.
Incorporating probiotics and digestive enzymes: For some, specific probiotics and digestive enzymes can support the gut's natural healing processes, though these should be chosen carefully under the guidance of a healthcare professional.
Stress management: Chronic stress can exacerbate SIBO symptoms by disrupting digestion, gut microbiome balance, and gut motility. (19) Practicing stress-reducing activities like yoga, meditation, or even daily walks can positively impact your digestive health.
SIBO isn't just a condition you can "fix" overnight. It's a complex and sometimes chronic issue that often requires ongoing management.
However, with the right combination of dietary changes and lifestyle adjustments, you can take control of your symptoms and support a healthier, more balanced digestive system.
For a more comprehensive approach to managing SIBO, check out our detailed guide on holistic SIBO recovery. This post covers everything from diet and lifestyle changes to addressing underlying causes for a balanced, whole-body approach to healing.
Conclusion
Living with SIBO means adapting to the challenges of symptom management and dietary restrictions. By focusing on SIBO foods to avoid, such as high-FODMAP vegetables, lactose-containing dairy, legumes, sugar alcohols, and gluten-containing grains, you can make choices that alleviate discomfort and support a healthier gut environment.
Remember, the journey to managing SIBO is highly individual. What works for one person may not work for another, and finding your personal food triggers is crucial. With support and a commitment to both diet and lifestyle modifications, you can forge a path toward lasting relief and a happier, healthier gut.
This post is only for informational purposes and is not meant to diagnose, treat, or cure any disease. I recommend always consulting your healthcare practitioner before trying any treatment or dietary changes.
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Alexandra is a Functional Medicine Certified Health Coach & Holistic Nutritionist specializing in IBS, SIBO, and Gut Health. She helps her clients identify the root causes of their chronic gut issues with functional testing, supporting their bodies holistically and implementing the necessary lifestyle changes long-term to regain control of their bodies and enjoy food freedom. Book your FREE SIBO Assessment call now >>>