What Should You Not Eat on SIBO?

According to research, up to 78% of people with IBS may also have SIBO, a condition exacerbated by diet. A key step in managing Small Intestinal Bacterial Overgrowth is understanding what should you not eat on SIBO to reduce uncomfortable symptoms like bloating, gas, and abdominal pain.

Quick Summary

A diet for Small Intestinal Bacterial Overgrowth involves temporarily restricting fermentable carbohydrates like high-FODMAP foods, specific fibers, and certain sugars to manage symptoms. It is a temporary strategy used alongside medical treatment to reduce bacterial fuel and alleviate discomfort. This approach requires professional guidance for safe, effective implementation.

Key Points

• Avoid High-FODMAP Foods: Restrict fermentable carbohydrates like those found in garlic, onions, wheat, and certain fruits to reduce bacterial fuel and gas production.

• Limit Processed Sugars and Artificial Sweeteners: Sugary foods, soda, and sugar alcohols like xylitol and sorbitol can exacerbate bacterial overgrowth and worsen symptoms.

• Temporarily Eliminate High-Fiber and Starchy Foods: Cooked-and-cooled potatoes, unripe bananas, and excessive raw fiber can lead to increased fermentation and bloating in some cases.

• Reduce High-Fat Meals and Heavy Foods: Large amounts of fat slow down gut motility, creating a favorable environment for bacterial proliferation.

• Use Diet as a Temporary Tool: A SIBO diet is not a permanent solution and should be followed short-term (e.g., 2-6 weeks) under professional guidance to prevent nutrient deficiencies.

• Consult a Dietitian: Work with a healthcare professional to identify your specific triggers and reintroduce foods safely and systematically.

Understanding SIBO and Its Dietary Triggers

Small Intestinal Bacterial Overgrowth (SIBO) occurs when an excessive number of bacteria populate the small intestine. Normally, the small intestine has a relatively low bacterial count compared to the large intestine. When this delicate balance is disrupted, it leads to the fermentation of food, particularly carbohydrates, which results in uncomfortable and often painful symptoms. The primary goal of a SIBO diet is to starve these overgrown bacteria by limiting their preferred food sources. This typically involves a temporary restriction of high-FODMAP foods, specific types of fiber, and sugars.

High-FODMAP Carbohydrates

FODMAP stands for Fermentable Oligo-, Di-, Mono-saccharides And Polyols. These are short-chain carbohydrates that are poorly absorbed in the small intestine, making them a prime food source for bacteria. Reducing or eliminating high-FODMAP foods is a cornerstone of most SIBO dietary protocols. During the elimination phase, you should avoid:

• Fructans: Found in many vegetables like garlic, onions, asparagus, cauliflower, and broccoli stalks, as well as wheat and rye products.
• Lactose: A natural sugar found in dairy products such as milk, yogurt, and soft cheeses.
• Fructose (in excess): High-fructose fruits like apples, pears, mangoes, and watermelon, along with sweeteners like high-fructose corn syrup and honey, can be problematic.
• Galactans: Found in legumes and beans, including lentils, chickpeas, and soybeans.
• Polyols: Sugar alcohols such as sorbitol, mannitol, and xylitol, commonly found in sugar-free gum, diet foods, and some fruits like apples and apricots.

Other Problematic Foods and Drinks

While FODMAPs are a major focus, other foods can also exacerbate SIBO symptoms by increasing fermentation or slowing digestion. These include:

• Refined sugars and processed foods: Sugary sodas, pastries, candy, and high-fructose corn syrup can feed the overgrowing bacteria, promoting further fermentation and gas production.
• Resistant starches: These starches are not fully broken down in the small intestine and can ferment, especially in methane-dominant SIBO. Examples include cooled leftover rice or potatoes and unripe bananas.
• Certain fibers: While fiber is generally healthy, raw, fibrous vegetables like kale and broccoli stalks can be irritating to an already sensitive gut. High-fiber foods like psyllium, inulin, and fructooligosaccharides (FOS) can worsen symptoms by feeding the bacteria.
• Alcohol and carbonated beverages: Beer, wine, soda, and kombucha can introduce more gas and fermentable ingredients into the digestive system.
• High-fat, heavy meals: Large amounts of fat can slow down gut motility, leading to stalled digestion and further fermentation in the small intestine.

A Comparison of High-FODMAP vs. Low-FODMAP Foods

Category	High-FODMAP (To Avoid)	Low-FODMAP (Generally Tolerated)
Vegetables	Garlic, onions, asparagus, cauliflower, mushrooms, cabbage, broccoli stalks, artichokes	Carrots, zucchini, spinach, bell peppers, cucumbers, green beans, olives, pumpkin
Fruits	Apples, pears, watermelon, cherries, mangoes, dried fruits, peaches, high-fructose fruits	Strawberries, blueberries, grapes, oranges, unripe bananas, lemons, raspberries
Grains	Wheat, rye, barley, high-fructan cereals	Rice, quinoa, oats (gluten-free), cornmeal, gluten-free crackers
Dairy	Cow's milk, ice cream, soft cheeses (cottage cheese, ricotta), yogurt	Lactose-free milk, hard cheeses (cheddar, parmesan), almond milk, lactose-free yogurt
Legumes	Beans, lentils, chickpeas, soybeans	Tofu (firm), tempeh (in moderation)
Sweeteners	Honey, agave, high-fructose corn syrup, sorbitol, xylitol, mannitol	Maple syrup (small amounts), sucrose, glucose, stevia, monk fruit

The Importance of a Structured Approach

Following a restrictive SIBO diet is a temporary measure, not a long-term solution. It's designed to reduce symptoms while addressing the root cause of the bacterial overgrowth with antibiotics or other medical treatments. A low-FODMAP diet is often recommended for 2-6 weeks, after which a reintroduction phase begins. This allows you to identify personal trigger foods and gradually re-expand your diet. Working with a registered dietitian or a healthcare professional is crucial to ensure you don't develop nutritional deficiencies and to safely navigate the reintroduction process. Restrictive diets should not be maintained for long periods without supervision.

Conclusion

Managing SIBO requires a strategic dietary approach centered on removing fermentable carbohydrates that fuel bacterial overgrowth. Avoiding high-FODMAP foods like onions, garlic, wheat, certain fruits, and legumes is a key step in providing symptom relief. Furthermore, limiting processed sugars, alcohol, carbonated drinks, and heavy fats can support improved digestive function. A structured elimination and reintroduction plan, guided by a healthcare professional, offers the best path to identify trigger foods, manage symptoms, and avoid long-term nutritional deficiencies. Diet is a powerful tool for symptom management but should be used in conjunction with a comprehensive treatment plan to address the underlying cause of SIBO.

• Managing Small Intestinal Bacterial Overgrowth (SIBO): What to eat, what to avoid

Frequently Asked Questions

Is a low-FODMAP diet enough to cure SIBO?

No, a diet alone is not a cure for SIBO. While a low-FODMAP diet helps manage symptoms by reducing bacterial fuel, it must be used alongside other medical treatments, such as antibiotics, to eradicate the bacterial overgrowth.

Can I eat all vegetables on a SIBO diet?

No, you should avoid high-FODMAP vegetables like onions, garlic, asparagus, cauliflower, and mushrooms, as these can ferment and worsen symptoms. Instead, focus on low-FODMAP options like carrots, spinach, zucchini, and bell peppers.

What kind of fruits should I avoid with SIBO?

Avoid fruits high in fructose and polyols, including apples, pears, watermelon, and dried fruits. Stick to low-FODMAP fruits like unripe bananas, blueberries, grapes, oranges, and strawberries.

Are grains completely off-limits for SIBO?

Not all grains are off-limits, but you should avoid high-fructan grains like wheat, rye, and barley. Gluten-free grains such as rice, quinoa, and oats are generally better tolerated in moderation.

Why should I avoid alcohol on a SIBO diet?

Alcohol, especially beer and wine, can add more fermentable carbohydrates and gas to your digestive system. Carbonated drinks also add pressure and should be avoided.

Can processed foods make SIBO worse?

Yes, processed foods often contain refined sugars, high-fructose corn syrup, and additives that can fuel bacterial overgrowth and trigger symptoms. It is best to avoid them.

Do I have to give up all dairy for SIBO?

Dairy containing lactose should be avoided, but many people can tolerate lactose-free milk and hard, aged cheeses like cheddar and parmesan. Plant-based milks like almond milk are also good alternatives.