What Should You Not Eat When You Have SIBO? A Comprehensive Guide

December 15, 2025 •

3 min read

According to the American College of Gastroenterology, most diets proposed for SIBO reduce the intake of foods that are fermented by gut bacteria. For those with small intestinal bacterial overgrowth (SIBO), managing symptoms often means understanding what should you not eat when you have SIBO. The key is to reduce fermentable carbohydrates that feed the excess bacteria in the small intestine, which cause bloating, gas, and pain.

Quick Summary

Managing SIBO symptoms involves avoiding or limiting high-FODMAP foods, certain sugars, lactose-containing dairy, and processed foods that feed harmful gut bacteria and cause discomfort.

Key Points

High-FODMAP Foods: The most important category to limit includes fruits (apples, pears), vegetables (onions, garlic), legumes, and certain grains that are poorly absorbed and ferment in the gut.
Dairy and Lactose: Many people with SIBO struggle to digest lactose, the sugar in dairy products, and should consider temporary avoidance or using lactose-free alternatives.
Refined Sugars and Sweeteners: Sugars, including high-fructose corn syrup, honey, and artificial sugar alcohols (like sorbitol and xylitol), fuel bacterial growth and should be avoided.
Processed Foods: Additives, hidden sugars, and fermentable ingredients in processed foods can worsen symptoms and should be minimized or eliminated.
Individualized Approach: SIBO diets are not one-size-fits-all. A temporary elimination diet followed by a cautious reintroduction phase helps identify specific trigger foods.
Professional Guidance is Recommended: Working with a registered dietitian is crucial for a safe and effective SIBO diet plan that prevents nutritional deficiencies.

Understanding the SIBO Diet

Small Intestinal Bacterial Overgrowth (SIBO) is characterized by an increase in bacteria in the small intestine, leading to fermentation and digestive issues. Dietary modifications are a key strategy for managing symptoms, although they are not a cure. The primary aim is to limit the fermentable carbohydrates that fuel the bacteria. Common SIBO diets, such as the low-FODMAP diet and Specific Carbohydrate Diet (SCD), restrict certain food groups. Since trigger foods vary among individuals, personalized guidance, often from a dietitian, is beneficial.

High-FODMAP Foods: The Primary Culprit

FODMAPs are short-chain carbohydrates that can be poorly absorbed and fermented by gut bacteria, leading to gas and bloating common in SIBO. Avoiding high-FODMAP foods is a common recommendation.

High-FODMAP Fruits to Avoid

Certain fruits high in fructose and polyols can worsen SIBO symptoms. These include apples, pears, cherries, peaches, dried fruit, and watermelon.

High-FODMAP Vegetables to Limit

Vegetables containing fructans and polyols can be problematic. Onions, garlic, cauliflower, mushrooms, artichokes, asparagus, and legumes like beans and lentils are often restricted.

High-FODMAP Grains

Grains containing fructans, such as wheat, rye, and barley, are typically avoided. However, a low-FODMAP diet may allow grains like quinoa, rice, and oats in moderation.

Dairy Products and Lactose

Dairy contains lactose, which can be difficult for individuals with SIBO to digest due to reduced enzyme activity, leading to bacterial fermentation. Milk, soft cheeses, ice cream, and flavored yogurts are high in lactose and often avoided. Lactose-free dairy or non-dairy options like almond or soy milk may be better tolerated.

Sugars and Artificial Sweeteners

Sugars and many sweeteners are easily fermented by bacteria. Refined sugar, high fructose corn syrup, honey, agave nectar, and sugar alcohols like sorbitol and xylitol can exacerbate SIBO symptoms.

Comparison Table: Foods to Avoid vs. Alternatives


Category	High-FODMAP & Trigger Foods (Avoid)	Low-FODMAP & Safer Alternatives	Notes
Vegetables	Onions, garlic, cauliflower, mushrooms, asparagus, artichokes	Carrots, cucumbers, spinach, kale, lettuce, pumpkin, zucchini	Cooked vegetables are often better tolerated than raw.
Fruits	Apples, pears, cherries, peaches, dried fruits	Blueberries, grapes, oranges, strawberries, bananas (firm)	Portion control is important even with low-FODMAP fruits.
Grains	Wheat, rye, barley	Rice (white and brown), quinoa, oats (gluten-free), millet	A low-FODMAP approach is often temporary, with reintroduction later.
Dairy	Milk, soft cheeses, ice cream, flavored yogurt	Lactose-free milk, hard cheeses (in small amounts), almond milk	Individual tolerance to lactose varies, so listen to your body.
Sweeteners	High-fructose corn syrup, honey, agave nectar, sorbitol, xylitol	Maple syrup, sugar (in very small amounts), certain artificial sweeteners	Many artificial sweeteners are also problematic and should be avoided.
Legumes	Beans, lentils, chickpeas	Tofu, tempeh (in moderation), certain canned lentils	Sprouted versions of legumes can be easier to digest.

Processed Foods and Other Triggers

Processed foods often contain hidden high-FODMAPs, additives, and sugars that can worsen SIBO symptoms. Alcohol and carbonated drinks can also be triggers.

The Role of Fiber

Fiber's impact on SIBO is complex. While some high-fiber foods can increase fermentation and symptoms, completely eliminating fiber can negatively affect gut health. A gradual reintroduction of well-tolerated fibers with professional guidance is often recommended.

The Importance of Professional Guidance

Managing a SIBO diet can be challenging. Consulting with a dietitian or gastroenterologist experienced in SIBO is highly recommended to identify personal triggers and create a safe reintroduction plan. Restrictive diets should be supervised to avoid nutritional deficiencies.

Conclusion: Personalization is Key

Dietary management for SIBO is highly individual. While avoiding common fermentable carbohydrates like high-FODMAPs, lactose, and certain sweeteners is a starting point, identifying your specific triggers is crucial. A temporary elimination diet followed by careful reintroduction under professional supervision offers the most effective way to manage SIBO symptoms and improve digestive health.

The Cleveland Clinic provides additional information on SIBO diet guidelines.

Frequently Asked Questions

The low-FODMAP diet is a common approach for SIBO that involves temporarily restricting foods high in fermentable carbohydrates (FODMAPs) to reduce the fuel source for bacteria in the small intestine. It's typically followed by a reintroduction phase.

Yes, white potatoes and sweet potatoes are generally considered low in FODMAPs and may be safe to eat in moderation for most people with SIBO. However, individual tolerance can vary.

Dairy products containing lactose should be avoided, especially in the initial elimination phase. Many people with SIBO find relief by switching to lactose-free or non-dairy alternatives like almond milk.

SIBO, an overgrowth of bacteria, is a common cause of food intolerance symptoms. While food intolerance stems from difficulty digesting specific foods, SIBO can cause these issues through the fermentation of undigested carbohydrates by the overgrown bacteria.

Avoiding all fiber is not necessary or recommended long-term. While some high-fiber foods can worsen symptoms initially, a balanced approach with moderate, well-tolerated fiber sources, often guided by a professional, is best.

A SIBO elimination diet should be temporary and followed under the supervision of a healthcare provider. Long-term restriction is not advised, and a reintroduction phase is necessary to identify your specific triggers.

Most refined sugars, high-fructose corn syrup, honey, and artificial sweeteners containing sugar alcohols (like sorbitol) should be avoided because they feed the bacteria and worsen symptoms.

Eggs are generally considered a safe and nutritious, low-FODMAP protein source that is well-tolerated by most people with SIBO.