Can I Eat White Bread If I Have SIBO?

October 19, 2025 •

4 min read

Approximately 15% of Americans are affected by SIBO, or Small Intestinal Bacterial Overgrowth. For those managing this condition, understanding if you can eat white bread if I have SIBO is a common and important dietary question, as refined grains can impact bacterial overgrowth and symptom severity.

Quick Summary

Managing SIBO involves restricting certain fermentable carbohydrates, but white bread may be tolerated in small, controlled portions. The lower fiber content of refined flour makes it potentially less problematic than whole grains, but individual tolerance and proper portion control are crucial. Alternatives like sourdough or certified gluten-free bread are often recommended as safer options.

Key Points

Small Portions Are Key: A single slice of white bread is considered low-FODMAP, but overconsumption can trigger SIBO symptoms.
Sourdough Is Often Better: The fermentation process of sourdough bread reduces fructan content, making it easier to digest for many people with SIBO.
Whole Grains Are Typically Avoided: Unlike refined white bread, high-fiber whole-grain breads are high in fermentable fructans and are generally not recommended during active SIBO management.
Check Your Gluten-Free Bread: While gluten-free can be an alternative, always read labels to avoid other high-FODMAP ingredients used as replacements.
Individual Tolerance is Paramount: Each person with SIBO reacts differently to foods, so careful reintroduction and monitoring of symptoms are necessary.
Seek Professional Guidance: A registered dietitian specializing in SIBO can help create a personalized plan and prevent nutritional deficiencies.

Understanding SIBO and Dietary Triggers

Small Intestinal Bacterial Overgrowth (SIBO) occurs when there is an abnormal increase in bacteria in the small intestine. These excess bacteria ferment carbohydrates from food, a process that produces gases like hydrogen and methane, leading to common SIBO symptoms such as bloating, abdominal pain, diarrhea, and constipation.

Dietary management is a cornerstone of SIBO treatment, focusing on limiting fermentable carbohydrates, collectively known as FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols). High-FODMAP foods can exacerbate symptoms by feeding the excess bacteria.

White Bread: A Refined Carbohydrate for SIBO?

The primary difference between white bread and other breads, especially whole grains, is the refining process. Refined white flour is made from only the endosperm of the wheat kernel, which is lower in fiber and fructans compared to the bran and germ found in whole-grain flour. Fructans are a type of FODMAP that can trigger symptoms in sensitive individuals.

The Low-FODMAP Perspective on White Bread

Because of this lower fructan content, a small, specific portion of standard white wheat bread is often considered low-FODMAP and acceptable during the elimination phase of a SIBO diet. For example, Monash University, a leading authority on the low-FODMAP diet, has tested standard white wheat bread and determined that one slice (35 grams) is a low-FODMAP serving. This is in contrast to whole-grain bread, which is typically high in fermentable fiber and should be avoided.

It is crucial to understand that exceeding this small serving size can push the FODMAP content into a high-risk category and trigger symptoms. This is why moderation is key when considering white bread as part of a SIBO diet.

SIBO-Friendly Bread Alternatives

While white bread might be an option in moderation, several other bread varieties are often better tolerated by SIBO patients due to lower FODMAP content or specific preparation methods.

Sourdough Bread

Sourdough bread is a popular alternative because its long fermentation process involves beneficial bacteria and yeast that break down fructans and gluten. This makes sourdough significantly lower in FODMAPs than conventionally-produced bread, even sourdough made with wheat flour. As a result, Monash University indicates a much larger low-FODMAP serving size for white wheat sourdough bread (two slices or 109 grams).

Gluten-Free Bread

For individuals with celiac disease, non-celiac gluten sensitivity, or those who find they react poorly to gluten, certified gluten-free breads are an option. However, it's vital to check the ingredient list, as some gluten-free products use high-FODMAP starches like chickpea flour or contain added sweeteners like honey or agave. Looking for products that are certified low-FODMAP is the safest approach.

SIBO Bread Comparison Table


Feature	White Wheat Bread	White Sourdough Bread	Whole Grain Bread
FODMAPs	Low in small portion (1 slice)	Low in larger portion (2 slices)	High (due to high fructans)
Fiber Content	Low (refined flour)	Variable, depending on flour	High (bran and germ)
Fermentation	Minimal to none	Long fermentation process reduces FODMAPs	None (most commercial versions)
Gluten	Contains gluten	Contains gluten, but partially broken down	Contains gluten
Recommendation	Safe in measured, limited portions, based on tolerance	Generally better tolerated due to fermentation	Typically avoided during elimination phase

Tips for Incorporating Bread into Your Diet

Start Small and Test: Introduce a single slice of white bread or sourdough and monitor your symptoms. Don't push it. If you have a negative reaction, hold off for a while longer.
Pair Strategically: Combine your bread with healthy proteins and fats, such as a turkey and avocado sandwich on sourdough, to slow digestion and balance your meal.
Check Labels: For gluten-free options, scrutinize ingredients to avoid hidden high-FODMAP additives like inulin, honey, or high-fructose corn syrup.
Maintain Spacing: Some dietary protocols for SIBO, like the Low Fermentation Eating plan, recommend spacing meals 4-5 hours apart to optimize the gut's Migrating Motor Complex (MMC), which cleanses the small intestine.
Prioritize Healing: Remember that diet is part of a larger treatment plan. Work with a healthcare professional to address the root cause of your SIBO for long-term recovery.

The Importance of Personalized Guidance

What works for one individual with SIBO may not work for another. The SIBO diet is not one-size-fits-all, and personalized food tolerance can vary significantly. Consulting with a registered dietitian specializing in SIBO and gut health is highly recommended. They can help you navigate the nuances of your specific condition, understand your triggers, and ensure you maintain a nutritious and balanced diet throughout the healing process.

Conclusion: The Bottom Line on White Bread and SIBO

In summary, the answer to "can I eat white bread if I have SIBO?" is cautiously yes, for some individuals, and in specific, limited portions. Because it's a refined grain, a small slice is often low enough in fermentable fructans to be tolerated. However, alternatives like traditional sourdough, with its naturally reduced FODMAP content, are often a safer and more gut-friendly choice. Ultimately, paying close attention to your body's individual response, adhering to proper portion sizes, and working with a healthcare provider are the most effective strategies for managing SIBO and integrating bread back into your diet successfully. A personalized, mindful approach is always best for your unique digestive health journey. For more information on the low-FODMAP diet, you can refer to the definitive guide developed by Monash University(https://www.monashfodmap.com/).

Frequently Asked Questions

White bread is made from refined flour, which is primarily the low-fiber endosperm of the wheat kernel. This process removes most of the high-fructan components found in whole-grain flours. As a result, small servings of white bread contain fewer fermentable carbohydrates that feed SIBO bacteria, whereas whole wheat bread is high in these carbohydrates and is typically avoided.

According to low-FODMAP guidelines from Monash University, a single slice (35 grams) of standard white wheat bread is considered a safe, low-FODMAP serving. Consuming more than this amount in one sitting can increase the FODMAP load and potentially trigger symptoms.

Sourdough bread is generally better tolerated because its fermentation process reduces fructan levels. However, not all sourdough is created equal. Traditional, long-fermented white wheat sourdough is the best option. Always consider your personal tolerance and source your sourdough from a reputable bakery.

A gluten-free diet is only necessary for SIBO if you also have celiac disease or a non-celiac gluten sensitivity. For others, gluten itself isn't the primary issue, but rather the high FODMAP content of many gluten-containing grains. Be cautious when switching to gluten-free foods, as some replacements can also be high in FODMAPs.

For SIBO breath test preparation, a very strict "prep diet" is required for 1-2 days beforehand. Plain white bread is often explicitly allowed during this phase, as it is a low-residue, low-fiber carbohydrate source that is easily digested and won't interfere with test results.

Good low-FODMAP toppings include a thin spread of butter or margarine, peanut butter, lactose-free cream cheese, or simply salt and herbs. Be sure to avoid high-FODMAP spreads like honey or certain jams.

The best way to determine if white bread is a trigger is to follow a guided SIBO diet and then reintroduce it in a small, controlled portion while tracking your symptoms. If you experience bloating, gas, or other discomfort after consumption, it may indicate a personal intolerance.