How much gluten is low in fodmap? A comprehensive guide

December 21, 2025 •

4 min read

While many assume a low FODMAP diet is automatically gluten-free, this is a common misconception; in fact, gluten is a protein, whereas FODMAPs are fermentable carbohydrates, a key difference that impacts how much gluten is low in fodmap. The confusion arises because many gluten-containing grains, like wheat, are also high in FODMAPs, but not all of them. Understanding this distinction is vital for those managing conditions like IBS.

Quick Summary

The low FODMAP diet is not inherently gluten-free, but it does significantly restrict high-FODMAP grains like wheat, barley, and rye. Some gluten-containing foods are acceptable in low FODMAP amounts, while many gluten-free products can still be high in other FODMAPs. The key is to distinguish between gluten sensitivity and fructan intolerance, as the low FODMAP approach focuses on reducing fermentable carbohydrates rather than eliminating protein entirely.

Key Points

Gluten is a protein, not a FODMAP: The core confusion stems from the fact that many gluten-containing grains, like wheat, are also high in the FODMAP fructans.
Low FODMAP diet is not strictly gluten-free: For managing IBS, some gluten-containing foods like certain sourdoughs or small servings of wheat bread are permitted because their fructan content is low enough.
Gluten-free does not guarantee low FODMAP: Many processed gluten-free products can be high in other FODMAPs like honey, inulin, or chickpea flour, which are often added to improve texture.
Dosage is key on a low FODMAP diet: Unlike celiac disease, which requires a zero-gluten diet, the low FODMAP approach allows for small, tolerable amounts of certain high-FODMAP foods.
Fermentation can reduce FODMAPs: Traditional sourdough fermentation processes reduce the fructan content in wheat bread, making it more tolerable for those with IBS.
Celiac disease requires a strict gluten-free diet: The low FODMAP strategy only applies to individuals with IBS. Those with celiac disease must avoid all gluten regardless of the FODMAP content.

Understanding the Core Difference: Gluten vs. FODMAPs

To understand how much gluten is low in FODMAP, you must first grasp the fundamental difference between the two. Gluten is a protein found in wheat, barley, and rye. It provides structure and elasticity to baked goods. Conversely, FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) are a group of short-chain carbohydrates that are poorly absorbed by the small intestine in some people. These carbohydrates travel to the large intestine, where bacteria ferment them, causing gas, bloating, and pain in individuals with Irritable Bowel Syndrome (IBS).

Many foods that are high in gluten, such as traditional wheat bread and pasta, are also high in FODMAPs, specifically fructans, which are a type of oligosaccharide. This overlap is the primary reason for the widespread confusion. However, the low FODMAP diet's primary goal is to reduce the intake of fermentable carbs, not to eliminate gluten protein itself. For individuals with celiac disease, a strict, lifelong gluten-free diet is medically necessary, and any gluten intake is unsafe. For those with IBS but no celiac disease, some gluten-containing foods may be tolerated in specific, low-FODMAP serving sizes.

Low FODMAP, Not No-Gluten: Key Examples

Contrary to popular belief, a low FODMAP diet doesn't require you to eliminate all gluten-containing products. Monash University's research has shown that certain processing methods, like fermentation, can significantly reduce the fructan content in grains, making them low FODMAP. It is the fructan content, not the gluten, that is the concern for IBS management. For instance, authentic, long-fermented wheat or spelt sourdough bread often has a low enough fructan level to be considered low FODMAP in specific serving sizes, even though it still contains gluten. Other examples of gluten-containing foods that are low FODMAP in limited quantities include:

One slice (35g) of plain white (wheat) bread in the USA.
Two tablespoons of soy sauce (which contains wheat).
Small serves of wheat-based pasta, typically around ½ cup cooked.
Two plain wheat cookies or crackers.
A ¼ cup serving of rolled oats (in the US; check for certified gluten-free if necessary).

It's important to use the Monash University FODMAP app to check serving sizes and updates, as levels can vary by region and processing.

Navigating the Gluten-Free Aisle: Hidden FODMAPs

A common mistake for individuals new to the low FODMAP diet is assuming that all gluten-free products are automatically safe. Unfortunately, this is not the case. Many manufacturers add high FODMAP ingredients to gluten-free foods to improve texture and flavor, which can trigger symptoms. Common culprits include:

High FODMAP Flours: Gluten-free products might use flours like chickpea, lentil, coconut, or almond flour (in larger amounts).
Sweeteners: High FODMAP sweeteners such as honey, agave syrup, and high-fructose corn syrup are often used.
Fibers and Inulin: Ingredients like inulin or chicory root fiber are frequently added to increase a product's fiber content, but these are high FODMAP.

Checking the ingredient list is crucial, even on products labeled as gluten-free. Just because the gluten protein is removed does not guarantee the product is free of fermentable carbohydrates. This is why a certified low FODMAP product is a safer bet, as it has been tested and verified to be low in all FODMAP categories at the specified serving size.

Low FODMAP vs. Gluten-Free Diet: A Comparison

The table below outlines the key differences between a low FODMAP diet and a gluten-free diet for managing digestive symptoms.


Feature	Low FODMAP Diet	Gluten-Free Diet
Primary Target	Fermentable Carbohydrates (FODMAPs)	Gluten Protein
Intended Population	Individuals with IBS symptoms	Individuals with Celiac Disease or NCGS
Strictness	Designed in three phases (elimination, reintroduction, personalization); small amounts of some trigger foods may be tolerated after reintroduction.	Must be strictly adhered to for life; even trace amounts of gluten are harmful to those with celiac disease.
Wheat Products	Avoids most wheat products due to high fructan content, but certain preparations (e.g., sourdough) and small servings may be low FODMAP.	Avoids all wheat, barley, and rye, regardless of preparation.
Oats	Low FODMAP in specific servings; certified gluten-free is recommended if potential cross-contamination is a concern for those with celiac disease.	Must be certified gluten-free to avoid cross-contamination with wheat during processing.
Cross-Contamination	Generally not a major concern, as the goal is to manage symptoms, not prevent autoimmune damage.	Critical concern; even trace amounts of gluten must be avoided.

Conclusion: Navigating the Intersection of Gluten and FODMAPs

For those seeking to manage digestive discomfort, understanding how much gluten is low in fodmap is about distinguishing protein from carbohydrates. The low FODMAP diet is not inherently a gluten-free diet, but it does significantly reduce the intake of grains that are high in both gluten and fructans. Crucially, some gluten-containing foods are low FODMAP in moderate servings, while many gluten-free products can contain hidden high FODMAP ingredients. By focusing on the fructan content rather than the gluten and following a structured elimination and reintroduction process, individuals can effectively manage IBS symptoms without unnecessary dietary restrictions. If you have celiac disease, a strict gluten-free diet is required, but if you have IBS, the focus should remain on FODMAPs to pinpoint your specific triggers.

Authoritative Resource for Further Reading:

Monash University Low FODMAP Diet Guide: The creators of the low FODMAP diet offer the most reliable and up-to-date information on FODMAP content in foods. [https://www.monashfodmap.com/ibs-central/i-have-ibs/get-the-app/] (Note: this is not a markdown link as it points to an app, but the URL is provided for reference per the prompt rules for citations)

Frequently Asked Questions

No, a low FODMAP diet is not the same as a gluten-free diet. A low FODMAP diet limits fermentable carbohydrates, while a gluten-free diet eliminates the gluten protein. The two diets overlap because wheat, rye, and barley contain both gluten and high levels of fructans (a FODMAP).

The type and serving size of wheat are key. Some wheat-based foods, like traditionally made sourdough bread, have lower fructan content due to the fermentation process. For IBS management, small, controlled portions of these specific items can be low FODMAP, as verified by Monash University.

For most people following a low FODMAP diet for IBS, cross-contamination is not a concern because they are managing carbohydrate intake, not an autoimmune disease. However, those with a celiac disease diagnosis must avoid cross-contamination entirely.

No, many gluten-free products contain other high FODMAP ingredients, such as chickpea flour, high-fructose corn syrup, honey, or inulin. Always check the ingredient list for hidden FODMAPs or look for products with a certified low FODMAP logo.

The key is to distinguish between the two. Gluten is a protein relevant to celiac disease, whereas FODMAPs are carbohydrates relevant to IBS. Focusing on the specific FODMAP content of foods, rather than just the presence of gluten, is the most effective strategy for managing IBS symptoms.

Oats are naturally gluten-free but can be cross-contaminated with wheat during processing. A specific serving size of regular oats is low FODMAP, but those managing celiac disease need to ensure they purchase certified gluten-free oats.

Many people with IBS who feel better on a gluten-free diet are actually reacting to the high fructan content of wheat, barley, and rye, rather than the gluten protein itself. The 'gluten-free' change unintentionally removes a major source of FODMAPs.