Is Tamari Good for IBS? Your Guide to Low FODMAP Condiments

January 3, 2026 •

4 min read

According to extensive testing by Monash University, tamari is generally considered low in FODMAPs, making it a suitable condiment for many people with Irritable Bowel Syndrome. This guide will explore exactly why is tamari good for IBS and how to incorporate it safely into a sensitive diet.

Quick Summary

Many individuals with Irritable Bowel Syndrome can safely enjoy tamari in moderate servings. This article explains how the fermentation process reduces its FODMAP content and highlights why it is often a safer, gluten-free alternative to regular soy sauce.

Key Points

Tamari is generally low FODMAP: Due to the fermentation process, which breaks down the FODMAP carbohydrates in soybeans.
Check for gluten-free: While most tamari is gluten-free, checking the label is essential for those with celiac disease or gluten sensitivity.
Serving size matters: Tamari should be consumed in moderate servings, typically up to 2 tablespoons (42g), to remain within low FODMAP guidelines.
Read labels carefully: Avoid tamari with high-FODMAP additives like garlic or onion powder, which can be found in some seasoned varieties.
Excellent soy sauce alternative: Tamari's robust flavor makes it a suitable substitute for regular soy sauce, especially for sensitive guts.
Longer fermentation reduces FODMAPs: Traditional, slow fermentation methods for tamari result in a lower FODMAP content.

Understanding IBS and the Low FODMAP Diet

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder characterized by symptoms like bloating, abdominal pain, and changes in bowel habits. For many, managing these symptoms involves following a low FODMAP diet, a strategy designed to reduce the intake of specific types of carbohydrates that can trigger digestive distress. FODMAPs, which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, are poorly absorbed by the gut and are fermented by gut bacteria, leading to gas and discomfort.

In their natural state, soybeans contain high levels of the FODMAP known as galacto-oligosaccharides (GOS). However, the processing method of soy is critical in determining its final FODMAP content. Products like tamari, which are created through fermentation and draining, have significantly lower FODMAP levels than other soy products.

The Fermentation Factor: Why Tamari is Different

Tamari's low FODMAP status is a direct result of its production process. Unlike some chemically produced soy sauces, authentic tamari is traditionally made from fermented soybeans, salt, and water. This fermentation process is key to breaking down the problematic FODMAPs. During fermentation, beneficial bacteria and yeast consume the complex carbohydrates and oligosaccharides in the soybeans, rendering the final product much more digestible for individuals with IBS.

This breakdown of carbohydrates results in a complex flavor profile while mitigating the potential for digestive issues. This makes tamari a prime example of a food that starts as potentially high-FODMAP but becomes low-FODMAP through processing.

Benefits of Fermentation for Tamari

Reduction of GOS: The microorganisms involved in fermentation break down the galacto-oligosaccharides, the main FODMAP in soybeans.
Enhanced Flavor: A longer fermentation time, common for tamari, allows for a richer, more umami-forward flavor.
Improved Digestibility: The 'pre-digestion' by microorganisms makes tamari gentler on the gut.

Tamari vs. Soy Sauce: Making the Right Choice for IBS

For those on a low FODMAP diet, the choice between tamari and regular soy sauce is important. While both are fermented soy products, their ingredients differ, and this affects their suitability for managing IBS. Tamari is generally considered the safer option.


Feature	Tamari	Regular Soy Sauce
Key Ingredients	Primarily soybeans, water, salt	Soybeans and wheat are standard
FODMAP Content	Considered low FODMAP (Monash tested)	Also considered low FODMAP due to fermentation, but contains wheat
Gluten-Free	Often gluten-free, but always check labels for certification	Contains wheat and is not suitable for those with celiac disease or gluten sensitivity
Flavor Profile	Richer, darker, and typically less salty	Sharper, saltier flavor due to the wheat content
Serving Size	Low FODMAP portion is typically 2 tbsp (42g)	Low FODMAP portion is typically 2 tbsp (42g)
Ideal For	Anyone on a low FODMAP diet, especially those with gluten concerns	Those on a low FODMAP diet who tolerate wheat well

How to Use Tamari in an IBS-Friendly Kitchen

Tamari is a versatile condiment that can easily replace soy sauce in many recipes. Its rich, savory flavor adds depth to dishes without the risk of high-FODMAP ingredients. Here are some simple ways to incorporate it into your diet:

Marinades: Use tamari as the base for marinades for tofu, chicken, or fish. Combine with low FODMAP ingredients like garlic-infused olive oil, grated ginger, and a splash of maple syrup for a delicious teriyaki sauce.
Stir-fries: Drizzle tamari over low FODMAP vegetables like bell peppers, bok choy, and carrots to bring out their natural flavors.
Dipping Sauce: Mix tamari with a small amount of rice vinegar and a pinch of sesame seeds for a simple, flavorful dipping sauce for sushi or spring rolls.
Soups and Sauces: Add a dash of tamari to broths, sauces, and gravies to create a deeper, more robust flavor.

Remember to check the label for any extra additives that could contain high FODMAPs. Stick to plain, naturally brewed tamari to avoid any hidden triggers like garlic or onion powder.

Authoritative Sources for Further Research

For more information on the low FODMAP diet and tested foods, you can consult authoritative resources like the Monash University website. Their database is considered the gold standard for FODMAP content in foods.

Conclusion: Making Informed Choices for Your Gut

For many individuals with IBS, tamari is a safe and flavorful addition to their diet. Its low FODMAP content, achieved through the fermentation process, makes it an excellent alternative to regular soy sauce, particularly for those with gluten sensitivity. By choosing naturally brewed, certified gluten-free tamari and sticking to moderate serving sizes, you can enjoy rich, umami flavor without triggering digestive upset. As with any new food on a low FODMAP diet, it is wise to test your personal tolerance with a small amount first. With a little care, tamari can help you rediscover the joy of eating without compromise.

Frequently Asked Questions

Yes, authentic tamari sauce is generally considered low FODMAP. The fermentation process used to make it breaks down the galacto-oligosaccharides (GOS) naturally present in soybeans.

Most people on a low FODMAP diet can enjoy tamari in moderate serving sizes. Always check for certified low FODMAP options and look for brands that are naturally brewed and free of high-FODMAP additives like garlic.

Tamari is typically made without wheat, making it a gluten-free and safer alternative for those with celiac disease or gluten sensitivity. While both are fermented, tamari's lack of wheat makes it a more reliable low-FODMAP choice.

According to Monash University, a safe low FODMAP serving size for both tamari and regular soy sauce is approximately 2 Australian tablespoons, or 42 grams.

Yes, some brands like San-J offer certified low FODMAP tamari products. Looking for a certification logo, such as from FODMAP Friendly, can provide extra assurance.

Always check for added ingredients like garlic or onion powder, which are high in FODMAPs. Opt for products with simple, clear ingredient lists: soybeans, water, and salt.

No, tamari is made from soybeans and is not suitable for individuals with a soy allergy. For a soy-free alternative, consider options like coconut aminos.