Is Soy Sauce Low FODMAP? Soy Sauce, Tamari, and Coconut Aminos

Yes, regular soy sauce is low FODMAP at typical serving sizes and is safe for people with IBS. According to Monash University, soy sauce is low FODMAP at 2 tablespoons (42g), which is significantly more than most people use in a single dish. The fermentation process that transforms soybeans and wheat into soy sauce breaks down the FODMAPs (particularly GOS) that are present in whole soybeans, making the final product safe for IBS sufferers.

This is welcome news for anyone who loves Asian-inspired cooking, as soy sauce is a foundational ingredient in countless dishes. Combined with garlic-infused oil and ginger, soy sauce forms the basis of low-FODMAP stir-fries, marinades, dressings, and sauces.

Why Is Soy Sauce Low FODMAP When Soybeans Are Not?

Whole soybeans contain GOS (galacto-oligosaccharides), the same FODMAP found in beans, lentils, and chickpeas. However, soy sauce undergoes an extensive fermentation process that fundamentally transforms its carbohydrate composition:

1. Soybeans and wheat are cooked and mixed with a mold culture (Aspergillus oryzae or Aspergillus sojae)
2. The mold produces enzymes that break down proteins and carbohydrates over days to weeks
3. Salt brine is added, and the mixture ferments for months (traditional brewing) or weeks (chemical hydrolysis)
4. During fermentation, the bacteria and mold consume the GOS and other fermentable carbohydrates as fuel, converting them into simpler compounds

By the time the soy sauce is bottled, the GOS that was present in the original soybeans has been largely broken down. The small amount of remaining carbohydrate is not enough to trigger FODMAP-related symptoms at normal serving sizes.

This is similar to how sourdough bread has reduced fructan content compared to regular bread — in both cases, fermentation does the work of breaking down FODMAPs.

FODMAP Breakdown: Soy Sauce and Related Condiments

Condiment	Serving Size	FODMAP Level	Notes
Regular soy sauce (brewed)	2 tbsp (42g)	Low	Safe for most cooking
Light soy sauce	2 tbsp	Low	Thinner, saltier, commonly used in cooking
Dark soy sauce	2 tbsp	Low	Thicker, sweeter, used for color
Tamari	2 tbsp	Low	Gluten-free option, similar FODMAP profile
Coconut aminos	1–2 tbsp	Low	Soy-free, gluten-free alternative
Teriyaki sauce (commercial)	1 tbsp	Moderate–High	Usually contains garlic, onion, honey
Teriyaki sauce (homemade)	1 tbsp	Low	If made without garlic/onion
Oyster sauce	1 tbsp	Low	Check for garlic in ingredients
Fish sauce	1 tbsp	Low	Fermented, no significant FODMAPs
Hoisin sauce	1 tbsp	Moderate–High	Often contains garlic and onion
Ponzu sauce	1 tbsp	Low	Check for added garlic
Miso paste	Small amount	Low	Fermented soy, low FODMAP at 2 tbsp
Sriracha	1 tsp	Low	Small amounts safe, check for garlic

Tamari vs Soy Sauce: What Is the Difference?

Tamari is a Japanese soy sauce traditionally made with little or no wheat, while standard soy sauce (shoyu) is made with roughly equal parts soybeans and wheat. From a FODMAP perspective, both are equally safe because the fermentation process breaks down the relevant carbohydrates regardless of whether wheat is included.

The important difference is gluten content:

• Regular soy sauce contains wheat and therefore gluten (though the fermentation process breaks down much of the gluten protein)
• Tamari is typically wheat-free and labeled gluten-free (always verify on the label)

If you have celiac disease or non-celiac gluten sensitivity alongside your IBS, choose tamari or a certified gluten-free soy sauce. If gluten is not a concern for you, regular soy sauce is perfectly fine.

Coconut Aminos: A Soy-Free Alternative

Coconut aminos is made from the fermented sap of coconut palm trees combined with salt. It provides a similar umami flavor to soy sauce, though it is milder and slightly sweeter. Coconut aminos is:

• Soy-free: Good for people with soy allergies
• Gluten-free: No wheat involved
• Lower in sodium: About 70 percent less salt than soy sauce
• Low FODMAP: At typical serving sizes of 1 to 2 tablespoons

Coconut aminos works well as a 1:1 substitute for soy sauce in most recipes, though you may need to adjust the salt level since it is less salty. It is an excellent option for people managing multiple food sensitivities.

The Teriyaki Sauce Trap

Teriyaki sauce is one of the most common FODMAP traps in Asian cooking. While the soy sauce base is safe, commercial teriyaki sauces almost always include:

• Garlic: High in fructans
• Onion: High in fructans
• Honey or high-fructose corn syrup: High in excess fructose

This makes bottled teriyaki sauce a risky choice for IBS. Instead, make your own FODMAP-friendly teriyaki sauce:

Low-FODMAP Teriyaki Sauce:

• 3 tablespoons soy sauce or tamari
• 1 tablespoon maple syrup or brown sugar
• 1 teaspoon sesame oil
• 1 teaspoon freshly grated ginger
• 1 tablespoon garlic-infused oil
• 1 teaspoon cornstarch mixed with 1 tablespoon water (for thickening)

Combine in a small saucepan, heat until thickened, and use as a glaze for chicken, salmon, or tofu. This gives you authentic teriyaki flavor without the FODMAP-triggering ingredients.

Using Soy Sauce in Low-FODMAP Cooking

Soy sauce is the backbone of countless low-FODMAP dishes:

Stir-fries: Combine soy sauce with garlic-infused oil, ginger, and sesame oil for a simple sauce. Toss with rice noodles, zucchini, bell peppers, carrots, and your protein of choice.

Marinades: Mix soy sauce with lime juice, ginger, and a touch of brown sugar. Marinate chicken, salmon, or tofu for 30 minutes before grilling or baking.

Fried rice: Season your fried rice with soy sauce, sesame oil, and the green parts of spring onion for a classic low-FODMAP meal.

Dipping sauce: Combine soy sauce with rice wine vinegar, a drop of sesame oil, and thinly sliced chili for sushi and dumplings.

Salad dressing: Whisk soy sauce with rice vinegar, garlic-infused oil, lime juice, and a pinch of sugar for an Asian-style salad dressing over lettuce and vegetables.

Reading Labels on Asian Sauces

When shopping for soy sauce and other Asian condiments, check the ingredients list for these hidden FODMAP sources:

• Garlic or garlic powder: Common in oyster sauce, hoisin, and teriyaki
• Onion or onion powder: Frequently added to prepared sauces
• Honey: Used as a sweetener in teriyaki and some marinades
• High-fructose corn syrup: Added to cheaper teriyaki and stir-fry sauces
• Wheat: Present in regular soy sauce (safe from a FODMAP perspective but relevant for celiac)

When in doubt, use FODMAPSnap to scan the label or ingredient list and quickly check whether a sauce is safe.

Key Takeaways

• Regular soy sauce is low FODMAP at 2 tablespoons — more than enough for any dish
• Tamari is equally safe and is gluten-free (choose this if you have celiac disease)
• Coconut aminos is a soy-free, gluten-free, low-FODMAP alternative
• Commercial teriyaki sauce is usually NOT safe due to garlic, onion, and honey
• Make your own teriyaki with soy sauce, maple syrup, ginger, and garlic-infused oil
• Fish sauce, oyster sauce, and miso are generally low FODMAP in typical amounts
• Check labels on all Asian sauces for hidden garlic, onion, and high-fructose sweeteners
• Fermentation is the reason soy sauce is safe despite soybeans being high FODMAP

Related Reading

• Is Garlic Low FODMAP? — Why garlic-infused oil is safe for Asian cooking
• Is Rice Low FODMAP? — The perfect base for soy sauce-seasoned dishes
• Is Onion Low FODMAP? — The other common hidden FODMAP in sauces
• FODMAP Food Guide: What You Can and Can’t Eat

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This article is for informational purposes only and does not constitute medical advice. The low-FODMAP diet should ideally be undertaken with guidance from a registered dietitian experienced in digestive health. Always consult your healthcare provider before making significant dietary changes.