Soy Sauce
Tested serving
- About 2 tablespoons (40mL)
Soy sauce is Low FODMAP at about 2 tablespoons (40mL), a fermented seasoning used in small splashes.
- At about 2 tablespoons (40mL) soy sauce is low, as fermentation breaks down the fermentable carbs in the soy and wheat and no FODMAP group reaches a meaningful level.
A drizzle to finish a dish adds deep savory flavor, and a certified gluten-free tamari works the same way if you avoid wheat.
Why soy sauce is rated low
Soy sauce is low at about 2 tablespoons (40mL), which is the answer most people are looking for before a stir fry. No single FODMAP group stands out for it, so what builds as you pour more is the overall FODMAP load. Low is not the same as unlimited, though, and 2 tablespoons is already a generous seasoning for one plate. The bigger risk for most people is not the soy sauce itself but the bottled sauce it arrives inside.
What changes your risk
- Serving size about 2 tablespoons (40mL) is low. Treating soy sauce as a seasoning rather than a pouring sauce keeps it within that amount.
- What else is in the bottle Teriyaki, hoisin, oyster sauce, black bean sauce and most jarred stir fry and marinade sauces are built on soy sauce and then list onion or garlic in the same ingredient line. Those bring FODMAPs that plain soy sauce does not, and they are usually what turns a meal rather than the soy sauce.
- Dipping versus cooking Poured into a dipping dish, soy sauce is used generously and is hard to keep track of. Stirred through a dish that serves several people, the same bottle is divided across the plates, so the amount landing on any one plate is much easier to keep within the low serve.
- The rest of the meal Because no single group stands out here, stacking with soy sauce is about the whole meal's FODMAP load. Soy sauce sitting low does nothing to offset noodles, a sauce base or a side that is carrying a load of its own.
What else works
For a low food the useful list is the lookalikes rather than the replacements, and the lookalikes here are the thicker bottles on the same shelf. Teriyaki, hoisin, oyster sauce, black bean sauce and jarred stir fry sauces are not soy sauce with extras, they are usually onion and garlic sauces with soy sauce in them, and they need the label read. Tamari is worth knowing about: it is generally made without wheat, which matters if gluten is also being avoided, but it has its own serve and is not a licence to pour more. For building the same savoury depth without leaning harder on the bottle, garlic infused oil, toasted sesame oil, ginger, chives, the green tops of spring onions and a pinch of asafoetida all pull their weight.
How to keep it low
Buy plain soy sauce or tamari and build sauces yourself rather than starting from a jar, since that is where onion and garlic get in. At the table, pour into a dipping dish rather than over the plate, because the amount stays visible that way and about 2 tablespoons (40mL) is much easier to hold to. When a recipe calls for a marinade, measure the soy sauce into the marinade and spread it across the whole dish rather than finishing each plate with more. Eating out, ask for sauce on the side so the kitchen's pour is not the one that decides, and be aware that house stir fry sauces and dumpling dips are usually garlic based even when soy sauce is the first thing you taste.
Common questions
is soy sauce low fodmap
Yes, at about 2 tablespoons (40mL), which is low.
how much soy sauce can i have on a low fodmap diet
About 2 tablespoons (40mL) is low. That is a generous seasoning for one plate, so measuring it once is more useful than pouring by eye.
is tamari better than soy sauce for fodmaps
Tamari is usually made without wheat, which matters for gluten, but it has its own serve rather than a free pass. Measure it the same way rather than pouring more.
can i use soy sauce on the elimination phase
Yes, at about 2 tablespoons (40mL). The thing to watch during elimination is not the soy sauce but the teriyaki, hoisin, oyster and stir fry sauces it gets blended into, which commonly list onion and garlic.
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Where this rating comes from
Soy Sauce is rated from published lab measurements of its FODMAP content, using the low, moderate and high cutoffs of Varney et al. (2017).
Feedback sent through the FODMAP Foods app has led to changes in this list.
Sources
- Fructan and free fructose content of common Australian vegetables and fruit. Muir et al. (2007), J. Agricultural and Food Chemistry 55(16):6619-6627.
- Measurement of short-chain carbohydrates in common Australian vegetables and fruits by high-performance liquid chromatography (HPLC). Muir et al. (2009), J. Agricultural and Food Chemistry 57(2):554-565.
- Quantification of fructans, galacto-oligosaccharides and other short-chain carbohydrates in processed grains and cereals. Biesiekierski et al. (2011), J. Human Nutrition and Dietetics 24(2):154-176.
- Dietary sorbitol and mannitol: food content and distinct absorption patterns between healthy individuals and patients with irritable bowel syndrome. Yao et al. (2014), J. Human Nutrition and Dietetics 27(Suppl 2):263-275.
- FODMAPs: food composition, defining cutoff values and international application. Varney et al. (2017), J. Gastroenterology and Hepatology 32(Suppl 1):53-61. Supplies the low, moderate and high cutoffs used on this page.
Informational only, not medical advice. Individual tolerance varies. Talk to a healthcare professional or a dietitian for personal guidance.