Is soy sauce full of carbs? An in-depth nutritional guide

January 4, 2026 •

4 min read

According to USDA data, a single tablespoon of regular soy sauce contains less than one gram of carbohydrates, debunking the myth that it is full of carbs. However, the answer for whether soy sauce is a good fit for your diet depends on the type, serving size, and dietary goals, particularly for those on low-carb or ketogenic plans.

Quick Summary

Most soy sauce is very low in carbs, with traditional varieties containing less than 1g per tablespoon. Specialty sauces with added sugars can increase carb count, so reading the label is crucial, especially for keto diets.

Key Points

Low Carb Count: A single tablespoon of regular soy sauce contains less than one gram of carbs due to fermentation.
Check for Added Sugar: Dark and sweet soy sauces are higher in carbs because of added molasses and sugar, so check labels carefully.
Tamari is Gluten-Free: Tamari is a gluten-free soy sauce alternative with a comparable, but slightly higher, carb count.
Consider Alternatives: Options like soy liquid aminos are virtually carb-free, while coconut aminos are higher in carbs but soy-free.
Watch the Sodium: Soy sauce is extremely high in sodium, with a single tablespoon containing nearly 900mg; low-sodium versions are recommended.
Suitable for Keto in Moderation: Due to its low carb count per serving, regular soy sauce is generally acceptable on a keto diet when used sparingly.

The carb content of different types of soy sauce

When considering if soy sauce is full of carbs, it is essential to differentiate between the various types available. The fermentation process is key to why traditionally brewed soy sauce ends up with a low carbohydrate count, despite being made from soybeans and wheat. The yeasts and bacteria consume the starches and sugars during fermentation, converting them into alcohols and other compounds. This leaves a final product with very few residual carbs.

Regular Soy Sauce (Shoyu)

Traditional Carb Content: A standard tablespoon (about 15-16ml) of regular, traditionally brewed soy sauce contains approximately 0.8 to 1 gram of total carbohydrates.
Serving Size Impact: Because it is used in small quantities, a standard serving adds a negligible amount of carbs to a meal.
Fermentation Effect: The extensive fermentation process breaks down most of the wheat's carbohydrates, leaving behind a low-carb condiment.

Tamari

Gluten-Free Alternative: Tamari is a Japanese soy sauce variety that is often produced without wheat, making it a popular gluten-free choice. Some brands may use a small amount of wheat, so label checking is necessary for strict gluten avoidance.
Carb Count: Its carb count is similar to or slightly higher than regular soy sauce. Per tablespoon, it typically contains about 1.2 grams of carbohydrates.
Flavor Profile: Tamari is known for its darker color and richer, more balanced umami flavor.

Dark and Sweet Soy Sauces

Added Sugars: Unlike traditional soy sauces, dark soy sauce and especially sweet soy sauce (kecap manis) often have molasses, caramel color, or other forms of sugar added post-fermentation.
Higher Carb Count: This addition of sugar drastically increases the carbohydrate content, making these varieties unsuitable for low-carb or keto diets. Some sweetened sauces can contain up to 5 grams of carbs per tablespoon.
Use with Caution: Always read the nutrition label on these specialty versions to avoid hidden sugars that can throw off your macros.

Low-carb soy sauce alternatives

For those who need to strictly limit their carbohydrate intake, or have a soy or gluten allergy, several excellent alternatives exist.

Liquid Aminos

Two Types: Liquid aminos are made from either soybeans or coconuts.
Soy-Based: The soy-based version has a carb count very close to zero, or less than 1 gram per tablespoon, making it a strong contender for low-carb diets.
Coconut Aminos: Made from the fermented sap of coconut blossoms, this alternative is both soy-free and gluten-free. It has a sweeter, less salty flavor and contains more carbohydrates than regular soy sauce, with around 6 grams of carbs per tablespoon.

Fish Sauce

Umami Flavor: Fish sauce is another condiment that delivers a salty, umami kick. It is a popular staple in Southeast Asian cuisine.
Low Carb: Like soy sauce, it is low in carbohydrates, typically containing 1 gram or less per tablespoon. Some brands may add a small amount of sugar, so checking the ingredients is still recommended.

Dried Mushroom Powder or Broth

Zero-Carb Option: A very low-carb or zero-carb way to add umami flavor is by using dried mushroom powder or a broth made from dried mushrooms. This is an ideal alternative for very strict ketogenic diets.

Soy sauce carbohydrate comparison

To help visualize the difference in carb content, here is a comparison table of various types of soy sauces and common alternatives based on a 1-tablespoon serving.


Product	Approximate Total Carbs per Tbsp	Notes
Regular Soy Sauce	0.8–1 g	Contains wheat, but fermentation reduces carb load. High in sodium.
Tamari	1.2 g	Typically gluten-free, with a richer flavor profile.
Dark Soy Sauce	~2–5 g	Often contains added sugars and caramel for color and sweetness.
Sweet Soy Sauce (Kecap Manis)	~5+ g	Not low-carb; contains a high amount of added sugar.
Soy Liquid Aminos	~0 g	Very low carb, gluten-free, and soy-based.
Coconut Aminos	~6 g	Soy-free and gluten-free, but higher in sugar and carbs.
Fish Sauce	<1 g	Contains minimal carbs, but is not vegetarian.

The high sodium consideration

While the carb count of traditional soy sauce is minimal, its extremely high sodium content should be a primary concern for those watching their blood pressure or electrolyte balance on a diet like keto. A single tablespoon can contain over 900mg of sodium, or more than a third of the recommended daily intake. This makes choosing a low-sodium version a wise choice for many individuals.

Conclusion

In conclusion, traditional soy sauce is not full of carbs and can be included in moderation on most low-carb and ketogenic diets due to its low carbohydrate content. The key is to be a vigilant label reader, especially when considering dark or sweet varieties which contain high amounts of added sugar. For those with gluten or soy allergies, or those following a very strict low-carb regimen, excellent alternatives like tamari, soy liquid aminos, and fish sauce provide comparable flavor with little to no carbohydrate impact. Ultimately, enjoying this savory condiment responsibly is about portion control and choosing the right type for your dietary needs. For more information on food nutrition, refer to the USDA database.

Frequently Asked Questions

A standard tablespoon of regular soy sauce contains less than one gram of total carbohydrates, typically around 0.8 grams.

Yes, regular soy sauce is considered keto-friendly in moderation because its carb count per serving is very low. However, you should still be mindful of the high sodium content.

Yes, tamari contains a small amount of carbs, usually around 1.2 grams per tablespoon. It is often a gluten-free alternative to regular soy sauce.

Yes, dark and sweet soy sauces typically have added sugars like molasses, which significantly increases their carbohydrate content compared to regular soy sauce.

Soy liquid aminos are an excellent low-carb and gluten-free alternative, containing virtually no carbohydrates per tablespoon.

Fermentation with yeast and bacteria consumes the majority of the sugars and starches from the wheat and soybeans, which is why the final product is so low in carbs.

Besides carbohydrates, the most important factor is the very high sodium content, which can impact blood pressure and water retention. Opting for low-sodium versions is often recommended.

Soy sauce does contain sodium and phytoestrogens, but for most people, the small amounts consumed do not pose a significant health risk when used in moderation within a balanced diet.