Are you allowed soy sauce on a keto diet? The Complete Guide

November 9, 2025 •

5 min read

With only about 0.8 grams of carbs per tablespoon, traditional soy sauce appears to fit into a ketogenic diet at first glance. However, determining if you are allowed soy sauce on a keto diet depends on the specific product and your dietary approach.

Quick Summary

The keto-friendliness of soy sauce is not a simple yes or no, as some varieties contain added sugars or gluten. Understanding the nuances between different types and exploring low-carb alternatives is key to staying in ketosis.

Key Points

Moderate Use of Standard Soy Sauce is OK: Standard soy sauce has low enough carbs per tablespoon to be used sparingly, but check labels for added sugars.
Beware of Hidden Sugar: Sweet and dark soy sauce varieties often contain added sugar or molasses, making them unsuitable for a ketogenic diet.
Traditional Soy Sauce Contains Gluten: Regular soy sauce is fermented with wheat and contains gluten, which is not appropriate for a clean keto diet or those with sensitivities.
Tamari is a Gluten-Free Alternative: Tamari is a soy-based, gluten-free option, but it is not suitable for those who avoid soy.
Coconut Aminos are Soy and Gluten-Free: This alternative is made from coconut sap, offering a slightly sweeter flavor with lower sodium content compared to soy sauce.
Always Check the Label: Read the nutrition facts and ingredient list carefully to avoid hidden carbs, especially when choosing low-sodium or specialty sauces.
Other Umami Alternatives Exist: Fish sauce and dried mushrooms are other carb-free options for adding savory umami flavor to keto dishes.

The Nuanced Verdict on Traditional Soy Sauce

The simple answer to if you are allowed soy sauce on a keto diet is a conditional yes, primarily when used in moderation. The carb count is low enough that small amounts are unlikely to throw you out of ketosis. A typical tablespoon contains less than one gram of carbohydrates, making it a viable option for many who follow a less strict or "lazy" keto approach. However, several factors make it a less-than-ideal choice for those on a "clean" ketogenic diet or with specific health concerns.

Potential Hidden Risks in Conventional Soy Sauce

Not all soy sauces are created equal. Some varieties pose significant risks to those adhering to a strict keto or low-carb lifestyle. It's crucial to read the label and be aware of these potential pitfalls.

Added Sugars and Sweeteners: Sweet soy sauce and some dark soy sauces contain added molasses or sugar to thicken them and enhance their flavor. These varieties can contain up to five grams of carbs per tablespoon, quickly derailing your daily carb limit.
Gluten Content: Traditional soy sauce is typically fermented with both soybeans and wheat. This means it contains gluten, which is not suitable for those with celiac disease, gluten sensitivity, or those following a gluten-free version of the keto diet. Tamari, a Japanese variety, is often brewed without wheat but should still be checked for a gluten-free label.
Processed Ingredients and GMOs: Many conventional soy sauce brands are made with genetically modified (GMO) soybeans. For those prioritizing whole, unprocessed foods on a clean keto diet, this is a major drawback.
Phytoestrogens and Phytic Acid: Soybeans contain phytoestrogens and phytic acid. While the fermentation process reduces their levels in soy sauce, some keto advocates recommend avoiding soy due to potential hormonal impacts and interference with mineral absorption.
High Sodium Content: Soy sauce is notoriously high in sodium, with a single tablespoon containing a large portion of the recommended daily intake. While some sodium is beneficial during the keto flu transition, excessive intake is linked to elevated blood pressure. Opting for a low-sodium version is a better choice, but be mindful that some low-sodium versions can contain a bit more carbs.

Keto-Friendly Alternatives to Soy Sauce

For those seeking a safer, cleaner, or simply different savory flavor, there are several excellent low-carb alternatives that replicate the umami punch of soy sauce without the associated risks.

Coconut Aminos Made from fermented coconut palm sap and salt, this is a popular substitute for those who are soy-free and gluten-free. It has a milder, sweeter flavor profile and significantly less sodium than traditional soy sauce. Be aware that it has a slightly higher carb count than soy sauce per tablespoon (around 3g).

Tamari Sauce Often a gluten-free soy sauce, tamari is richer and has a deeper umami flavor than regular soy sauce. It is still soy-based, so it's not suitable for those avoiding soy, but it's a solid choice for those with gluten sensitivities.

Liquid Aminos Bragg Liquid Aminos are a soy-based, unfermented seasoning that is gluten-free. This option often has zero carbs per serving, providing a strong savory flavor. It is, however, still derived from soybeans.

Fish Sauce For a completely different, yet intensely savory umami flavor, fish sauce is an excellent, nearly carb-free option. It is made from fermented fish and salt and is a staple in many Southeast Asian cuisines. Use with caution due to its strong flavor and high sodium content.

Choosing the Right Condiment for Your Keto Diet

Choosing the best option depends on your specific keto goals and dietary needs. The following table provides a side-by-side comparison to help you decide.


Condiment	Key Ingredients	Gluten-Free?	Soy-Free?	Net Carbs (per tbsp)	Flavor Profile	Key Considerations
Traditional Soy Sauce	Soybeans, wheat, salt	No	No	~0.8g	Salty, umami	Contains gluten and higher sodium
Tamari Sauce	Soybeans, salt	Yes (if labeled)	No	~1g	Rich, deep umami	Still contains soy; higher sodium
Coconut Aminos	Coconut sap, salt	Yes	Yes	~3g	Milder, sweeter, less salty	Higher carbs; potentially sweeter flavor
Liquid Aminos	Soybeans, water	Yes	No	~0g	Savory, salty, less complex	Still contains soy; potentially high sodium
Fish Sauce	Fish, salt	Yes	Yes	~1g	Intense, pungent, salty	Strong flavor; higher sodium

When you're shopping, always check the nutritional information and ingredient list on the label. Many versions of soy sauce and its alternatives exist, and manufacturers can add hidden sugars or other non-keto ingredients.

Cooking with Keto-Safe Savory Condiments

Once you’ve chosen your preferred keto-friendly condiment, you can use it in a variety of ways to enhance your cooking. Proper usage is important to maximize flavor while adhering to your macros.

Marinades: Use any of the alternatives to marinate meat, fish, or tofu to add a deep, savory flavor. Adjust recipes that call for sugar by using a keto-friendly sweetener or simply omitting it.
Dipping Sauces: Create a quick, savory dipping sauce for sushi or other dishes by combining tamari or liquid aminos with a little toasted sesame oil and ginger.
Stir-fries: Enhance the flavor of keto stir-fries (using cauliflower rice or shirataki noodles) by adding your chosen soy sauce alternative to the pan. For extra richness, add some bone broth.
Soups and Stews: A small amount of tamari or liquid aminos can add depth and complexity to broths and stews without adding many carbs.

Conclusion: Making the Right Choice for Your Diet

So, are you allowed soy sauce on a keto diet? Yes, you can. However, a traditional soy sauce containing wheat is not suitable for a strict or clean keto diet. For the safest and cleanest approach, opting for a gluten-free and soy-free alternative like coconut aminos or tamari is recommended, especially for those with allergies or sensitivities. Moderation is key regardless of your choice, as all these condiments are high in sodium. By checking labels, understanding the differences, and exploring the many excellent alternatives, you can continue to enjoy rich, savory flavors while maintaining ketosis.

For more detailed nutritional information on these and other food items, you can reference resources like Nutritionix.

Frequently Asked Questions

No, traditional soy sauce is not gluten-free as it is typically made from a combination of fermented soybeans and wheat. For a gluten-free option, you should look for tamari sauce that is specifically labeled gluten-free.

Coconut aminos are often considered the best choice for a strict keto diet as they are both soy-free and gluten-free. Liquid aminos are another great option, with some brands having 0 carbs per serving.

Traditional soy sauce contains very little sugar, but certain varieties like sweet soy sauce and dark soy sauce may have added sugars or molasses, increasing their carb count significantly.

Coconut aminos are a soy-free, gluten-free, and lower-sodium alternative to soy sauce. However, they are slightly sweeter and higher in carbs per tablespoon (around 3g) compared to traditional soy sauce (around 0.8g), so portions still need to be monitored.

Yes, but you must still check the label carefully. Some low-sodium versions contain a higher carb count than regular soy sauce, so it's important to know what you are consuming.

Some people on a "clean keto" diet avoid soy due to concerns about GMOs, phytoestrogens, and phytic acid, which can interfere with mineral absorption and potentially affect hormone levels.

Yes, fish sauce is a great soy-free and low-carb alternative for adding a strong umami and salty flavor, though you may need to use less due to its intensity and high sodium content.