What is a keto substitute for cornstarch? Finding the best low-carb thickeners

November 1, 2025 •

4 min read

Did you know a single tablespoon of cornstarch can contain over 7 grams of net carbs, making it unsuitable for a strict keto diet? So, what is a keto substitute for cornstarch? The good news is that numerous low-carb alternatives exist for thickening sauces, soups, and gravies without compromising your nutritional goals.

Quick Summary

This guide explores effective keto-friendly thickeners, such as xanthan gum, glucomannan powder, and almond flour, detailing their properties and ideal uses. Compare how these substitutes work for thickening sauces and gravies in various cooking applications.

Key Points

Xanthan Gum: Use this zero-net-carb powder sparingly for thickening hot sauces, gravies, and dressings, mixing it with fat or liquid first to avoid clumps.
Glucomannan Powder: An even more powerful, zero-net-carb fiber than xanthan gum, it’s best for hot dishes and holds its consistency well upon reheating.
Guar Gum: Optimal for cold preparations like ice creams and dressings, as it is less effective in hot or acidic liquids.
Almond Flour: A useful option for thickening heartier sauces and gravies, or as a low-carb breading, though it will produce a less-smooth texture.
Cream Cheese: Ideal for thickening creamy soups and sauces, it also adds a rich flavor and velvety consistency.
Pureed Vegetables: For a whole-food approach, blend vegetables like cauliflower into soups and stews for a creamy, natural thickener.

For those following a ketogenic diet, finding suitable substitutes for high-carb ingredients is a constant challenge. Cornstarch, a common kitchen staple, is one of the first to be replaced due to its high carbohydrate count. Thankfully, a variety of effective, low-carb options can achieve the same thickening and binding results in your favorite recipes.

Low-Carb Thickening Gums and Powders

Xanthan Gum

Xanthan gum is a popular and potent thickener created by fermenting sugar with a specific bacteria. A very small amount goes a long way, making it an excellent choice for sauces, gravies, and dressings. It has zero net carbs and works quickly, even without heat. It is important to add it slowly to avoid a slimy texture and mix it with a small amount of liquid or fat first to prevent clumping.

Glucomannan Powder

Also known as konjac flour, glucomannan is a dietary fiber from the konjac plant. It is an exceptionally strong thickener that is tasteless and contains no net carbs. Like xanthan gum, it should be used sparingly. It thickens at lower temperatures than cornstarch, so it's best to mix it with cold liquid before adding it to your dish to avoid lumps. A key benefit is its ability to create a smooth, stable consistency that holds up well when reheated.

Guar Gum

Derived from guar beans, guar gum is a fiber-rich, low-calorie, and zero net carb thickener. While similar to xanthan gum, it has different properties; it is best used for cold applications like salad dressings and ice creams because it can lose some thickening power in acidic, hot liquids. It is also less potent than xanthan gum, requiring slightly more for the same effect.

Nut and Seed-Based Thickeners

Ground Flaxseed and Chia Seeds

Both ground flaxseeds and chia seeds form a gel when mixed with liquid, making them excellent binders and thickeners. While they do add a nutritional boost and fiber, their texture can be slightly gritty. They are particularly useful in recipes where a slightly nutty flavor and denser texture are welcome, such as in keto baked goods or jams.

Almond Flour

While not a primary thickener like gums, almond flour can add body to sauces and stews and act as a low-carb breading. It is made from finely ground, blanched almonds and has a mild flavor. Using almond flour for thickening will not yield the same smooth consistency as cornstarch and is better for creating heartier, thicker gravies rather than clear sauces.

Coconut Flour

Coconut flour is a very absorbent, fiber-rich option that can be used for thickening. Due to its high absorbency, it requires a significant amount of liquid and can create a grainy texture and introduce a distinct coconut flavor. It is often used in combination with other flours in keto baking rather than as a sole thickener for sauces.

Other Creamy Alternatives

Cream Cheese or Heavy Cream

For dairy-based sauces and soups, heavy cream and cream cheese are excellent thickeners that add richness and a creamy texture. Reducing cream by simmering can thicken a dish effectively, while cream cheese can be whisked in near the end of cooking for a smooth, velvety finish.

Pureed Vegetables

For a natural, whole-food approach, pureeing cooked vegetables can thicken soups and stews. Cauliflower is a neutral-flavored option that can be blended into a creamy base for sauces and chowders. Other options include pureed pumpkin or zucchini.

Comparison of Keto Cornstarch Substitutes


Thickener	Ideal Use Case	Texture	Ratio vs. Cornstarch	Best for…
Xanthan Gum	Hot/Cold applications, baked goods	Smooth, gelatinous	~1/4 to 1/2 tsp per tbsp	Sauces, gravies, dressings
Glucomannan	Hot sauces, gravies	Smooth, gel-like	Use sparingly (approx. 1/4 tsp per tbsp)	Gravies, soups, stable reheating
Guar Gum	Cold applications, dairy-based sauces	Smooth	~1/8 the amount of cornstarch	Ice cream, salad dressings
Ground Flaxseed	Baking, jams	Gritty	1 tbsp ground flax + 4 tbsp water per 2 tbsp cornstarch	Hearty baked goods, jams
Almond Flour	Stews, gravies, breading	Less smooth, gritty	Varies, use generously	Meaty sauces, breading
Cream Cheese	Creamy sauces, soups	Smooth, creamy	Varies, add to desired consistency	Dairy-based soups and gravies

Conclusion

While cornstarch is a convenient thickener, the ketogenic diet offers a superior array of low-carb alternatives with added nutritional benefits. For most hot sauces and gravies, xanthan gum and glucomannan powder are the most potent and reliable choices, yielding a smooth texture similar to cornstarch. For cold applications, guar gum is a better fit. Meanwhile, nut and seed flours offer a heartier, more textured option, and whole food methods like pureeing vegetables provide a natural thickening solution. Experimenting with these substitutes allows you to maintain the desired consistency in your keto dishes without sacrificing flavor or health goals.

For further reading on dietary fibers, consult the National Institutes of Health: National Institutes of Health (NIH) | (.gov)

Frequently Asked Questions

To prevent lumps with powdered thickeners like xanthan gum or glucomannan, mix them into a small amount of liquid or fat (like oil or melted butter) before adding them to your main dish. Whisk constantly as you incorporate the slurry into the hot liquid.

Since xanthan gum is a powerful thickener, you should start with a small amount. A typical ratio is about 1/4 to 1/2 teaspoon of xanthan gum for every tablespoon of cornstarch requested in a recipe.

Almond flour can thicken gravy, but it won't produce the same smooth, glossy texture as cornstarch or xanthan gum. It is better for creating a rustic, hearty consistency and is best used for thicker sauces rather than clear gravies.

Guar gum is a great choice for thickening cold foods and liquids, as it is most effective at cooler temperatures and works well as an emulsifier to prevent separation.

Yes, ground chia seeds and flaxseeds are excellent keto-friendly thickeners, as they are high in fiber and low in net carbs. Be aware they can add a slightly gritty texture and nutty flavor to your recipes.

Yes, heavy cream and cream cheese are great for thickening creamy soups and sauces on a keto diet. They add richness and a smooth consistency without the high carbohydrate load.

While often used as a gluten-free thickener, arrowroot powder is actually high in carbs and less suitable for a keto diet. Options like xanthan gum or glucomannan are much lower in net carbs and more aligned with keto macros.