Low Carb Keto Spaghetti Sauce (Marinara Pasta Sauce)

This keto marinara sauce will be your favorite low carb keto spaghetti pasta sauce! With a chunky texture, sweet flavor, and no added sugars, what's not to love?

By Maya Krampf
Published April 5, 2022

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Keto marinara spaghetti sauce in a dutch oven with fresh basil ribbons and spoon.

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I have so many recipes that call for a keto marinara sauce without added sugar, and while there are store-bought options available, many readers have asked me how to make it at home. So, here it is: The perfect, easy low carb keto spaghetti sauce!

While this sauce is certainly a classic choice for keto pasta, zucchini noodles, and even zucchini spaghetti, there are many other ways to enjoy it beyond just a keto pasta sauce. Keto pizza is a common use for it, but the sauce is cooked, unlike a regular keto pizza sauce. I also have a full list of other uses at the bottom of this post.

Many spaghetti sauces use sugar to balance the acidity from tomatoes. Instead of sugar, I’m using my favorite all-purpose sweetener: Besti Monk Fruit Allulose Blend! Since it measures and tastes like sugar (but contains 0 grams of net carbs), it’s perfect for sauces. Most importantly, it dissolves easily — unlike most substitutes — so your sauce will have no gritty texture.

Jar of low carb spaghetti sauce with Besti monk fruit sweetener.

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Is Spaghetti Sauce Keto?

Many spaghetti sauces are not keto friendly, as they have added sugar. Brands without added sugar are fine to use — as is this this keto low carb pasta sauce recipe. Of course, spaghetti itself is high in carbs, but you can serve it over low carb noodle alternatives.

Why This Is My Best Keto Spaghetti Sauce Recipe

Slightly sweet and super fresh flavor
Chunky texture — or puree to make it smooth
Easy to make (just 5 minutes prep)
Simple, healthy ingredients
Versatile — you can use this in so many ways!
Just 3.7 grams net carbs per generous serving (1/4 cup)
Healthy, gluten-free, keto-friendly, low carb, paleo, vegetarian, vegan

Keto spaghetti sauce in dutch oven with basil leaf garnish.

Ingredients You’ll Need

This section explains how to choose the best ingredients for keto friendly marinara sauce, what each one does in the recipe, and substitution options. For measurements, see the recipe card below.

Olive Oil – I prefer extra virgin olive oil, but regular olive oil or avocado oil are also fine.
Onion – I used white onion, but yellow onion will also work. If you want to reduce carbs more, you can substitute about 1 teaspoon of onion powder, to taste (add with the other spices).
Garlic – Use fresh garlic for best flavor, or jarred garlic for convenience. You can substitute 1/4 to 1/2 teaspoon of garlic powder, but fresh tastes better.
Crushed Tomatoes – These are typically canned or jarred. Make sure there aren’t any added sweeteners or other ingredients. Some brands list only crushed tomatoes, others have a blend of crushed tomatoes and either tomato puree or tomato sauce; any of these should work fine, but you do want crushed tomatoes as one of the ingredients.
Besti Monk Fruit Allulose Blend – This is the closest alternative to sugar that will give your sauce subtly sweet flavor without the carbs. Most importantly, it dissolves easily, so there’s no gritty texture. If you have Powdered Besti on hand instead, that’s also fine to use. Other powdered sugar substitutes would work, but they often crystallize when you store them.
Spices – Italian seasoning (which is a blend of oregano, marjoram, basil, thyme, rosemary, and sage), sea salt, black pepper, and red pepper flakes.
Fresh Basil – I prefer fresh here, but if you need to, you can substitute 2 teaspoons of dried basil in place of the 2 tablespoons fresh.

VARIATIONS: Add meat or veggies!

To make keto spaghetti meat sauce, add ground beef after onions and garlic are done sautéing. Or sneak in some sauteed keto vegetables for more nutrition.

Ingredients to make low carb pasta sauce.

How To Make Keto Pasta Sauce

This section shows how to make keto marinara sauce, with step-by-step photos and details about the technique, to help you visualize it. For full instructions, including amounts and temperatures, see the recipe card below.

Saute. Heat olive oil in dutch oven or pot over medium-high heat. Saute onion and garlic until soft and translucent.
Simmer. Add crushed tomatoes, Italian seasoning, salt, pepper, red pepper flakes (if using), Besti, and chopped basil. Stir together and simmer for 20 minutes.

Dutch oven with sauteed onion and garlic.

Low carb pasta sauce ingredients in a dutch oven.

Season. Add salt and pepper to taste.
Serve. Serve right away (see list of ideas below), or let the sauce cool before storing it in glass jars.

Cooked sugar-free keto marinara sauce close up.

Storage Instructions

Store: Keep low carb marinara sauce in glass jars in refrigerator for 3-5 days.
Reheat: Reheat the sauce in a saucepan or microwave, until hot.
Freeze: Freeze sauce in an airtight container for up to 2-3 months.

Spooning keto pasta sauce over zucchini noodles.

What To Serve With Keto Marinara Sauce

Wondering how to enjoy this homemade keto spaghetti sauce? I’ve got plenty of ideas. I’m sharing the top low carb noodle options below, but I’ve got even more in my keto pasta alternatives article.

Low Carb Noodles:

Zucchini Noodles – While sauce is simmering, make zucchini noodles and serve sauce over the top. (Don’t forget the parmesan!)
Spaghetti Squash – The baked spaghetti squash is hands off and easy to prep ahead, but microwave spaghetti squash is even quicker. Serve sauce on the spaghetti squash.
Shirataki Noodles – Shirataki noodles will be closest to spaghetti, but you have to cook them correctly! Be sure to follow the outlined steps.
Keto Egg Noodles – If you love chewy, thicker pastas like linguine or fettuccine, keto egg noodles are a delicious option.

More Ways To Use Low Carb Marinara:

Casseroles – You can use this recipe for keto spaghetti sauce in any casseroles or one-pot meals that call for marinara or spaghetti sauce. Try zucchini lasagna, cabbage roll casserole, Crock-Pot sausage and peppers, or eggplant lasagna.
Pizza – Use this sauce as a pizza sauce on classic keto pizza crust, cauliflower pizza crust, or zucchini crust. (For a simpler no-cook sauce option, use keto pizza sauce instead.)
Other Italian Dishes – Marinara sauce adds great flavor to an Italian dish. Try it in eggplant rollatini, Italian sausage stuffed mushrooms, or zucchini pizza boats.
On The Side – Marinara makes a wonderful dipping sauce for cauliflower breadsticks, roasted eggplant, or zucchini fries.

More Easy Low Carb Pasta Sauce Recipes

If you like this low carb spaghetti sauce recipe, you might also like some of these other sauce recipes:

Recommended Tools

Dutch Oven – I recommend making this low carb spaghetti sauce in a Dutch oven, since it heats up so well. Plus, it’s a kitchen work horse for so many other dishes, including one-pot meals.
Glass Jars – Store any leftover low carb pasta sauce in these glass jars that can also be frozen. Leave space at the top, as the sauce will expand.

Low Carb Spaghetti Sauce (Pasta Sauce) Recipe

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