The Ultimate Guide to Which Bean Has the Lowest Carb?

October 29, 2025 •

4 min read

While many beans are known for their high carbohydrate content, some varieties, like the black soybean, can have as little as 1 gram of net carbs per half-cup serving. Understanding this difference is crucial for anyone following a low-carb or ketogenic diet and seeking to determine which bean has the lowest carb count. This guide will provide a comprehensive look at the best low-carb bean options, their nutritional profiles, and how to enjoy them guilt-free.

Quick Summary

Black soybeans and green beans are the top choices for those seeking the lowest net carbohydrate content in beans, offering high protein and fiber with minimal carbs. Portion control is essential for any low-carb diet.

Key Points

Black Soybeans: These have the lowest net carbs, making them an excellent keto-friendly alternative for traditional beans.
Green Beans: Technically a pod, green beans are another very low-carb choice, working well as a vegetable side dish.
Net Carbs: To assess a bean's suitability for a low-carb diet, focus on net carbs, which accounts for indigestible dietary fiber.
Portion Control: Due to their carb content, even low-carb beans should be consumed in moderation, especially on a strict ketogenic diet.
Health Benefits: The high fiber in beans promotes gut health, and soybeans are a source of complete protein.
Preparation: Rinsing canned beans or soaking dried beans can help manage carb and sodium levels.
Check Labels: Always verify the nutritional information on specific bean products, as carb counts can vary by brand and processing.

Understanding Net Carbs in Beans

Before diving into specific varieties, it's essential to understand the concept of net carbohydrates. Net carbs are calculated by subtracting the grams of dietary fiber from the total carbohydrates. Fiber is a type of carbohydrate that your body cannot fully digest, so it has a minimal impact on your blood sugar levels and is often not counted towards your daily carb limit on restrictive diets like keto. Beans are naturally rich in fiber, which is why many have a significantly lower net carb count than their total carb count might suggest. The high fiber content also contributes to feelings of fullness, aids digestion, and can help regulate blood sugar levels.

The Winners: Black Soybeans and Green Beans

When comparing the carb content of different bean varieties, two clear winners emerge for those on a low-carb diet: black soybeans and green beans. These options provide excellent nutrition without a heavy carb load.

Black Soybeans: The Ultimate Low-Carb Replacement

For those who miss traditional beans in chili, soups, or refried bean dips, black soybeans are a game-changer. They function as a versatile replacement with an impressively low net carb count. A half-cup serving of canned black soybeans can contain as little as 1 gram of net carbs, though it is crucial to check the specific product's nutrition label for accuracy. They are also a fantastic source of plant-based protein and fiber. Their creamy texture makes them a perfect substitute for starchier beans in many recipes.

Green Beans: A Vegetable-Like Legume

Often enjoyed as a side dish, green beans (or string beans) are one of the most keto-friendly options available. While technically a legume, they are nutritionally closer to a vegetable and have a very low carb count. A full cup of green beans contains only about 4 grams of net carbs, along with a good dose of vitamins like Vitamin C and Vitamin K. Their versatility allows them to be roasted, sautéed, or added to casseroles.

Comparison of Carb Content in Common Beans

To provide a clear perspective, here is a comparison of net carbs for a variety of common beans. Please note that figures can vary slightly depending on the preparation and specific brand.


Bean Variety	Serving Size	Total Carbs (g)	Dietary Fiber (g)	Net Carbs (g)
Black Soybeans	½ cup	8	7	1
Green Beans	1 cup	7	3.4	~4
Edamame (shelled)	½ cup	8.9	6.7	6.7
Lupini Beans	½ cup	Varies	Varies	~1-6
Black Beans	½ cup	20.4	7.5	~13
Pinto Beans	½ cup	22.4	7.7	~15
Kidney Beans	½ cup	20.2	6.5	~14

Health Benefits of Low-Carb Beans

Beyond their low carb count, these beans offer numerous health advantages that make them a valuable addition to a balanced diet:

Rich in Fiber: The high fiber content, particularly in black soybeans, is beneficial for gut health by supporting good bacteria and promoting regular digestion.
High-Quality Protein: Soybeans are a complete protein source, meaning they contain all nine essential amino acids needed by the body. This is particularly valuable for vegetarian or vegan diets.
Packed with Vitamins and Minerals: Beans contain important nutrients like folate, manganese, and potassium. Folate is crucial for cell growth and is especially important during pregnancy.
Antioxidant Properties: Like many legumes, soybeans and green beans are a source of antioxidants, which help protect the body from cell damage caused by free radicals.

Practical Tips for Incorporating Low-Carb Beans

To maximize the benefits of low-carb beans while keeping your carb count in check, consider these tips:

Mindful Portioning

Even with low-carb beans, portion control is key, especially on a very strict ketogenic diet. While a small amount is fine, overindulgence could push you over your daily carb limit. A half-cup serving of black soybeans is a safe and satisfying amount for most.

Smart Preparation

Rinse Canned Beans: Canned beans often have high sodium levels. Rinsing them thoroughly under water can help remove excess sodium.
Soak Dried Beans: For dried beans, soaking them overnight before cooking can help reduce their carbohydrate content.
Check Labels: Nutritional values can vary between brands, especially for products like canned black soybeans. Always check the label to be sure.

Low-Carb Recipe Ideas

Use black soybeans as a base for a hearty, low-carb chili.
Sauté green beans with garlic and olive oil for a simple, flavorful side dish.
Blend black soybeans with seasonings and oil to create a keto-friendly refried bean alternative.
Roast green beans with parmesan cheese until crispy for a delicious snack.

Conclusion

While many people on low-carb diets avoid legumes, it is not necessary to give up beans entirely. The key lies in selecting the right varieties. Black soybeans and green beans are the clear frontrunners for anyone asking which bean has the lowest carb. Their excellent nutritional profile, including high fiber and protein, combined with their low net carb count, makes them a superb choice for supporting a healthy lifestyle. Remember to be mindful of portion sizes and preparation methods to ensure these healthy and satisfying legumes fit perfectly into your diet. For more information on legumes and their nutritional value, you can consult resources like Healthline's overview on soybeans.

Frequently Asked Questions

No, black soybeans are a different variety of legume from the more common black beans. Black soybeans have a much lower net carbohydrate count, making them a suitable substitute for low-carb or keto diets.

For dried beans, soaking them overnight can help reduce their carbohydrate content. For canned beans, rinsing them thoroughly can help remove excess starches and sodium.

Green peas are higher in net carbs than black soybeans and green beans but can be included in a low-carb diet in moderation. A half-cup serving contains approximately 3.2g of net carbs.

Chickpeas are relatively high in carbs for a strict low-carb plan, with around 8g net carbs per half-cup. They should be used sparingly if you are strictly limiting your carb intake.

Yes, black soybeans are an excellent substitute for traditional pinto or black beans when making low-carb refried beans or dips.

If beans are too high in carbs for your diet, alternatives include mushrooms, chopped eggplant, ground meat, or chopped nuts, depending on the recipe.

No, there can be significant variation in carb counts between different brands of black soybeans. It is always best to check the specific nutrition label on the product you purchase.