How much protein is there in 100g of black beans? A comprehensive guide.

November 8, 2025 •

3 min read

Did you know that the protein content in black beans changes dramatically depending on whether they are cooked or dry? While 100g of dry black beans contains around 22g of protein, the same amount of cooked beans offers about 8.9g, a crucial distinction when calculating your nutritional intake.

Quick Summary

The protein amount in black beans varies significantly with preparation, with dried beans containing much more per 100 grams than cooked or canned versions due to water absorption. This difference is important for dietary planning.

Key Points

Dry vs. Cooked: 100g of dry black beans contains about 22g of protein, while the same amount cooked contains about 8.9g due to water absorption.
Canned Options: Canned black beans contain less protein per 100g (around 6g) and often have higher sodium levels; rinsing can reduce sodium.
Rich in Fiber: Black beans are an excellent source of dietary fiber, which aids digestion, helps with weight management, and improves heart health.
Antioxidant Powerhouse: They contain high levels of antioxidants that protect cells and can lower the risk of chronic diseases.
Important Minerals: These beans are rich in essential minerals like iron, folate, magnesium, and potassium.
Complementary Protein: While not a complete protein on their own, pairing black beans with grains like rice or corn creates a complete protein profile.

The protein difference: Dry vs. Cooked Black Beans

When considering how much protein is in black beans, it is crucial to differentiate between their uncooked (dry) and cooked states. The primary reason for this variation is water content. When you cook dried black beans, they absorb a significant amount of water, which increases their weight and dilutes the concentration of all nutrients, including protein.

Protein in Dry Black Beans

For 100 grams of dry, mature seeds, black beans contain approximately 22 grams of protein. This high concentration makes them a dense source of plant-based protein before they are rehydrated and cooked. For those tracking macronutrients in their diet, this is an important figure to keep in mind, especially when preparing dried beans from scratch.

Protein in Cooked Black Beans

Once cooked, the protein per 100-gram serving decreases considerably due to the added water. Based on data from the USDA, a 100g serving of cooked black beans contains around 8.9 grams of protein. This is the figure most commonly referenced in nutrition databases for ready-to-eat servings.

Protein in Canned Black Beans

Canned black beans offer a convenient, ready-to-use option, but their nutritional content can vary. A typical 100g serving of canned black beans contains around 6 grams of protein, often with added sodium. Rinsing canned beans before use can help reduce the sodium content, but it will not significantly impact the protein amount. For canned beans, it is always recommended to check the nutrition label for the most accurate information.

The full nutritional spectrum of black beans

Beyond their protein content, black beans are a nutritional powerhouse, offering a wide array of other health benefits.

Fiber for digestive and heart health

Black beans are exceptionally high in dietary fiber, with 100g of cooked beans containing around 9 grams. The fiber, including both soluble and insoluble types, is beneficial for digestive health, and its presence helps lower LDL ("bad") cholesterol levels, supporting heart health. The high fiber and protein content also contribute to a feeling of fullness, which can aid in weight management.

Antioxidants and other key minerals

These beans are rich in antioxidants, particularly polyphenols and flavonoids, which protect cells from damage and may reduce the risk of chronic diseases like heart disease and cancer. They also contain important minerals and vitamins, including:

Iron: Crucial for energy production and carrying oxygen in the blood.
Folate (Vitamin B9): Essential for cell growth and DNA formation.
Magnesium: Involved in hundreds of biochemical reactions in the body.
Potassium: Important for maintaining normal blood pressure.

Comparison of protein content in legumes


Legume (Cooked)	Protein (per 100g)	Notes
Black Beans	8.9g	A reliable source of plant-based protein.
Soybeans	18.2g	Exceptionally high protein for a legume.
Lentils	9g	Similar to black beans, great for soups.
Chickpeas	14.5g (per cup) -> 8.4g (per 100g)	Great for hummus and salads.
Pinto Beans	9g	Comparable protein to black beans.
Kidney Beans	8.7g	Another common bean with good protein content.

Important considerations for preparation

Enhancing digestibility

Black beans contain anti-nutrients like phytates and lectins, which can interfere with mineral absorption and cause digestive discomfort. Fortunately, proper preparation can significantly reduce these effects.

Soaking: Soaking dried beans overnight helps reduce anti-nutrient levels and makes them easier to digest.
Rinsing: For canned beans, rinsing them thoroughly under cold water can reduce sodium content by a significant amount.
Cooking: Thorough cooking, especially boiling, is another effective way to break down anti-nutrients and ensure they are palatable.

Making a complete protein

While black beans provide a substantial amount of protein, they are considered an "incomplete" protein because they lack sufficient amounts of certain essential amino acids, namely methionine and cysteine. However, this is easily remedied by pairing them with grains like rice, corn, or quinoa throughout the day to form a complete protein profile.

Conclusion

The question of how much protein is there in 100g of black beans highlights an important distinction: the preparation method matters. With approximately 8.9g of protein per 100g when cooked, black beans serve as a valuable and economical source of protein for a balanced diet. Combined with their high fiber and rich mineral content, they offer substantial health benefits, making them a fantastic addition to various meals. By understanding the nutritional impact of different preparation methods, you can make informed choices to maximize the benefits of this versatile legume.

Frequently Asked Questions

100 grams of dry black beans contains approximately 22 grams of protein. After cooking, they absorb water, so 100 grams of cooked black beans contains around 8.9 grams of protein.

100 grams of canned black beans, which are already cooked, contains about 6 grams of protein. It is recommended to rinse canned beans to reduce sodium content.

No, black beans are not a complete protein on their own as they are low in certain essential amino acids (methionine and cysteine). However, combining them with a grain like rice makes a complete protein.

Soaking dried black beans is beneficial because it helps to reduce anti-nutrients like phytates and lectins, which can inhibit mineral absorption and cause digestive issues.

Black beans are rich in dietary fiber, antioxidants, and key minerals such as iron, folate, magnesium, and potassium. They can support heart health, digestion, and help manage blood sugar levels.

Yes, black beans can aid in weight loss. Their high fiber and protein content promote feelings of fullness, which can help reduce overall calorie intake.

You can reduce gas by incorporating black beans into your diet gradually, soaking dried beans for longer periods, or opting for sprouted beans. Rinsing canned beans can also help.

When cooked, black beans contain about 8.9g of protein per 100g, while cooked lentils contain a very similar amount, around 9g per 100g.