Soybeans top the list, delivering about 18.5 grams of protein per cooked cup. Among traditional beans, black beans, navy beans, and lentils cluster in the 15 to 18 gram range per cup, making them some of the most protein-dense plant foods available. The differences between varieties are meaningful enough to matter if you’re building meals around beans as a primary protein source.
Protein Content by Bean Variety
All protein counts below are for one cup of cooked or prepared beans, since that’s how you’ll actually eat them. Raw bean numbers look dramatically higher (black beans clock in at nearly 42 grams per raw cup), but cooking adds water and roughly doubles the volume, so the per-serving protein drops significantly.
- Edamame (young soybeans): 18.5 g per cup
- Lentils: 17.9 g per cup
- Black turtle beans: 15.1 g per cup
- Canned black beans: 14.5 g per cup
- Baked beans (canned): 13.1 g per cup
- Lima beans (baby, frozen): 12.5 g per cup
- Lima beans (boiled): 11.6 g per cup
Chickpeas, pinto beans, and kidney beans fall in the 12 to 15 gram range per cooked cup. At the bottom of the scale, green snap beans provide only about 2 grams per cup, which makes sense since they’re eaten for the pod rather than the mature seed inside.
Why Soybeans Stand Apart
Soybeans aren’t just higher in total protein. They’re also the only common legume that qualifies as a complete protein, meaning they contain all nine essential amino acids your body can’t make on its own. Soy protein scores a 1.00 on the PDCAAS scale, a measure of how well your body can absorb and use a food’s protein. That puts it on par with meat and dairy.
Other beans score considerably lower. Chickpeas and lentils both land at 0.52 on the same scale. That doesn’t mean their protein is useless. It means your body absorbs roughly half as effectively compared to soy or animal protein. The limiting factor for most beans is a shortage of sulfur-containing amino acids, particularly methionine. Grains happen to be rich in methionine, which is why beans and rice together form a more complete protein profile than either one alone.
You don’t need to combine them in the same meal. As long as you eat both grains and legumes over the course of a day, your body pools the amino acids and uses them as needed.
Canned vs. Dried Beans
There’s no meaningful difference in protein between canned and dried beans. The nutritional composition stays the same either way. Canned beans are more convenient, while dried beans give you more control over seasoning and sodium. If you’re using canned, rinsing them thoroughly can cut the sodium significantly without affecting protein.
The USDA data backs this up: canned black beans come in at 14.5 grams per cup, compared to 15.1 grams for home-boiled. That tiny gap likely reflects differences in the amount of liquid retained rather than any real nutritional change from the canning process.
Getting More Protein From Beans
If you’re relying on beans as a major protein source, a few practical choices make a real difference. First, favor the top performers. Swapping lima beans for lentils in a soup gains you about 6 extra grams of protein per cup with roughly the same cooking effort. Second, consider adding edamame to salads, grain bowls, or stir-fries where you might otherwise use a lower-protein bean.
Portion size matters too. A cup of cooked beans is a generous serving, roughly the size of a baseball. Most people eat closer to half a cup as a side dish, which cuts all the numbers above in half. If you’re aiming for 20 or more grams of protein per meal from beans alone, you’ll need a full cup or a combination of legumes with other protein sources like nuts, seeds, or whole grains.
For context, a cup of cooked lentils at nearly 18 grams of protein compares favorably to two large eggs (about 12 grams) or a cup of milk (8 grams). It falls short of a palm-sized portion of chicken breast (around 30 grams), but beans also bring fiber, iron, and folate that animal proteins don’t provide. Two cups of lentils in a day gets you to roughly 36 grams of plant protein, covering a substantial chunk of most adults’ daily needs.
Lentils vs. True Beans
Lentils are technically a different type of legume, not a bean, but most people searching for high-protein beans are thinking broadly about the legume family. At 17.9 grams per cooked cup, lentils consistently outperform most true bean varieties. They also cook faster than dried beans (about 20 to 30 minutes with no soaking required), which makes them one of the easiest high-protein legume options for weeknight meals.
Red lentils break down into a creamy texture when cooked, making them ideal for soups and dals. Green and brown lentils hold their shape better for salads and grain bowls. The protein content is similar across varieties.