Read the Cooking State Before You Read the Number
Legume nutrition numbers are the most misquoted figures in nutrition writing, and the reason is simple: dry beans absorb roughly two to three times their weight in water. USDA FoodData Central publishes both states, and the same bean can honestly be described as having 21.6g or 8.9g of protein per 100g depending on which entry you read.
Unless a recipe calls for weighing beans dry, the cooked figures are the ones that matter. Every table below is labeled explicitly.
Cooked Legumes, per 100g
These are the numbers to use when a recipe or a plate has already been cooked.
| Food (FDC ID) | Calories (kcal) | Protein (g) | Fiber (g) | Iron (mg) | Folate (µg) |
|---|---|---|---|---|---|
| Soybeans, cooked, boiled(174299) | 172 | 18.2 | 6.0 | 5.1 | 54 |
| Edamame, frozen, prepared(168411) | 121 | 11.9 | 5.2 | 2.3 | 311 |
| Beans, white, cooked, boiled(175203) | 139 | 9.7 | 6.3 | 3.7 | 81 |
| Beans, kidney (royal red), cooked, boiled(175197) | 123 | 9.5 | 9.3 | 2.8 | 74 |
| Lentils, cooked, boiled(172421) | 116 | 9.0 | 7.9 | 3.3 | 181 |
| Beans, pinto, cooked, boiled(173796) | 143 | 9.0 | 9.0 | 2.1 | 172 |
| Beans, small white, cooked, boiled(173750) | 142 | 9.0 | 10.4 | 2.8 | 137 |
| Beans, black, cooked, boiled(173735) | 132 | 8.9 | 8.7 | 2.1 | 149 |
| Chickpeas (garbanzo), cooked, boiled(173757) | 164 | 8.9 | 7.6 | 2.9 | 172 |
| Peas, split, cooked, boiled(172429) | 118 | 8.3 | 8.3 | 1.3 | 65 |
| Mung beans, cooked, boiled(174257) | 105 | 7.0 | 7.6 | 1.4 | 159 |
Source: USDA FoodData Central. Values are per 100g of cooked, drained legume.
🌾 See the full fiber ranking across all foods →Dry Legumes, per 100g
These are the figures behind most “beans have 22g of protein” headlines. They are accurate — for the uncooked seed.
| Food (FDC ID) | Calories (kcal) | Protein (g) | Fiber (g) | Iron (mg) | Folate (µg) |
|---|---|---|---|---|---|
| Lentils, raw(172420) | 352 | 24.6 | 10.7 | 6.5 | 479 |
| Mung beans, raw(174256) | 347 | 23.9 | 16.3 | 6.7 | 625 |
| Beans, kidney, red, raw(173744) | 337 | 22.5 | 15.2 | 6.7 | 394 |
| Beans, navy, raw(173745) | 337 | 22.3 | 15.3 | 5.5 | 364 |
| Beans, black, raw(173734) | 341 | 21.6 | 15.5 | 5.0 | 444 |
| Beans, pinto, raw(175199) | 347 | 21.4 | 15.5 | 5.1 | 525 |
| Chickpeas (garbanzo), raw(173756) | 378 | 20.5 | 12.2 | 4.3 | 557 |
Compare mung beans across the two tables: 23.9g protein dry, 7.0g cooked. Nothing was lost — 100g of dry mung beans becomes roughly 300g once cooked, so the nutrients are spread across three times the weight. Folate is the exception: it is water-soluble and heat-sensitive, so cooking genuinely reduces it (625µg dry to 159µg cooked, a larger drop than dilution alone explains).
Canned Beans: The Convenience Trade-off
| Food (FDC ID) | Calories (kcal) | Protein (g) | Fiber (g) | Iron (mg) | Folate (µg) |
|---|---|---|---|---|---|
| Beans, kidney, red, canned, drained(174285) | 124 | 8.0 | 5.5 | 1.5 | 28 |
| Beans, navy, canned(173747) | 113 | 7.5 | 5.1 | 1.9 | 62 |
| Beans, black turtle, canned(175188) | 91 | 6.0 | 6.9 | 1.9 | 61 |
Canned beans come in modestly lower on protein and fiber than home-cooked, and considerably lower on folate — canned red kidney beans show 28µg of folate against 149µg in home-cooked black beans. Sodium is the other consideration: draining and rinsing canned beans removes a meaningful share of the added salt. The convenience is often worth it; the trade-off is just worth knowing.
What Legumes Are Actually Best At
🌾 Fiber
Cooked small white beans deliver 10.4g of fiber per 100g and kidney beans 9.3g — against 0g in any meat, fish, egg or dairy product. A single cup covers roughly two-thirds of the 28g Daily Value.
🌿 Non-heme iron
Cooked white beans provide 3.7mg and lentils 3.3mg per 100g. This is non-heme iron, absorbed at roughly 2–20%, so pair it with a vitamin C source in the same meal — tomatoes, peppers, or a squeeze of lime all work.
🧬 Folate
Cooked lentils supply 181µg per 100g, about 45% of the 400µg Daily Value. Legumes are the densest plant folate source in the American diet.
💪 Complete protein (soy only)
Soybeans at 18.2g per 100g cooked are the one legume that both matches animal-protein density and supplies a complete amino acid profile. Other legumes are limited in methionine — pairing them with grains fills the gap.
Per Cup, Not Per 100g
Legumes are almost always measured by the cup in US kitchens. Converted to standard cup weights:
| Cooked legume | 1 cup | Protein (g) | Fiber (g) |
|---|---|---|---|
| Lentils | 198g | ~18 | ~16 |
| Black beans | 172g | ~15 | ~15 |
| Chickpeas | 164g | ~15 | ~12 |
| Pinto beans | 171g | ~15 | ~15 |
| Split peas | 196g | ~16 | ~16 |
| Mung beans | 202g | ~14 | ~15 |
Calculated from the per-100g cooked values above using standard USDA cup weights. One cup of almost any cooked legume lands near 15g of protein and 15g of fiber — over half the fiber Daily Value in a single side dish.
Key Takeaways
- ✓Cooked legumes cluster tightly: 7–10g protein and 6–10g fiber per 100g. Soybeans are the outlier at 18.2g protein.
- ✓Dry figures are roughly three times the cooked ones — dry mung beans 23.9g protein vs 7.0g cooked. Always check which state a number refers to.
- ✓Small white beans lead on fiber (10.4g per 100g cooked); white beans lead on iron (3.7mg); lentils lead on folate (181µg).
- ✓One cup of nearly any cooked legume delivers about 15g of protein and 15g of fiber.
- ✓Canned beans lose the most on folate (28µg for canned kidney vs 149µg for home-cooked black beans). Drain and rinse to cut added sodium.
- ✓Legume iron is non-heme — pair it with vitamin C in the same meal to improve absorption.
Related reading: Protein Per 100g Compared, Dietary Fiber-Rich Foods, Iron-Rich Foods, and Folate-Rich Foods.
Data Source
・USDA FoodData Central — Foundation Foods and SR Legacy
・FDA Daily Values (21 CFR 101.9)
This article is general nutrition information and is not intended to diagnose or treat any condition.