Food & Fit
Lentils have more protein per USDA household serving: 17.9 g in 1 cup (198 g), against 15.2 g in 1 cup (172 g) of black beans. It also carries more protein per 100 kcal: 7.8 g against 6.7 g.
Serving sizes, side by side
| Measure | Lentils | Black beans |
|---|---|---|
| Serving | 1 cup (198 g) | 1 cup (172 g) |
| Calories | 230 kcal | 227 kcal |
| Protein | 17.9 g | 15.2 g |
| Fiber | 15.6 g | 15 g |
| Carbohydrate | 39.8 g | 40.8 g |
| Fat | 0.8 g | 0.9 g |
| Protein per 100 kcal | 7.8 g | 6.7 g |
Read the numbers quickly
Each column keeps the food’s listed USDA household serving intact.
One cup of lentils lists 17.9 g protein and 15.6 g fiber, compared with 15.2 g protein and 15 g fiber for black beans.
How the servings stack up
Lentils
Its listed serving is 1 cup (198 g), the larger of the two. At 7.8 g protein per 100 kcal, it provides more protein within the same calorie amount than black beans.
Black beans
Its listed serving is 1 cup (172 g), the smaller of the two. At 6.7 g protein per 100 kcal, it provides less protein within the same calorie amount than lentils.
Explore each food
Lentils nutrition reference Black beans nutrition reference
Where these numbers come from
USDA descriptions: Lentils, mature seeds, cooked, boiled, without salt (FDC ID 172421); Beans, black, mature seeds, cooked, boiled, without salt (FDC ID 173735). Dataset: USDA FoodData Central, SR Legacy, April 2018 release, published 2019-04-01. Food records published 4/1/2019 and 4/1/2019; dataset retrieved 20 September 2026.
These USDA values give both foods a shared starting point; your own plate can be different.
- Written by
- Dr. Loredana Gavrilovici, Founder of Food & Fit
- Published