Protein head-to-heads · July 2026
Black beans (cooked) vs Lentils (cooked): which protein is cheaper?
USDA macros joined to current US grocery prices, reduced to the two numbers that decide it: dollars per gram of protein, and protein per calorie.
Lentils (cooked) is 1.1x cheaper per gram of protein ($0.022/g vs $0.025/g), while it also carries more protein per calorie (7.8 g vs 6.7 g per 100 kcal), so it wins on both axes.
| Food | $/g protein | 30 g protein costs | You need | kcal that come with it | Protein/100 kcal |
|---|---|---|---|---|---|
| Black beans (cooked) | $0.025 | $0.74 | 337 g | 445 kcal | 6.7 g |
| Lentils (cooked) | $0.022 | $0.67 | 333 g | 387 kcal | 7.8 g |
Full macros, per serving
| Food (per serving) | Price | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|---|
| Black beans (cooked) (100 g) | $0.22 | 132 | 8.9 g | 24 g | 0.5 g |
| Lentils (cooked) (100 g) | $0.20 | 116 | 9 g | 20 g | 0.4 g |
A week of protein from each
Hitting a common 100 g/day protein target from lentils (cooked) alone costs $15.56 a week; from black beans (cooked) alone, $17.30. That is a gap of $1.75 every week for the same protein. In practice you mix sources: the planner computes the cheapest mix for your exact target and calorie cap, live from the same dataset.
This one is not a trade-off
Lentils (cooked) is both the cheaper protein ($0.022/g against $0.025/g) and the leaner one (7.8 g protein per 100 kcal against 6.7 g). Most matchups force you to pick a side. This one does not, so black beans (cooked) has to win on taste, prep time or what else it brings to the meal, because it is not winning on the numbers.
The amount you actually have to eat
Thirty grams of protein means 337 g of black beans (cooked), and the other side is not much lighter. That is a real constraint, not a footnote: a price per gram only counts if the serving is one a person will finish. Treat black beans (cooked) as the base of a meal that other protein is added to, not as the protein itself.
What the calories cost you
Getting 30 g of protein from black beans (cooked) brings 445 kcal with it. On a 2,000 kcal day, three servings would be most of your budget before anything else goes on the plate. That is fine when you are eating at maintenance or building, and it is the reason this food falls apart on a cut no matter how good the price per gram looks.
Compare against other foods
- Black beans (cooked) vs Oats (dry)Lentils (cooked) vs Oats (dry)
- Black beans (cooked) vs Peanut butterLentils (cooked) vs Peanut butter
- Black beans (cooked) vs Tofu (firm)Lentils (cooked) vs Tofu (firm)
- Black beans (cooked) vs Whey protein (1 scoop)Lentils (cooked) vs Whey protein (1 scoop)
- Black beans (cooked) vs Greek yogurt (nonfat)Lentils (cooked) vs Greek yogurt (nonfat)
- Black beans (cooked) vs Eggs (~2 large)Lentils (cooked) vs Eggs (~2 large)
- Black beans (cooked) vs Chicken breast (raw)Lentils (cooked) vs Chicken breast (raw)
- Black beans (cooked) vs Canned tuna (in water)Lentils (cooked) vs Canned tuna (in water)
Frequently asked
- Which is cheaper for protein, black beans (cooked) or lentils (cooked)?
- Lentils (cooked), at $0.022 per gram of protein against $0.025 for black beans (cooked) (July 2026 US grocery prices). A 30 g protein serving costs $0.67 vs $0.74.
- Which has more protein per calorie, black beans (cooked) or lentils (cooked)?
- Lentils (cooked), with 7.8 g protein per 100 kcal against 6.7 g for black beans (cooked), 1.2x leaner. That matters when you are cutting and calories are the binding constraint.
- Which should I buy, black beans (cooked) or lentils (cooked)?
- Lentils (cooked) wins on both axes here: cheaper per gram of protein and more protein per calorie. Unless taste, prep or the rest of your macros say otherwise, it is the better default.
Prices are representative US grocery prices as of July 2026; your store will differ. Educational content, not medical or dietary advice. Dataset: free download, CC-BY.