Lentils vs Black Beans: Macros, Nutritional Value, and Amino Acids

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I’ve done a general comparison of lentils vs beans, but I wanted to look specifically at how lentils stack up to black beans.

There are many reasons you might want to compare lentils to black beans.

So I did them all.

Somewhere on this page you should be able to find the difference between the 2 legumes that you’re looking for.

Whether it’s protein content, amino acid distribution, or nutritional value.

Macro Comparison: Lentils vs Black Beans

Let’s look at a high level breakdown for each legume.

The nutritional information for both is in 1 cup of cooked beans or lentils.

  Lentils Black Beans
Calories 230 227
Fat (g) 0.8 0.9
Carbohydrates (g) 39.9 40.8
Fiber (g) 15.6 15.0
Protein (g) 17.9 15.2

Clearly they’re very similar.

The biggest difference is that lentils have 2.7 extra grams of protein per serving. If you’re eating 2 or 3 cups of either, this difference adds up fast.

Other than that, they have about the same number of calories and fat, and black beans have a tiny bit more carbohydrates.

Essential Amino Acid Comparison

What about protein quality?

Here’s a breakdown of the essential amino acid content for both black beans and lentils.

  RDA RDA Black beans Lentils
  mg per kg for 70 kg person 1 cup 1 cup
Tryptophan (mg) 4 280 181 160
Threonine (mg) 15 1050 642 640
Isoleucine (mg) 20 1400 673 772
Leucine (mg) 39 2730 1218 1295
Lysine (mg) 30 2100 1046 1247
Methionine (mg) 15 1050 229 152
Phenylalanine (mg) 25 1750 824 881
Valine (mg) 26 1820 798 887
Histidine (mg) 10 700 425 503

As expected, they’re similar, but there’s one amino acid in particular I would like to highlight.

The typical essential amino acid profile of a bean is low in methionine.

Black beans have about 51% more methionine than lentils.

This isn’t a huge deal as long as your other protein sources have methionine. However, methionine is the most difficult essential amino acid to get from plants, so this is a little win for black beans.

Nutritional Value: Lentils vs Black Beans

I created a table below of just the vitamins or minerals that either legume were relatively high in.

All values are in % of the recommended daily value for each nutrient:

  Lentils (% DV) Black Beans (% DV)
Thiamin 22% 28%
Vitamin B6 18% 6%
Folate 90% 64%
Iron 37% 20%
Magnesium 18% 30%
Phosphorus 36% 24%
Potassium 21% 17%
Zinc 17% 13%
Copper 25% 18%
Manganese 49% 38%

Pretty similar as expected again, but there are some significant differences.

Lentils in general have more nutritional value than black beans, they have more in all but 2 of the above nutrients.

In particular, they have a lot more iron (37% vs 20%), which is probably the most important nutrient for someone eating a plant-based diet.

Which is Better: Black Beans or Lentils?

Putting that all together, we can make a few conclusions:

  • Lentils have a significant amount more protein than black beans.
  • Black beans have more methionine, an essential acid that most beans lack.
  • Both are great vitamin and mineral wise, but lentils have more overall, plus more of iron, potassium, and zinc (arguably the most important ones).

Overall, lentils have more nutritional value than black beans, so they’d be the winner if we had to declare one.

But they’re both great sources of nutrition and good sources of protein (especially for vegans).

About the author

Dale C.

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance writer. Trying to do my small part in making the world better by writing about the wonderful world of veganism.

3 comments

  • Thank you, exactly what I was looking for and the results are pleasant! But I have one question: are all lentils the same?

    • The data here came from the general nutrition data for “lentils”.

      If you look at different colors (i.e. red, brown, green), there are some small differences, but in general they’re almost identical nutritionally speaking.

      I do find red lentils taste different than brown or green (which both taste similarly), and red ones also cook faster. But other than that they’re quite similar.

      Here’s a brown lentils vs red lentils comparison if you’d like to see a detailed example.