A Scientific Comparison: Red, Green and Black Lentils

Lentils (Lens culinaris) are among the oldest domesticated foods in the world — their remains have been found at 11,000-year-old sites in the Middle East, and they are mentioned in the Book of Genesis in the story of Jacob and Esau’s lentil stew. They are also one of the most nutritionally efficient legumes: cheap, relatively quick to cook, and they provide protein, fiber and iron in a single serving.

Red lentils are also sold as Red Split Lentils or Split Red Lentils. Despite the name, they are orange — in Hebrew they are called “עדשים כתומות” (orange lentils) as well as “עדשים אדומות” (red lentils), both meaning the same thing. The full table of names below also covers green, brown, black and Puy lentils.

The different colors aren’t just a matter of looks — they point to differences in the skin, the texture and the cooking time. But as detailed below, the nutritional differences between them are much smaller than the culinary ones.

Red lentils, split lentils and other names on the package

Lentil is the name of the legume; red lentils are the orange ones. A package of split red lentils will sometimes say Split red lentils or Red split lentils. These are lentils whose skin has been removed and whose seed has been split; they cook faster than whole lentils and are suited to soups and purées. Source: Lentils.org, types of lentils.

Lentils — carbohydrate or protein?

This is the most common question, and the answer: lentils are a legume, so they’re both — but in terms of calorie contribution, they’re mainly carbohydrate.

Per 100 grams of cooked lentils:

Two important caveats that change the picture:

1. About 40% of the carbohydrates are fiber (7.9 out of 20.1 grams) — fiber isn’t absorbed and doesn’t raise blood sugar. The carbohydrate actually available is about 12 grams per 100 grams, significantly lower than rice or potato.
2. 9 grams of protein per 100 grams cooked is a very high amount for a plant food — more than in quinoa and similar to chickpeas.

In dietary meal plans, lentils are classified as a legume — a category considered both a carbohydrate source and a protein source at the same time. In a vegetarian diet they fill both roles.

Protein quality: Lentil protein is rich in lysine and low in methionine; grains are the opposite. That’s why the traditional combination of lentils with rice — mujadara, dal with rice, khichdi — creates a complete amino acid profile. The combination doesn’t have to be in the same meal, just over the course of the day.

1. Red/Orange Lentils (Red Lentils)

Lentils whose skin has been removed and that have been split in two. The orange color is the color of the inside of the seed.

• Benefits:
  • Speed: They cook within 15–20 minutes without soaking. The “fast food” of legumes.
  • The easiest to digest: Without the skin, they contain less insoluble fiber and fewer of the oligosaccharides that cause gas. This is the most suitable choice for people who get bloated from legumes, for babies and for those recovering from illness.
  • Texture: They break down completely and form a purée — ideal for thick soup, Indian dal and spreads.
• Downsides:
  • Less fiber: Removing the skin removes a considerable share of the fiber.
  • Higher glycemic index: Because they break down and are digested faster, the glycemic response is slightly higher than that of lentils with skin — still low compared with other starchy foods.
  • They don’t hold their shape: Not suitable for salads.

2. Green/Brown Lentils

The classic and most common lentil — “mujadara lentils.” The whole seed with its skin.

• Benefits:
  • The most fiber: The skin is kept, and with it most of the dietary fiber.
  • The cheapest in most stores.
  • Versatility: They hold their shape in most cooking, but release enough starch to thicken a stew.
  • Especially low glycemic load thanks to the skin.
• Downsides:
  • Long cooking time: 30–45 minutes, preferably with soaking in advance.
  • More gas: The skin and the oligosaccharides cause more digestive discomfort. Soaking, changing the cooking water and gradual adaptation reduce this significantly.

A premium variation: French Puy lentils — small green-gray lentils from the Le Puy region, with an especially firm texture and a mineral flavor. They are more expensive, and behave in the kitchen like black lentils.

3. Black Lentils (Black Beluga Lentils)

They are called “beluga” because of their resemblance to caviar.

• Benefits:
  • Anthocyanins: The black pigment is an anthocyanin — the same family of antioxidants found in blueberries and dark grapes. This is the only significant nutritional difference between the types of lentils.
  • Perfect texture: They keep their shape and bite even after full cooking — the best choice for cold salads and side dishes.
  • A deeper nutty flavor than the other types.
• Downsides:
  • Price: 2–3 times more expensive than green lentils.
  • Availability is more limited.
  • They stain light-colored dishes a purplish hue.

Comparison table

Values are for cooked lentils, per 100 grams. The figures vary between varieties and suppliers, and should be treated as a typical range rather than an exact number.

So which lentil is the healthiest?

The honest answer: the nutritional differences between the types of lentils are small, and they’re all excellent food. All the significant differences are culinary. But if you have to choose by goal:

• The most fiber and blood sugar balance: green/brown — the whole skin is the advantage.
• The most antioxidants: black, thanks to the anthocyanins.
• The easiest to digest and for people who suffer from gas: red.
• The most economical: green/brown.
• The quickest to prepare: red.

The best practical choice is to vary — not for nutritional reasons, but so that each dish gets the texture that suits it.

How to reduce gas from lentils

1. Soak green and black lentils for 4–8 hours (red lentils don’t need it).
2. Pour off the soaking water and cook in fresh water — the oligosaccharides that cause gas are water-soluble.
3. Skim off the foam that rises at the start of cooking.
4. Cook thoroughly until fully softened.
5. Start with red lentils and move gradually to types with skins.
6. Adaptation: Gut bacteria adapt within weeks of regular consumption, and symptoms decrease significantly.
7. Season with cumin or asafoetida — a traditional aid, and the effect is likely real.

An important cooking tip

Don’t add salt or acidic ingredients (tomatoes, lemon, vinegar) at the start of cooking lentils — they toughen the skin and significantly lengthen the cooking time. Add them only after the lentils have softened.

Summary and conclusions

Lentils are a legume that provides about 9 grams of protein and 8 grams of fiber per 100 grams cooked, with a low glycemic load and at a low price. In terms of calories they are mainly carbohydrate (about 67%), but about 40% of that carbohydrate is fiber that isn’t absorbed.

The difference between the colors is mainly culinary: red for soup, dal and easy digestion; green for mujadara, stews and the most fiber; black for salads, firm texture and antioxidants. Nutritionally, they’re all an excellent choice, and the differences between them are much smaller than people tend to think.