Lentils are too high in carbs for strict keto in normal portions. One cup of cooked lentils (198g) has about 40g of carbohydrate and 16g of fiber. Subtract the fiber and you have 24g of net carbs. A strict keto diet allows about 20g of carbs for the entire day, so a single cup takes all of it.
Small amounts are a different matter. Two tablespoons stirred into a salad cost about 3g, which most keto days can absorb.
Net carbs in lentils by serving size
Figures are for boiled lentils with no added ingredients, rounded from USDA FoodData Central.
| Serving (cooked) | Total carbs | Fiber | Net carbs | Protein |
|---|---|---|---|---|
| 1 cup (198g) | 40g | 16g | 24g | 18g |
| Half cup (99g) | 20g | 8g | 12g | 9g |
| Quarter cup (50g) | 10g | 4g | 6g | 4.5g |
| 2 tablespoons (25g) | 5g | 2g | 3g | 2g |
| 100g | 20g | 8g | 12g | 9g |
How much of your day that uses
Keto works by keeping carbs low enough that your body runs mainly on fat. Harvard's Nutrition Source describes the diet as under 50g of carbohydrate a day and as low as 20g. Most keto plans count net carbs, which is total carbs minus fiber.
| Your daily limit | 1 cup of lentils | Half cup | 2 tablespoons |
|---|---|---|---|
| 20g (strict keto) | 120% | 60% | 15% |
| 30g | 80% | 40% | 10% |
| 50g (liberal keto) | 48% | 24% | 6% |
At 50g a day, half a cup is workable if the rest of the day is meat, eggs, cheese and leafy vegetables. At 20g, it leaves you 8g for everything else you eat.
Lentils compared with other legumes
Most pulses land in the same range as lentils. The exceptions are soy and lupin, which store their energy as protein and fat.
| Half cup, cooked | Net carbs | Fits strict keto? |
|---|---|---|
| Chickpeas | 16g | No |
| Kidney beans | 14g | No |
| Black beans | 13g | No |
| Lentils | 12g | No |
| Green peas | 8g | Small portions |
| Edamame, shelled | 3g | Yes |
| Green beans | 3g | Yes |
| Black soybeans, canned | 1 to 2g | Yes |
| Lupini beans | 1 to 6g | Check the label |
Black soybean and lupini figures depend on the brand. USDA lists boiled lupins at about 6g of net carbs per half cup, while some brined, jarred brands label 1g.
Six swaps for the dishes you used lentils in
- Lentil soup: use canned black soybeans. They hold their shape in broth and taste close to black beans.
- Dal: cook finely chopped cauliflower with the same tempering of cumin, garlic, ginger and turmeric, then stir in two tablespoons of red lentils per serving for the flavor.
- Lentil salad: use shelled edamame or brined lupini beans.
- Lentil bolognese: use finely chopped mushrooms and walnuts, browned hard before the tomato goes in.
- Lentil burgers: use crumbled extra-firm tofu or tempeh bound with egg.
- A side of lentils: use sautéed green beans with butter and garlic.
When lentils are still worth eating
If you follow a moderate low-carb diet of 50 to 100g a day, lentils earn their place. Half a cup gives you 9g of protein, 8g of fiber, and useful amounts of iron and folate for 115 calories. People who cycle carbs or eat keto five days a week often put lentils on the higher-carb days for that reason.
For everything that does fit, see the keto diet food list. To set your own carb, fat and protein targets, use the calorie and macro calculator.
Sources
- USDA FoodData Central for carbohydrate, fiber and protein values (lentils, mature seeds, cooked, boiled, without salt, and the other legumes in the comparison table).
- Harvard T.H. Chan School of Public Health, The Nutrition Source, Diet Review: Ketogenic Diet for Weight Loss.
FAQ
Are lentils keto friendly?
A normal serving is too high in carbs for strict keto. One cup of cooked lentils has about 24g of net carbs, and strict keto allows about 20g for the whole day. A spoonful or two as a garnish fits, but a full bowl uses the whole allowance.
How many net carbs are in lentils?
Cooked lentils have about 12g of net carbs per 100g. That is 24g per cup (198g), 12g per half cup, 6g per quarter cup and about 3g per two tablespoons.
Are red lentils lower in carbs than green lentils?
No. Red, green, brown and black lentils all have close to 20g of total carbs per 100g cooked. Red lentils are split and hulled, so they have slightly less fiber, which makes their net carbs a touch higher.
Can I eat lentil soup on keto?
A standard bowl made with half a cup or more of lentils has 12g or more of net carbs before the carrots and onions. To keep the flavor, make the soup with black soybeans and add two tablespoons of lentils per bowl.
Are lentils OK on low carb if they are not keto?
Yes. On a moderate low-carb diet of 50 to 100g of net carbs a day, half a cup of cooked lentils at 12g is easy to fit, and it brings 9g of protein and 8g of fiber.
What beans can you eat on keto?
Black soybeans, edamame and green beans, which each have 3g of net carbs or less per half cup. Lupini beans range from 1 to 6g depending on the brand. Chickpeas, black beans and kidney beans have 13 to 16g per half cup and are too high for strict keto.