Lentils are the legume that needs no planning.
No soaking, no twelve-hour decision, no bag at the back of the cupboard reproaching you. You can decide at six o’clock that dinner is lentils and be eating by half past.
They are also the food a famous piece of research is named after, and the one we recommend to anybody whose stomach has never got on with beans. Here is which kind to buy, how to cook each one, and what is actually in them.
The short answer: No lentil needs soaking. Rinse, cover with about three times their volume of water, simmer. Red split lentils collapse into a puree in 15 to 20 minutes. Brown and green hold their shape in 25 to 30 minutes, and Puy and beluga stay firm in about 25.
Buy red for soups and anything you want thick, and brown or green for anything you want to see. A cup of cooked lentils carries 17.9 g of protein and 16 g of fibre. Salt and acid go in at the end, never at the start, because both keep the skins tough.
Which Lentil to Buy
The colour on the bag tells you what the lentil will do in the pot, and that is genuinely the only thing you need to know at the shop.
Split lentils have had the skin removed, so there is nothing holding them together and they fall apart. Whole lentils keep their skin and hold their shape. Everything else follows from that.
| Lentil | Cooking time | What it does | Use it for |
|---|---|---|---|
| Red or yellow split | 15 to 20 minutes | Collapses completely | Soups, dal, anything you want thick without cream |
| Brown | 25 to 30 minutes | Holds, then softens | The everyday one. Stews, patties, stuffed vegetables |
| Green | 25 to 30 minutes | Holds its shape well | Salads, and anything you want to still see |
| Puy or French | 20 to 25 minutes | Stays firm and peppery | Cold salads. The most expensive and the least necessary |
| Black beluga | 20 to 25 minutes | Stays firm, turns glossy | When it needs to look like something |
If you only ever keep one, keep red split. They are the cheapest, the fastest, and they thicken a pot by themselves, which means no flour, no cream and no blender.
Our red lentil cream soup is fifteen minutes from a cold pan to a bowl and has no cream in it anywhere. That is the whole argument for the red ones in one recipe.
How to Cook Lentils
- Rinse them and pick them over. Lentils are field-harvested and a small stone gets through now and again. Tip them into a sieve, run water over them, and glance at what is there.
- 3 parts water to 1 part lentils. More if you want soup, less if you want them to stay separate. They do not need precision the way rice does.
- Simmer, uncovered, and skim the foam. 15 to 20 minutes for red split, 25 to 30 for the whole ones. Start tasting early, because a lentil goes from firm to collapsed faster than you expect.
- Salt and acid at the end. Not the start. This is the one rule that decides the texture.
Why lentils need no soaking
A chickpea or a kidney bean is large, dense and thick-skinned, so water takes hours to reach the middle. A lentil is thin and small, and water gets to the centre of one in minutes.
That is the entire difference. It is not that lentils are a different sort of food, it is that they are a thinner one.
You can soak them if you want, and it will take a few minutes off the cooking and a little off the gas that legumes cause. It is not required and we mostly do not bother.
The exception is the one where soaking is doing structural work rather than softening. Our lentil bread needs them soaked and still raw, because boiled lentils have already gelatinised and cannot set again in the oven. There is more on that in the flourless bread guide.
The rule that decides the texture
Salt and acid both firm up the skin of a legume. Added early, they will keep lentils chalky long past the point where they should have softened.
This is the usual reason lentils cooked in a tomato sauce never seem to get there. The tomatoes are the problem, not the lentils, and no amount of extra simmering will rescue it.
So cook them in plain water first, then add the tomatoes, the lemon and the salt once they are as soft as you want them. In our red lentil stew the lemon goes in off the heat at the very end, and it is what stops a pot of lentils tasting flat.
The Lentil Effect: Why Tonight’s Dinner Changes Tomorrow’s Breakfast
There is a phenomenon in nutrition research called the second-meal effect, and it was first described in 1982 using lentils. It is sometimes still called the lentil effect.
Researchers fed people lentils at dinner and then measured what happened to their blood sugar at breakfast the next morning, 11 hours later. The response to that breakfast was measurably better, and the breakfast itself was identical in both arms.
Why it happens
The mechanism is your gut bacteria. A large part of the carbohydrate in lentils never reaches your bloodstream at all. The fibre and resistant starch travel down to the colon, the bacteria there ferment them into short-chain fatty acids, and those enter the blood and slow gastric emptying and improve insulin sensitivity at the next meal.
Estimates for the size of it sit around a 20 to 30 per cent flatter glucose curve at the following meal.
Blending does not undo it. This is the part that surprises people, and it is worth knowing because it decides whether a smooth soup is a compromise.
Blend rice into a slurry and its glycemic index climbs to meet a potato’s. Blend lentils and nothing happens: whole, pureed and powdered all produce the same low response, because legume cell walls are thick enough to survive the processing.
So a creamy dal is just as flat a curve as a bowl of whole lentils. Our red lentil soups are not the lesser version of the food.
It is the reason we put lentils at lunch when the afternoon matters, and the reason a bowl of lentil soup holds us about 5 hours where a salad does not.
What Is Actually in a Cup of Lentils
| Per cup, cooked | |
|---|---|
| Protein | 17.9 g |
| Fibre | 16 g |
| Folate | 358 mcg, against an RDA of 400 |
| Fat | About 3 per cent of the calories |
The protein figure is worth sitting with, because it is the one people get wrong in both directions.
A cup of cooked lentils carries about 1.4 times the protein of a fried chicken drumstick. Not a similar amount. More.
It also arrives with 16 g of fibre and almost no fat, which the drumstick does not. We go through the whole question, including how much you actually need, in our guide to vegan protein.
One cup also puts you most of the way to the folate you need for the day, which matters more than it sounds, because folate is one of the few nutrients where the pill and the food behave differently.
What legumes do over a lifetime
Across five populations on different continents, eating soy in Japan, brown beans and peas in Sweden, lentils and chickpeas around the Mediterranean, legumes came out as the single most important dietary predictor of survival in older people.
Different legumes, different cultures, same result. It is one of the cleanest findings in the whole of nutrition and almost nobody acts on it.
In a trial where people added 5 cups of legumes a week and changed nothing else, the result matched a substantial daily calorie cut for waistline and blood sugar, and beat it on cholesterol. Adding food, not removing it.
Lentils and Iron
Lentils are a good source, and the iron in them behaves differently from the iron in meat in a way that is usually reported as a disadvantage and is not.
Plant iron is regulated by your body. If you are low, you absorb more of it. If you have plenty, you absorb less. Your gut cannot do that with the iron in meat, which slips through whether you need it or not.
So the answer to absorbing more of it is not more lentils. It is what you put next to them.
- Vitamin C in the same meal. An orange alongside can raise absorption several times over. A squeeze of lemon into the pot at the end does the same job and is easier to remember.
- Tomatoes and peppers count. Which is convenient, because they were going in anyway.
- Tea and coffee at the meal work against you. Move them half an hour either side.
Venny: One thing I want to say plainly, because food writing gets it wrong and the error is not harmless.
If you are a man, or a woman past the menopause, and a blood test shows you are iron deficient, the cause is usually not your diet. It is usually blood loss from somewhere, and the list of causes includes colorectal cancer.
Being told to eat more lentils and pair them with vitamin C is not merely unhelpful in that situation. It can delay a diagnosis. Take a low iron result to your doctor and let them find out why, rather than treating it in the kitchen.
Venny is a medical doctor and a dietitian; Andy is a psychologist. This is general information rather than medical advice.
If Lentils Upset Your Stomach
Lentils are the gentlest legume, which is why we send people here first rather than to chickpeas or kidney beans.
If beans have historically been a problem, start with 2 tablespoons a day rather than a bowlful, and build up over 2 or 3 weeks. The phrase we use is low and slow to grow. The bacteria that digest these fibres have to multiply first, and they cannot do that overnight.
Red split lentils are the easiest of the easy, because there is no skin on them. Skimming the foam off the top while they simmer helps too.
The full explanation, and the research behind the ramp, is in our guide to bean patties.
Lentil Troubleshooting
They will not soften
Nine times out of ten there is acid or salt in the pot. Tomatoes, lemon, vinegar or a stock cube added at the start will hold the skins firm indefinitely.
The tenth time it is age. Lentils do not spoil, but a bag that has been open for two years takes much longer and sometimes never gets there.
They turned to mush
You bought split ones, or you cooked whole ones too long. Red split lentils cannot hold their shape, and no technique will make them.
If you want lentils you can still see, buy green or brown and start testing at 20 minutes.
The pot foamed over
Normal. Cook them uncovered and skim it off with a spoon for the first few minutes.
They taste of nothing
Lentils are a carrier rather than a flavour, and they need more seasoning than feels reasonable. Most people use about half what the pot wants.
Finish with acid. A squeeze of lemon at the end does more for a pot of lentils than another pinch of salt will.
There was a stone in it
It happens, and it is the one genuine argument for tipping them out and looking before they go in the pan. Ten seconds.
What to Make With Them
Roughly in the order we actually cook them.
- Easy Red Lentil Soup: the one we make most. It thickens itself and nothing needs adding.
- Vegan Lentil Bread: the most read recipe on this site. Soaked and raw, never boiled.
- Quick Red Lentil Cream Soup: fifteen minutes, and the allspice is the part nobody expects.
- Lentil Bread Rolls: the same idea as the loaf, and quicker because rolls bake faster.
- Eastern Red Lentil Stew: thick enough to stand a spoon in, finished with lemon.
- Lentil Meatballs in Tomato Sauce: brown lentils, because these have to hold together.
- Sweet Potato Red Lentil Soup: closer to a dal, and fenugreek is the spice worth buying for it.
- Creamy Coconut Lentil Curry: the richest thing we make with them.
- Lentil Stuffed Peppers: whole lentils, where you want to see them.
- Red Lentil Peanut Butter Casserole: an odd-sounding combination that works.
- Bean and Lentil Soup: both in one pot, and no oil anywhere near it.
Where to Start With Lentils
Buy a bag of red split lentils this week. They cost very little and they keep for a year.
Make the red lentil soup on a weeknight when you have not planned anything, and notice that you did not have to decide anything yesterday to be able to.
Then have it again at lunch the following day, and pay attention to what four in the afternoon feels like.
And, always, seek health consciously.
