In this article
- Do lentils have fiber in a normal portion?
- Red, brown or green: does the color change the fiber?
- Lentils next to grains and other protein foods
- What the fiber in lentils does for you
- Iron, folate and the rest of a cup
- A pot of pasta sauce, half lentils
- Easy ways to work lentils into your week
- How lentils fit your daily fiber target
- The one caveat: a sensitive gut
- Lentils and fiber: your questions answered
- Sources
Lentils tend to get filed under protein, the thing vegetarians eat instead of meat. Do lentils have fiber, too? They have more than most foods in the store: 15.6 grams in a cup of boiled lentils, according to USDA FoodData Central.
That single cup covers more than half of the 28 gram Daily Value. The protein is real as well, at about 18 grams, but fiber is where lentils quietly outperform nearly everything around them.
Do lentils have fiber in a normal portion?
USDA lists boiled lentils at 7.9 grams of fiber per 100 grams, with 116 calories. Here’s how that plays out at the portions you’re likely to use.
| Lentils (USDA) | Portion | Fiber | % Daily Value | Calories |
|---|---|---|---|---|
| Boiled, no salt | 1/4 cup (about 50 g) | 3.9 g | 14% | 58 |
| Boiled, no salt | 1/2 cup (about 99 g) | 7.8 g | 28% | 115 |
| Boiled, no salt | 1 cup (198 g) | 15.6 g | 56% | 230 |
| Raw, dry | 1 cup (192 g) | 20.5 g | 73% | 676 |
| Red or pink, raw | 100 g | 10.8 g | 39% | 358 |
The FDA treats 20% of the Daily Value or more per serving as a high source. A half cup clears that line with room to spare, and even a quarter cup sprinkled over a salad gets you close to 4 grams.
Cooked lentils are about 70% water by weight in USDA data. That’s why a cup of dry lentils shows a bigger fiber number: you’re looking at a much larger amount of food once it absorbs water in the pot.
Red, brown or green: does the color change the fiber?
Red lentils cook down into a soft puree, so it’s easy to assume they carry less fiber than firmer brown or green ones. The numbers say otherwise.
USDA lists raw red lentils at 10.8 grams of fiber per 100 grams and its general raw lentil entry at 10.7 grams. Texture changes in the pot, but the fiber count on paper is essentially the same.
Iron follows a similar pattern. Raw red lentils list 7.4 mg per 100 grams, slightly more than the 6.5 mg in USDA’s general raw lentil entry.
So choose by the dish. Use whichever lentil suits a soup, a salad or a curry, and expect a similar fiber payoff from each.
Lentils next to grains and other protein foods
Lentils usually take the place of either a grain or a meat on your plate. The Dietary Guidelines for Americans list makes the comparison easy.
| Food (DGA serving) | Fiber | Calories |
|---|---|---|
| Lentils, cooked, 1/2 cup | 7.8 g | 115 |
| Bulgur, cooked, 1/2 cup | 4.1 g | 76 |
| Spelt, cooked, 1/2 cup | 3.8 g | 123 |
| Teff, cooked, 1/2 cup | 3.6 g | 128 |
| Barley, cooked, 1/2 cup | 3.0 g | 97 |
| Almonds, 1 oz | 3.5 g | 164 |
| Sunflower seeds, 1 oz | 3.1 g | 165 |
A half cup of lentils carries nearly twice the fiber of the same amount of bulgur, and more than two and a half times the fiber of barley. It also beats an ounce of almonds while costing about 50 fewer calories.
Scale up to a full cup and the gap widens. Lentils’ 15.6 grams beat the top vegetable on the Dietary Guidelines list, a cup of cooked artichoke at 9.6 grams, and the top fruit, a cup of sapote at 9.5 grams.
Meat, poultry, fish and eggs add none at all. Mayo Clinic defines dietary fiber as the parts of plant foods your body can’t digest or absorb, so every swap from meat to lentils is a straight fiber gain.
Grains still earn a spot. Mixing lentils with bulgur or barley gives you the chew of a grain with a fiber total that neither food reaches alone.
What the fiber in lentils does for you
Mayo Clinic lists beans among the foods that supply both main types of fiber. Monash University’s research dietitians break down how each one works in legumes such as lentils:
- Soluble fiber helps maintain healthy blood glucose and cholesterol levels
- Insoluble fiber adds bulk to stools and helps prevent constipation
- Prebiotic fiber feeds gut bacteria, which ferment it into short chain fatty acids
Monash also notes that legumes have a low glycemic index, a measure of how quickly a food raises blood sugar, and are low in saturated fat. USDA’s boiled lentils carry just 0.4 grams of total fat per 100 grams.
Monash adds that fiber in legumes helps you feel full after eating. Pair that with lentils’ 18 grams of protein per cup, and a lentil based meal tends to hold you for a while.
If you’re building up fiber to keep your digestion steady, our gut health guides walk you through the process at a pace that feels comfortable.
Iron, folate and the rest of a cup
Lentils also stand out for folate and iron. USDA lists these amounts per 198 gram cup of boiled lentils:
- Folate: 358 µg, 90% DV
- Iron: 6.6 mg, 37% DV
- Copper: 0.5 mg, 55% DV
- Manganese: 1.0 mg, 43% DV
- Phosphorus: 356 mg, 29% DV
- Thiamin: 0.33 mg, 28% DV
- Zinc: 2.5 mg, 23% DV
- Potassium: 731 mg, 16% DV
The National Institutes of Health lists half a cup of boiled lentils at 3 mg of iron, the same as half a cup of boiled spinach or firm tofu. Chickpeas and canned kidney beans deliver 2 mg for the same half cup.
The NIH sets the iron RDA at 18 mg a day for women 19 to 50 and 8 mg for men. One cup of lentils supplies more than a third of the women’s amount and over 80% of the men’s.
Getting more from lentil iron
Plant foods contain nonheme iron, which the body absorbs less readily than the heme iron in meat, according to the NIH. That’s why it estimates iron needs are 1.8 times higher for people who follow vegetarian diets.
Vitamin C helps. The NIH notes that ascorbic acid enhances the absorption of nonheme iron, so adding a vitamin C rich ingredient to a lentil dish is a simple way to get more from the iron already in the bowl.
A pot of pasta sauce, half lentils
Monash University suggests a practical swap: replace half the meat in a bolognese or casserole with canned lentils. Picture a sauce that normally uses a full pound of ground beef for four servings.
Swap half the beef for about 1.5 cups of cooked lentils and the pot gains roughly 23 grams of fiber, close to 6 grams per serving. The all beef version started at zero.
Serve that sauce over a cup of cooked whole wheat spaghetti, which USDA lists at about 5.9 grams of fiber, and each plate passes 11 grams without anyone needing to change a favorite recipe.
Looking for more lentil dishes like soups, curries and weeknight sauces? Our recipe eBooks are stocked with high-fiber meals built around them.
Easy ways to work lentils into your week
You don’t need a new cookbook to start. Each of these uses a portion from the table above:
- Stir 1/2 cup of cooked lentils into a pot of vegetable soup for 7.8 grams of fiber per bowl
- Toss 1/4 cup over a green salad for about 3.9 grams
- Fold 1/2 cup of cooked lentils into 1/2 cup of cooked bulgur for a grain bowl base with about 11.9 grams
- Use red lentils to thicken a curry or stew in place of cream
- Keep a can of lentils on hand, rinsed, for a quick protein and fiber boost
Three half cup servings across a week add about 23 grams of fiber, close to a full day’s target spread over seven days.
How lentils fit your daily fiber target
Mayo Clinic suggests about 25 grams of fiber a day for women 50 and younger and 38 grams for men, with targets of 21 and 30 grams after 50. A single cup of lentils covers 62% of the 25 gram goal and 41% of the 38 gram goal.
Mayo also recommends whole foods over fiber supplements and suggests raising fiber gradually over a few weeks while drinking plenty of water. A food this concentrated is easy to overdo on day one.
A practical rhythm is a half cup at lunch and another at dinner. Those two portions give you 15.6 grams, more than half of the 25 gram target, while leaving plenty of room for fruit, vegetables and whole grains.
Not sure which of those targets applies to you? Our fiber calculator gives you a personal number in a few seconds.
The one caveat: a sensitive gut
Lentils’ biggest strength is also their main limit. Monash notes that legumes are naturally high in oligosaccharides, carbohydrates called GOS and fructans that can trigger gas and bloating in people with irritable bowel syndrome.
Canned lentils, or lentils boiled and drained, tend to be lower in these carbohydrates because some leach into the liquid and are rinsed away. Monash says legumes don’t need to be strictly avoided, so if a full cup leaves you uncomfortable, start with a rinsed quarter cup and build from there.
Lentils and fiber: your questions answered
How much fiber is in a cup of lentils?
About 15.6 grams in one cup (198 grams) of boiled lentils, according to USDA. That’s 56% of the 28 gram Daily Value for 230 calories.
Are lentils high in fiber?
Yes. A half cup of cooked lentils has 7.8 grams of fiber, about 28% of the Daily Value, well above the FDA’s 20% threshold for a high source.
Do red lentils have less fiber than green or brown?
No. USDA lists raw red lentils at 10.8 grams of fiber per 100 grams and its general raw lentil entry at 10.7 grams, so the difference is negligible.
Do lentils have more fiber than beans?
Lentils hold their own. The Dietary Guidelines list puts a half cup of cooked lentils at 7.8 grams, ahead of black beans at 7.5 grams and chickpeas at 6.3 grams, though navy beans lead at 9.6 grams.
Are lentils good for constipation?
They can help. Lentils supply insoluble fiber, which Monash University notes adds bulk to stools and helps prevent constipation, and Mayo Clinic advises drinking plenty of water as you increase fiber.
Why do lentils cause gas?
Lentils contain oligosaccharides that gut bacteria ferment, which can produce gas. Rinsed canned lentils tend to be lower in these carbohydrates, and starting with small portions gives your gut time to adjust.
How much iron is in lentils?
About 6.6 mg per cup of boiled lentils, or 37% of the Daily Value. Pairing lentils with a vitamin C rich food helps your body absorb more of this plant based iron, according to the NIH.
Sources
- U.S. Department of Agriculture, Agricultural Research Service. “Lentils, mature seeds, cooked, boiled, without salt (172421); lentils, raw (172420); lentils, pink or red, raw (174284); pasta, whole-wheat, cooked (168910).” FoodData Central, SR Legacy. 2019. fdc.nal.usda.gov
- U.S. Department of Agriculture and U.S. Department of Health and Human Services. “Food Sources of Dietary Fiber.” Dietary Guidelines for Americans, 2020 to 2025. dietaryguidelines.gov
- NIH Office of Dietary Supplements. “Iron: Fact Sheet for Health Professionals.” 2025. ods.od.nih.gov
- Collins, L. “Including legumes on a low FODMAP diet.” Monash University FODMAP blog. 2016. www.monashfodmap.com
- Mayo Clinic Staff. “Dietary fiber: Essential for a healthy diet.” Mayo Clinic, 2025. www.mayoclinic.org
- U.S. Food and Drug Administration. “Daily Value on the Nutrition and Supplement Facts Labels.” 2024. www.fda.gov
