Are Lentils Low FODMAP? Canned vs Dried and Safe Serving Sizes

Lentils are generally high FODMAP due to their GOS (galacto-oligosaccharide) content, but canned lentils that have been drained and rinsed are significantly lower in FODMAPs and may be tolerated in small servings. According to Monash University, a half-cup (46g) of canned, drained lentils is rated low FODMAP, while larger portions or dried cooked lentils quickly move into the moderate to high range. For people with IBS, understanding the difference between canned and dried lentils — and controlling portions carefully — is the key to potentially keeping lentils in your diet.

Lentils are a nutritional powerhouse, packed with plant-based protein, fiber, iron, and folate. Eliminating them entirely is nutritionally costly, so finding a way to include them safely is well worth the effort.

Why Are Lentils High in FODMAPs?

Lentils contain GOS, which stands for galacto-oligosaccharides. GOS is a type of oligosaccharide — a short chain of sugar molecules — that the human small intestine cannot break down because we lack the enzyme alpha-galactosidase. When GOS passes undigested into the large intestine, resident bacteria ferment it rapidly, producing hydrogen, methane, and carbon dioxide gas. For people with IBS, this fermentation causes bloating, distension, cramping, and altered bowel habits.

GOS is water-soluble, which is a critical property. When lentils sit in liquid during the canning process, a significant portion of the GOS dissolves into the surrounding water. Draining and rinsing the canned lentils removes that GOS-laden liquid, leaving the lentils with a meaningfully lower FODMAP load.

FODMAP Breakdown: Lentil Types and Preparations

Lentil Type	Preparation	Serving Size	FODMAP Level	Primary FODMAP
Green lentils	Dried, cooked	1/2 cup (100g)	High	GOS
Green lentils	Canned, drained & rinsed	1/2 cup (46g)	Low	GOS (reduced)
Brown lentils	Dried, cooked	1/2 cup (100g)	High	GOS
Brown lentils	Canned, drained & rinsed	1/2 cup (46g)	Low	GOS (reduced)
Red lentils	Dried, cooked	1/2 cup (100g)	High	GOS
Red lentils	Boiled, drained	1/4 cup (23g)	Low	GOS
Puy (French) lentils	Dried, cooked	1/2 cup (100g)	High	GOS
Lentil chips/crisps	Varies	Check label	Moderate–High	GOS

The pattern is consistent across all lentil varieties: dried and home-cooked lentils are high FODMAP in typical serving sizes, while canned and thoroughly rinsed lentils are lower.

Red Lentils vs Green Lentils vs Brown Lentils

People often wonder whether one lentil variety is safer than another. The short answer is that the GOS content is broadly similar across varieties, but there are some practical differences worth noting.

Red lentils cook quickly and break down into a soft, almost puree-like consistency. This makes them popular for dhal and soups. Because they disintegrate, they mix thoroughly with the cooking liquid, which means the GOS distributes evenly through the dish. If you are making a red lentil soup, using a smaller total amount of lentils and keeping your bowl to a modest portion is the safest approach.

Green and brown lentils hold their shape better during cooking and work well in salads, stews, and side dishes. Their firmer texture makes it easier to measure a controlled portion. These are the varieties most commonly available in canned form.

Puy (French green) lentils are prized for their firm texture and peppery flavor. They are nutritionally similar to other lentils and have a comparable GOS profile. They are less commonly found canned.

Canned vs Dried: Why Canned Wins for IBS

The canning process is your best friend when it comes to reducing the FODMAP content of lentils. Here is why:

1. Extended soaking in liquid: Commercial canning involves cooking lentils in liquid for an extended period at high temperatures, which draws GOS into the surrounding water
2. Draining removes the GOS: When you open the can and drain the liquid, you are discarding a significant portion of the dissolved GOS
3. Rinsing further reduces FODMAPs: A thorough rinse under running water removes additional surface GOS

If canned lentils are not available, you can partially replicate this process at home by soaking dried lentils for 12 to 24 hours, discarding the soaking water, and cooking in fresh water. Research suggests this reduces GOS by roughly 20 to 40 percent — helpful, but not as effective as commercial canning.

How to Cook With Lentils on a Low-FODMAP Diet

Lentil salad: Drain and rinse a can of green lentils. Toss a small portion (about half a cup per person) with diced cucumber, cherry tomatoes, bell pepper, fresh parsley, lemon juice, olive oil, salt, and pepper. This makes a satisfying protein-rich lunch.

Small addition to soups: Rather than making a lentil-based soup, add two or three tablespoons of canned, rinsed lentils to a vegetable soup for extra protein and texture without overloading on GOS. Use garlic-infused oil and avoid onion.

Lentil bolognese: Use a small portion of canned lentils mixed with low-FODMAP tomato sauce and ground meat to create a hearty pasta sauce. The lentils add body and nutrition without dominating the dish.

Dhal in small portions: If you love dhal, make it with a moderate amount of red lentils and serve yourself a smaller bowl. Use garlic-infused oil and asafoetida (a spice used in Indian cooking that mimics garlic and onion flavor without FODMAPs).

Does Cooking Method Affect FODMAP Content?

Cooking lentils in water and then draining them reduces GOS content somewhat, similar to the canning process but less dramatically. Slow cooking lentils in a stew or soup where the liquid is consumed means you are eating all of the GOS that leached into the broth. Pressure cooking may break down some GOS, but current research is limited on the exact reduction.

The most reliable strategy remains using canned lentils that have been drained and rinsed, or soaking dried lentils extensively before cooking and discarding the soaking water.

Lentils During the Reintroduction Phase

GOS is one of the FODMAP groups you will test during the reintroduction phase. The standard approach is to start with a small amount of lentils (about two tablespoons) and increase over three test days while monitoring symptoms. Many people discover they have a moderate tolerance for GOS — perhaps a quarter cup of lentils is fine, but half a cup triggers symptoms.

This personalized threshold information is valuable because it tells you exactly how much you can include in your diet going forward. Using an app like FODMAPSnap to track your portions and symptoms during reintroduction helps you identify your personal limits with precision.

FODMAP Stacking With Lentils

If you eat lentils alongside other GOS-containing foods — such as chickpeas, beans, or cashews — in the same meal, the cumulative GOS load adds up. Even if each individual serving is small, the combined effect can exceed your threshold. Be particularly careful with meals that combine multiple legumes.

Key Takeaways

• Dried, cooked lentils are high FODMAP due to GOS content
• Canned, drained, and rinsed lentils are lower in FODMAPs — a half-cup (46g) is rated low FODMAP by Monash
• All lentil varieties (red, green, brown, Puy) have similar GOS levels
• Soaking dried lentils for 12 to 24 hours and discarding the water reduces GOS by 20 to 40 percent
• Start with small portions and increase gradually based on your tolerance
• Watch for FODMAP stacking when combining lentils with other GOS-rich foods
• Canned lentils are the most practical and reliable low-FODMAP option

Related Reading

• Are Chickpeas Low FODMAP? — Another legume with similar GOS concerns
• Are Beans Low FODMAP? — How beans compare and which are best tolerated
• Are Peas Low FODMAP? — A legume with different FODMAP considerations
• FODMAP Food Guide: What You Can and Can’t Eat

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This article is for informational purposes only and does not constitute medical advice. The low-FODMAP diet should ideally be undertaken with guidance from a registered dietitian experienced in digestive health. Always consult your healthcare provider before making significant dietary changes.