Are Lentils Allowed on a Low FODMAP Diet?

January 11, 2026 •

4 min read

According to Monash University, the source of the low FODMAP diet, specific types and serving sizes of lentils can be included, even during the elimination phase. The key to successfully incorporating lentils is understanding which variety to choose and how to prepare them to reduce their fermentable carbohydrate content.

Quick Summary

Lentils can be safely eaten on a low FODMAP diet in small, carefully measured portions. Preparation is crucial, as the canning and rinsing process significantly reduces FODMAPs. Serving sizes vary by lentil type and preparation method, so portion control and mindful consumption are essential to avoid digestive issues.

Key Points

Canned lentils are a low FODMAP option: Canned, drained, and rinsed lentils have significantly lower FODMAP content due to the water-soluble compounds leaching out into the canning liquid.
Portion size is critical: Safe serving sizes for a low FODMAP diet are small and vary by preparation; for example, 46g of canned lentils versus 23g of cooked dried red or green lentils.
Dried lentils require special preparation: To reduce the FODMAPs in dried lentils, they should be soaked overnight and then cooked in fresh, separate water, which is then discarded.
Monitor your individual tolerance: Everyone's tolerance to FODMAPs differs, so it's important to start with a very small portion and gradually test your personal reaction before increasing the amount.
Mindful combining is key: Avoid combining lentils with other foods high in the same type of FODMAP (oligosaccharides) to prevent 'stacking' that could lead to symptoms.
Nutritionally beneficial in small serves: Even in small portions, lentils provide valuable nutrients like protein, fiber, iron, and folate, making them a worthy addition to a low FODMAP diet.

Understanding FODMAPs in Legumes

FODMAPs are short-chain carbohydrates that can be poorly absorbed by the small intestine and fermented by gut bacteria in the colon, causing gas, bloating, and pain for those with Irritable Bowel Syndrome (IBS). Lentils and other legumes contain galacto-oligosaccharides (GOS) and fructans, types of FODMAPs that are water-soluble. This water-soluble nature is the key to reducing their FODMAP content through specific cooking methods.

How Preparation Method Affects FODMAP Content

The way lentils are processed and cooked plays a significant role in their FODMAP levels. Because FODMAPs are water-soluble, they leach out into the liquid surrounding the lentils. By discarding this liquid, you can dramatically lower the FODMAPs in your meal.

Canned Lentils: During the canning process, lentils are soaked and cooked in water. A significant portion of the FODMAPs leaches into this liquid. When you purchase canned lentils, draining and thoroughly rinsing them under cold water removes this FODMAP-rich fluid, making the lentils more gut-friendly. This is often the easiest and most reliable low FODMAP option.
Dried Lentils: Cooking dried lentils from scratch results in higher FODMAP levels because the cooking water is often used in the final dish. To reduce FODMAPs, you must discard both the soaking water and the boiling water. Soaking dried lentils overnight before boiling them in fresh water and discarding the liquid is a multi-step process that can lower the FODMAP content.

Low FODMAP Serving Sizes for Lentils

Monash University, the institution that pioneered the low FODMAP diet, has tested specific serving sizes for different types of lentils. It is crucial to use a digital kitchen scale for accuracy when measuring your portions.

Low FODMAP Lentil Serving Recommendations

Canned Lentils (any variety), drained and rinsed: The Monash University app lists a low FODMAP serving as 46g (approximately ½ cup).
Boiled Green Lentils (cooked from dried): A smaller serving of 23g (approximately ¼ cup) is considered low FODMAP.
Boiled Red Lentils (cooked from dried): Also a smaller serving, 23g (approximately ¼ cup), is low FODMAP.
Le Puy Lentils (cooked): Monash tests show a 46g (approximately ¼ cup) serving is low FODMAP.

Comparing Canned vs. Dried Lentils


Feature	Canned Lentils (drained & rinsed)	Dried Lentils (properly prepared)
FODMAP Content	Significantly lower, as FODMAPs leach into canning liquid.	Higher FODMAPs remain unless properly soaked and boiled with water discarded.
Low FODMAP Serving Size	Generous 46g serving, easier to incorporate into meals.	Much smaller 23g serving for red and green varieties, requiring more careful portion control.
Preparation Effort	Minimal: simply drain, rinse, and use.	More involved: requires overnight soaking, rinsing, and cooking in fresh water.
Nutrient Density	Still rich in protein, fiber, and iron even in low FODMAP portions.	High nutrient density, but must be consumed in small amounts on a low FODMAP diet.
Best for	Quick meals, salads, and soups where FODMAP management is key.	Individuals who prefer cooking from scratch and can meticulously manage small portions.

Incorporating Lentils into Your Low FODMAP Meal Plan

When adding lentils back into your diet, start with a small, tested portion of canned, drained, and rinsed lentils. Wait 24-48 hours to monitor your body's response before increasing the amount. This phased approach helps you determine your personal tolerance level. It's also important to practice 'FODMAP stacking awareness' by not combining lentils with other moderate FODMAP foods in the same meal, which could overload your digestive system.

Recipe Idea: Try a simple lentil and vegetable soup using canned lentils, low FODMAP stock, carrots, and spinach. Start with a small portion of lentils, such as 2 tablespoons, and increase slowly if tolerated.
Meal Prep: Add small amounts of canned, rinsed lentils to salads or grain bowls with quinoa (a very low FODMAP grain).

Alternative Plant-Based Proteins

If your tolerance for lentils is very low, or you need larger protein portions, several other options are available. Firm tofu is a very low FODMAP source of complete protein, and quinoa is an excellent grain option that is well-tolerated in generous serving sizes. These alternatives can help diversify your plant-based protein intake without risking digestive distress.

Conclusion

So, are lentils allowed on a low FODMAP diet? The answer is a qualified yes, provided you manage them correctly. The key is understanding that preparation matters significantly and canned, drained, and rinsed lentils are the safest and easiest option. By adhering to the recommended small serving sizes, you can enjoy the nutritional benefits of lentils—like fiber, protein, and iron—without triggering uncomfortable IBS symptoms. Always monitor your personal tolerance and use a methodical approach when reintroducing any FODMAP-containing food. With the right techniques and portion control, lentils can be a delicious and healthy component of your gut-friendly diet.

Frequently Asked Questions

Canned lentils are lower in FODMAPs because the canning process involves soaking and cooking, which causes water-soluble FODMAPs to leach into the liquid. When you drain and rinse the canned lentils, you discard this FODMAP-rich fluid.

According to Monash University, a safe low FODMAP serving size for canned, drained, and rinsed lentils is 46g, or approximately ½ cup.

Yes, but in a very small portion. The low FODMAP serving for dried, boiled red lentils is 23g (about ¼ cup), and the cooking water must be discarded.

For dried lentils, the best method is to soak them overnight, then discard the soaking water. Next, boil them in fresh water, and finally, discard the boiling water before using the cooked lentils in your meal.

During the reintroduction phase, start with a small, tested low FODMAP portion of canned, rinsed lentils (e.g., 2 tablespoons). Wait a few days to monitor symptoms before gradually increasing the amount. A kitchen scale is helpful for precise measurement.

Excellent low FODMAP alternatives for plant-based protein include firm tofu (very low FODMAP) and quinoa (very low FODMAP). You can also use other legumes in their tested low FODMAP serving sizes, like canned, rinsed chickpeas.

The fructans and GOS in lentils can be poorly digested in some individuals. They travel to the large intestine where gut bacteria ferment them, a process that can cause symptoms like bloating, gas, and abdominal pain in those with IBS.