Which legumes are FODMAP friendly? A guide to gut-friendly eating

Research from Monash University shows that while many dried legumes are high in FODMAPs, some varieties and preparation methods make them surprisingly FODMAP friendly. This makes it crucial to know which legumes are FODMAP friendly when managing sensitive digestive systems, like those with Irritable Bowel Syndrome (IBS).

Quick Summary

This article outlines which specific legumes are suitable for a low-FODMAP diet, detailing how canning and rinsing lower FODMAP content. It covers Monash-tested safe serving sizes and beneficial alternatives, helping individuals maintain digestive comfort while enjoying nutritious plant-based protein.

Key Points

• Canning Reduces FODMAPs: Canned and rinsed legumes have significantly lower FODMAP levels than dried versions because water-soluble FODMAPs leach into the canning liquid.

• Portion Control is Key: Even low-FODMAP legumes must be consumed in small, Monash-tested serving sizes to prevent the stacking of FODMAPs.

• Green Beans and Edamame are Safe: Green beans and shelled edamame are naturally low in FODMAPs and can be enjoyed in larger servings.

• Beware of Dried and Sauced Beans: Most dried legumes and those prepared in high-FODMAP sauces (like baked beans) should be avoided during the elimination phase.

• Reintroduce Gradually: Over time, you can test your personal tolerance to higher-FODMAP legumes by starting with small amounts and monitoring symptoms.

• Legumes Support Gut Health: Including legumes, even in small amounts, provides prebiotic fiber that feeds beneficial gut bacteria and promotes microbiome diversity.

What are FODMAPs in legumes?

FODMAP is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are short-chain carbohydrates that can be poorly absorbed in the small intestine. Legumes, in particular, are rich in galacto-oligosaccharides (GOS) and fructans, which are the 'O' in FODMAP. When these carbohydrates reach the large intestine, gut bacteria ferment them, producing gas and causing symptoms like bloating, pain, and gas in sensitive individuals. This is why many people with IBS struggle to digest legumes, but proper selection and preparation can make them much more tolerable.

The crucial difference: Canned versus dried

For many legumes, the FODMAP content changes dramatically depending on how they are prepared. The key difference lies in whether they are canned or dried. FODMAPs are water-soluble, meaning they dissolve in water during soaking and cooking. This is why canned legumes often have a lower FODMAP content than their dried counterparts. The commercial canning process, where legumes are soaked and stored in brine, allows a significant amount of the FODMAPs to leach out into the liquid. By draining and thoroughly rinsing canned legumes before use, you can remove a substantial portion of these symptom-triggering compounds. For dried legumes, a thorough soaking and cooking process is essential, and even then, safe serving sizes are typically much smaller.

Safe FODMAP friendly legumes and their serving sizes

For those following a low-FODMAP diet, a variety of legumes can be enjoyed in specific, tested portions. It is always best to check the official Monash University FODMAP Diet App for the most accurate and up-to-date serving sizes.

• Canned Lentils: A low-FODMAP portion of canned, drained, and rinsed lentils is approximately ¼ cup (46g).
• Canned Chickpeas: Often called garbanzo beans, canned, drained, and rinsed chickpeas are low-FODMAP in a ¼ cup (42g) portion. You can roast these for a crunchy snack.
• Edamame: Shelled, frozen edamame is a great low-FODMAP option at a serving size of ½ cup (95g).
• Green Beans: These are a reliably low-FODMAP vegetable and legume. A 15-bean serving (75g) is considered safe.
• Firm Tofu: While not a bean, firm tofu is a legume-based product and is low in FODMAPs because the pressing process removes most of the oligosaccharides. Up to 1 cup (170g) is typically well-tolerated.
• Moong Dal: A low-FODMAP option from Indian cuisine, moong dal can be enjoyed in moderation.
• Canned Butter Beans: Canned and drained butter beans are low FODMAP at a portion size of 2 tablespoons (35g).
• Canned Black Beans: Canned and drained black beans can be included in small servings of about 2 tablespoons (40g).
• Sprouted Mung Beans: A ⅔ cup (95g) serving of sprouted mung beans is considered low FODMAP.

Preparing legumes for a low FODMAP diet

To ensure your legumes are as gut-friendly as possible, follow these preparation steps:

1. Drain and Rinse Canned Legumes: This is the most crucial step for canned varieties. The brine contains the leached-out FODMAPs, so discarding it and rinsing the legumes thoroughly is vital.
2. Soak Dried Legumes: If you choose to cook dried legumes, soak them overnight in water. This helps to draw some of the FODMAPs out. Always discard the soaking water before cooking.
3. Use Small Portions: Even low-FODMAP varieties must be eaten in measured portions. "FODMAP stacking," where multiple low-FODMAP foods containing the same type of FODMAP are consumed in one meal, can trigger symptoms.
4. Experiment During Reintroduction: Once you have completed the elimination phase of the low-FODMAP diet, you can test your tolerance to different legumes. Start with small servings and monitor your symptoms.

High FODMAP legumes to limit or avoid

Some legumes remain high in FODMAPs even with proper preparation and should be avoided or strictly limited during the elimination phase of the diet. These include:

• Dried Lentils (most varieties when freshly cooked from dried)
• Dried Chickpeas
• Baked Beans (canned varieties are high FODMAP due to navy beans and high-FODMAP sauces)
• Split Peas
• Soybeans (mature, whole beans)
• Fava Beans

Low FODMAP legumes at a glance

Legume Type	FODMAP Status (Correct Prep)	Preparation Method	Safe Portion Size (approximate)
Canned Lentils	Low	Drain and rinse well	¼ cup (46g)
Canned Chickpeas	Low	Drain and rinse well	¼ cup (42g)
Frozen Edamame	Low	Cook from frozen	½ cup (95g)
Green Beans	Low	Fresh or cooked	1 cup (75g)
Firm Tofu	Low	Pressed	1 cup (170g)
Dried Lentils	High	N/A (unless small portion)	Check Monash app
Dried Chickpeas	High	N/A (unless small portion)	Check Monash app
Baked Beans	High	N/A	Very small amount (2 tsp)

The benefits of including legumes for gut health

Despite their high FODMAP content in some forms, legumes are a valuable addition to a healthy diet, even in small, controlled portions. They are a powerhouse of nutrition, providing fiber, protein, and essential micronutrients. The prebiotic fibers in legumes feed the beneficial bacteria in your gut, which helps to foster a diverse and healthy gut microbiome. This bacterial fermentation, which can cause symptoms in some, is actually a healthy process that produces beneficial compounds like short-chain fatty acids. Including low-FODMAP legumes in your diet, as tolerated, helps increase fiber intake and promotes overall gut health. A gradual increase in intake can also help your gut adapt and improve tolerance over time.

Conclusion

Legumes do not have to be off-limits for those on a low-FODMAP diet. By understanding which legumes are FODMAP friendly and implementing proper preparation methods, you can successfully incorporate these nutritious foods without triggering digestive symptoms. The key is in selecting canned and well-rinsed varieties like chickpeas and lentils, opting for naturally low-FODMAP choices like green beans and edamame, and always paying close attention to portion sizes. With these strategies, you can continue to reap the significant health benefits of legumes while keeping your digestive system happy.

To learn more about the science behind FODMAPs and find further guidance, visit the Monash University FODMAP Diet website.

Frequently Asked Questions

Are canned chickpeas low FODMAP?

Yes, canned chickpeas are considered low FODMAP when drained and thoroughly rinsed. A safe, low-FODMAP serving is approximately ¼ cup (42g), according to Monash University testing.

Can I eat green beans on a low FODMAP diet?

Yes, green beans are a great low-FODMAP option. A serving of 15 green beans (75g) is considered safe for those with sensitive digestive systems.

What happens if I eat too many low FODMAP legumes?

Consuming too many low-FODMAP legumes at once can lead to 'FODMAP stacking,' where even small amounts from different foods accumulate to a high-FODMAP load. This can trigger digestive symptoms.

Is firm tofu low FODMAP?

Yes, firm tofu is low-FODMAP. The pressing process used to create firm tofu removes most of the oligosaccharides. A serving of up to 1 cup (170g) is generally well-tolerated.

Are baked beans low FODMAP?

Traditional baked beans are typically high in FODMAPs due to the high-FODMAP navy beans and added sauces containing ingredients like onion and garlic. They should be avoided or consumed in very small amounts (2 teaspoons).

Why is there a difference between canned and dried legumes?

The FODMAPs in legumes are water-soluble. During the canning process, these carbohydrates leach out into the liquid. When you drain and rinse the canned legumes, you remove most of the FODMAPs, making them easier to digest.

Can I eat lentils on a low FODMAP diet?

Canned, drained, and rinsed lentils are low-FODMAP in a ¼ cup (46g) portion. Dried lentils that are cooked from scratch are high-FODMAP, so the preparation method is crucial.