IBS and plant-based diet

In IBS, FODMAPS (found in many plant foods) can trigger unpleasant gastro symptoms. These include bloating, gas, diarrhoea, and constipation.

If you have IBS, this can make following a plant-based diet hard.

The biggest issues is that most protein-rich plant foods contain one or more FODMAPS. But armed with knowledge and simple strategies, an IBS friendly plant-based diet is achievable.

WARNING: I recommend that you speak to an experienced Dietitian before removing any core foods from your diet.


FODMAPs are a type of carbohydrate found in a wide range of plant foods. They aren’t absorbed in the small intestine, so they pass through into the colon undigested.

Gut bacteria ferment them, creating gas, which are also called short chain fatty acids (or SFAs).

Put simply, SFAs are awesome. They feed your intestinal cells and improve gut health. But, they are also the cause of the gas and bloating.

While unpleasant, these symptoms aren’t always a sign of intolerance. Nor does it mean you should always avoid foods that cause gas. In fact, the more we avoid them, the worse it can get.

FODMAPs in plant based protein

fODMAPS are Not Equal

Not all FODMAPs trigger everyone.

Kidney beans may make you gassy, but not chickpeas. Or raw onion, but not cooked onion. Or cauliflower, but not broccoli.

Different foods have different FODMAPs, in different amounts. Which means they affect different people differently.

FODMAP Thresholds

People have different FODMAP tolerance thresholds. You might be ok with one cup of lentils, but a cup and a half causes you problems.

A trained dietitian can help you identify trigger FODMAPs, and your tolerance thresholds.

What’s awesome is your FODMAP threshold improves the more you include them in your diet. This only applies to IBS and NOT food allergies or coeliac disease.

The authority on all things FODMAP is Monash University, who state…

“Low FODMAP treatment isn’t about cutting out entire food groups forever – it’s about observing your reaction to foods, and eventually reintroducing them to your diet in a way that suits your body.”


FODMAPs accumulate throughout the day. The more FODMAPs in each meal, the more they are likely to impact IBS symptoms. If you have IBS, a good strategy is to avoid FODMAP stacking.

Try not to include more than one trigger FODMAP per meal…or have only one FODMAP heavy meal per day. You can also dilute FODMAPs in a meal. For example…

You react to broccoli and garlic, but you love a good stir-fry. Try making your stir-fry with broccoli (high FODMAP) and tofu (low FODMAP).

Then choose low FODMAP vegetables such as carrots, bell peppers, and zucchini. Of course, you’ll want rice, which is also low FODMAP. Garlic flavored olive oil or garlic powder can replace high FODMAP fresh garlic.

In this meal, the only high FODMAP food is broccoli!

It’s all about the protein

Many of the most protein-rich plants such as beans, peas, and legumes, are high in FODMAPs. This can make it hard to meet your protein, mineral, and vitamin requirements on a low FODMAP diet. But, a good rule of thumb is to include 3 servings of high-protein plant foods each day. No matter which ones you choose.

Choose the ones that you feel most comfortable with, but include a wide variety.

HOT TIP: A simple way to reduce FODMAP load is to swap the ow protein FODMAPs (such as garlic and onion) for other spices and herbs. Or use flavoured oils, and onion and garlic powders, which are low in FODMAPs.

Low FODMAP plant proteins and grains include:

  • Tofu
  • Tempeh
  • Canned lentils and chickpeas
  • Quinoa
  • Oats
  • Pea, soy, peanut and rice protein powders (in moderation)
  • Peanut butter
  • Sunflower butter
  • Chia seeds
  • Walnuts
  • Macadamia nuts
  • Peanuts
  • Pumpkin seeds
  • Soy milk made from soy protein (not whole beans)
  • Quorn mince (check for egg as not all Quorn products are vegan)
  • Fable mushroom meat
  • Beyond meat
  • Buckwheat
  • Sprouted mung means
  • Hemps seeds
  • Sunflower seeds
  • Flaxseeds
  • Rice
  • Corn
  • Corn and maize flour
  • Polenta
  • Millet
  • Sorghum

High FODMAP plant proteins:

  • Edamame
  • Products made from soy flour (e.g. TVP mince or whole bean soy milk)
  • Lupin flakes and flour
  • Seitan
  • Gluten or wheat-based mock meats
  • Legumes except for lentils and chickpeas
  • Wheat-based bread
  • Basically all other grains

Vegetables vary in their FODMAP content, but as they are less important for meeting nutrient needs, I will skip discussing these here.

Cooking reduces FODMAPs

Good preparation and cooking techniques will minimise FODMAP activity in legumes and vegetables.

  • Soaking legumes for 12-24 hours will make them more digestible as anti-FODMAP enzymes are unleashed. But not all legumes need 24 hours…peas and lentils only need 4-6hrs.
  • Boiling (or pressure cooking) legumes thoroughly will reduce the remaining FODMAPs by up to 70% and won’t destroy the proteins.
  • FODMAPs are water soluble, so the best cooking methods are water based – such as boiling and steaming.
  • Canned legumes (rinsed and drained) are another good option for people with IBS, as they’re also lower in FODMAPs.
  • Cooking with seaweed (especially kombu) also helps to deactivate FODMAPs.

In Summary

Yes, a balanced, plant-based low FODMAP diet is possible! But it takes some planning and dedication.

The more foods you need to restrict, the harder it will be to meet your nutrient requirements. And the more limited your diet is, the harder it will be to stay plant-based.

That said, if you really need to follow a low FODMAP plant-based diet, here are some tips:

  • Don’t fear FODMAPs. They are not toxic or unhealthy…in fact they’re found in the healthiest of foods.
  • A FODMAP-trained dietitian can help identify your trigger FODMAPs and tolerance threshold. Get support!!
  • Avoiding stacking FODMAPS to minimise symptoms.
  • Soaking and thorough cooking FODMAPS can reduce symptoms.

If you’re new to plant-based eating, please check out my top tips for new vegans here.

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