It might be summer here in Australia, but I’m already anticipating soup season. To add to my low FODMAP soup collection, today we’re making low FODMAP lentil soup.

You might be thinking that ‘low FODMAP’ and ‘lentil’ shouldn’t be in the same sentence. Think again! Thanks to appropriate serving sizes and canned lentils, this soup is suitable for those on the low FODMAP diet.

Low FODMAP lentil soup

Name: Low FODMAP lentil soup
Prep time: 15 min
Cook time: 20 min
Ingredients: 60 ml (3 tablespoons)* garlic infused ghee or olive oil; 2 large leek greens thoroughly washed and sliced thinly; 1 bunch spring onion greens sliced; 1/2 bunch flat leaf parsley soft stems and leaves (reserve remaining 1/2 for serving); 50 g tomato paste; 300 g carrot small cubes; 1 – 1 1/2 litres ((1000-1250ml) water or low FODMAP vegetarian stock); 1-2 tablespoons* nutritional yeast; 1/2 – 1 tablespoon* gluten free dark miso; 2-3 teaspoons dried sage leaves; 2-3 teaspoons dried oregano; 1 – 1 1/2 teaspoons salt to taste (to taste if you use stock); Fresh pepper to taste; Squeeze of fresh lemon juice; 1 x 400g can brown lentils (drained and rinsed); 1/2 – 1 bunch Tuscan kale or other hardy greens (woody stems removed and chopped relatively finely); Vegetarian or vegan parmesan; Garlic infused oil; Extra lemon juice

This soup is made from a simple base of leek greens, spring onion greens and chopped carrots. Think of this as your low FODMAP mirepoux or soffrito – the base of the soup. From there, we add flat leaf parsley, tomato paste and dried herbs for flavour. Gluten free dark miso paste and nutritional yeast are an (optional) umami hit, and the canned lentils are for protein. I like to finish my lentil soup off with 1/2 – 1 bunch of Tuscan kale for greens, but any greens would work here.

This low FODMAP lentil soup is vegetarian or vegan, grain free and nut free. It takes 30 minutes to make, so it’s a great weeknight dinner. Unlike minestrone, there’s no pasta to go mushy over time, so this soup makes for a great freezer or meal prep option, too.

Tips for your low FODMAP lentil soup

The biggest tip I could give anyone for working with leek greens is to wash between every single leaf. You would be amazed at how much dirt lurks in the inner leaves of a leek. Peel them off and wash them one by one to ensure your soup is not gritty.

There is a section below specifically on the lentils and ensuring you get a low FODMAP serve of lentils.

However, I recommend draining and rinsing your canned lentils well. Canned lentils are lower FODMAP because the FODMAPs leech out into the canning liquid. As a result, you want to wash that right off.

I love using garlic infused ghee for the best of my low FODMAP lentil soup. I find the flavour carries through to the final dish, unlike with garlic infused oil. If you don’t want to use ghee or need a vegan option, however, adding garlic infused oil to the top just before serving does add a garlic hit.

Because lentils contain starches, the soup will thicken as it cools. If you’re using it for a meal prep situation, add some water or stock before reheating.

An aerial close up view of a bowl of low FODMAP lentil soup topped with grated parmesan and served with a slice of buckwheat bread. The soup sits in a white speckled ceramic bowl atop a white marble table.

Notes on the lentils

Because the lentils are really the main FODMAP concern in this soup, they’re worth chatting about. Firstly, I have used canned brown lentils for this soup. At the time of writing, Monash says that they are considered low FODMAP in 46g serves per person. A standard can of lentils in Australia is 400g net weight. However, the total amount of lentils once drained is approximately 240g.

So, 240g of drained lentils needs to serve 5-6 people. Canned lentils are moderate FODMAP at 65g, which means there might be a bit of wiggle room here. Assess your own tolerance to GOS and go from there.

To ensure you get a low FODMAP quantity of lentils, you can:

Make the soup serve 6. Depending on appetites, you might consider adding 100g extra carrot and the other 1/2 of the bunch of kale to bulk things out. I’d also recommend serving with some gluten free bread (my buckwheat bread, perhaps?)
Make the recipe serve 4-5, and use slightly less than 1 can of lentils. If you go this route, you can throw the remaining lentils into the bowl of anyone in the house who has no FODMAP issues. A win win.

An aerial close up view of a bowl of low FODMAP lentil soup topped with finely grated parmesan. The soup sits in a beige speckled ceramic bowl atop a grey steel backdrop.

FODMAP notes

Spring onion greens and leek greens are low FODMAP and a great way to add onion flavour.

Tomato paste is low FODMAP in 2 tablespoon or 28g serves. This soup uses 50g, which is well under the FODMAP threshold when divided by 5-6 serves.

I have tried to keep everything else low or no FODMAP. Make sure you use a low FODMAP stock if you’re using stock. Personally, I like using water here as the soup is already very flavourful.

A close up macro view of a bowl of low FODMAP lentil soup with buckwheat toast dipping into the top right corner. A spoon sits in the top left corner, revealing the bright red broth of the soup.

Optional add ins

The sky is the limit when it comes to adding in vegetables to this soup. You can substitute kale for another hardy green, add some zucchini, or really throw in any bottom of the fridge you’ve got going. I daresay some finely cubed pumpkin would go down a treat.

You can also another herb that works for you. I’d recommend basil or chives, perhaps a small amount of sage.

Personally, I like to finish my soup with a generous grating of vegetarian parmesan and some garlic infused oil. I have a list of vegetarian parmesan brands in Australia (yes, they exist). I have also recently tried Green Vie vegan parmesan and I think it’s the best I have tried so far.

Because I really enjoy this soup, I am going to work on a curried version as well. Think part low FODMAP daal and part soup.

More low FODMAP vegetarian or vegan soup recipes