Another 5:2 Diet Fast Day – Another Soup Recipe

Celeriac and Sweet Potato Soup – a 5:2 Diet recipe:

You know, I keep promising I won’t make more 5:2 diet recipe soups.  And then, I try to work out what I want to eat on my 5:2 diet fast days – and I keep coming back to soup.  Luckily there are an infinite number of variations on the theme.  This time, I was simply using up vegetables that were lurking in the fridge.  A sweet potato and a piece of celeriac that had been marked down to 30p!

Sweet potato and celeriac soup

It’s a very simple soup – and I was suprised at how tasty and rich it was.  The combination of sweet potato and celeriac makes a naturally thick and creamy soup without the addition of any milk or cream.  It’s lovely just as it is, or with a spoon of creme fraiche.  But for a change, and because I had a slice of pancetta left over in the fridge, I garnished the finished dish with a bit of crumbled crispy pancetta.  You could use bacon instead.  Or, if you want to keep the dish vegggie, then a garnish of some crisp croutons or a little caramelised onion would be perfect.

Sweet Potato and Celeriac Soup with Pancetta

Serves 2
Prep time 5 minutes
Cook time 25 minutes
Total time 30 minutes
Dietary Vegan, Vegetarian
Meal type Soup
Misc Freezable, Pre-preparable, Serve Hot


  • 100g Sweet Potato (peeled and cubed)
  • 200g Celeriac (peeled and cubed)
  • 600ml Vegetable stock (I used Knorr touch of taste)
  • 1 thin slice Pancetta (grilled or dry fried till crispy)
  • Salt and pepper to taste


Step 1 Boil the cubes of celeriac and sweet potato in lightly salted water till tender
Step 2 Drain and mash roughly
Step 3 Stir through the vegetable stock (nb. use the water from boiling the vegetables for extra flavour)
Step 4 Zap with a hand blender and simmer gently for 5 minutes. Taste and add salt and pepper as required
Step 5 Serve garnished with the pancetta crisps - or with croutons for a vegetarian option

This soup without garnish is around 85 calories per serving.  Obviously the final calorie count will depend on what you use but half a slice of dry fried pancetta will be around 20 calories.  And, it adds just a little protein to the dish, helping to make it keep you feeling full for longer.

Sweet Potato and Celeriac Soup with Pancetta

So, a perfect 5:2 diet fast day lunch.


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  1. says

    This looks lovely, I have never made my own soup before but looks so simple! I made sweet potato wedges with dinner tonight, I love sweet potato!xx

  2. says

    Celeriac and sweet potato are great detoxers, helping to shunt waste out of the body. This soup sounds yummy, especially with more snow and ice coming in to NYC.

  3. says

    I have always been a bit sceptical about cooking celeriac. I really cannot tolerate the flavour of celery. Is it similar in flavour? But your soup looks really tempting.

    • says

      to be honest, for me yes it does have a mild celery taste. It isn’t as strong though. I’ve made sweet potato and carrot soup in the past though, you might want to try that…

  4. says

    Another FABULOUS 5:2 diet recipe Fiona and I LOVE the addition of pancetta too! Clever and tasty addition to perk this soup up!

  5. Pamela Morse says

    I would not have thought of this combo..I do regular potato with celery root, but this sounds like a richer version…mmmm.

  6. says

    Always like your soups Fiona and this one is no exception. I do like celeriac, but I’m pretty sure I haven’t had it with sweet potato before.

  7. says

    Loving the cheeky pancetta addition!. Celeriac is such a wonder veg (as is sweet potato). Packed full of the good stuff but very few cals. Great for 5:2 I’d imagine.

  8. says

    Another excellent soup that I want to eat immediately. Of course you notice I am totally ignoring your topping and pretending it isn’t there LOL!


    Oooh another soup I have got to try! Have never tried celeriac before – I actually ummed and ahhed over it the other day because someone suggested celeriac mash. Will have to definitely try this though as I love sweet potato. xoxo

    • says

      celeriac mash only really works if you like the taste of celery…it DOES have a mild celery flavour. I rather like it with the right ‘partner’ – white fish or chicken for instance…