5-2 Diet Soup and Update on Fast Days

An Update of Progress on the 5-2 Diet and a Slimmed Down Leek and Potato Soup!

The 5-2 diet is becoming a lifestyle diet for me.  It seems to enable me to VERY SLOWLY lose weight without too much pain.  OK, for 2 days a week I really do have to eat carefully and not drink any alcohol.  But the rest of the time I follow my normal, rather eccentric lifestyle, eating out a lot and (probably) drinking too much wine as well.  So, I’m very happy to report today that I’m now 63.5 kilos.  That’s almost a 10kg loss since I started doing the diet in September last year and given the press trips and holidays, I’m very pleased with myself.  I haven’t given up anything completely and for the most part the food I eat at home is very similar to the food I was eating BEFORE starting on the 5-2 diet.

5-2 diet leek, potato and celeriac soup

There are some changes though.

  • I’m a lot more conscious of portion size.  On 5-2 diet fast days I weigh everything, even celery.  And I think that’s made me more conscious of how to keep the calories low on non fasting days.
  • I am using 1 cal spray a lot on fast days, and where I don’t need to add ‘flavour’, quite regularly in my normal cooking.  I still prefer to cook with olive oil and butter, but for me, I’ve discovered that it is very easy to add more than might be good for my waistline.  So, even on non fast days I generally measure out my fats rather than just happily pouring in a glug of oil.
  • I’m replacing some of the high calorie foods I used to eat with ingredients that are lower in calories.  The recipe below is a really good example.  I’ve been using celeriac as a substitute for potato, and although my Leek, Celeriac and Potato Soup has 100g of potato for texture, most of the ‘thickness’ of the soup comes from celeriac, which has half the calories.  Of course, you could make a thinner soup without the celeriac at all, but during winter I quite like 5-2 diet soups that have body.
  • I’m making more tomato based sauces and fewer creamy ones.
  • I’m using a lot more spices in my recipes.  I do like hot and spicy dishes, and I’ve found that the low fat recipes I’m making at the moment often need more in terms of seasoning with herbs and spices.  Since it is winter there are not so many fresh herbs around (mine seem to last about a week on the windowsill).
  • I’m eating less meat and more white fish and vegetables.  In particular things like a vegetable curry, which I probably wouldn’t even have tried to cook.  I’ve discovered I actually rather like home made vegetarian food.
  • I’m trying a lot of different high fibre foods as a way to bulk out my 5-2 diet recipes and stay feeling full for longer

Anyway, the point of this particular 5-2 diet soup is that by replacing most of the potato with celeriac, you can enjoy a thick, comforting soup for around 70 calories a bowl.  Use potato instead of celeriac and the calorie count goes up to around 100.  While that might not sound so serious, I’d rather save the 30 calories for a treat, especially as I like the slightly aniseedy taste of celeriac.  DO weigh and measure the ingredients you use, both celeriac and potato are quite dense, so you might be suprised that what looks like a very small potato is actually 100g.

Leek, Celeriac and Potato Soup


  • 2 Medium Leeks (Cleaned, trimmed and sliced into 1cm chunks)
  • 200g Celeriac Root (Peeled and chopped into cubes)
  • 100g Potato (Peeled and chopped into cubes)
  • 700ml Stock (Fresh chicken or made with a good quality stock cube or bouillon)
  • 1 teaspoon butter


Step 1 Melt the butter in a heavy based pan
Step 2 Gently soften the leeks in the melted butter for 3-4 minutes
Step 3 Add the potato and celeriac, then pour over the stock and bring to the boil
Step 4 Simmer gently for 15 minutes before blending with a stick blender or in batches in a liquidiser. If you prefer a chunkier soup, just use a slotted spoon to remove 2 spoonfuls of the vegetable mix before blending.
Step 5 Check and add salt and pepper as required (this will depend a lot on the stock you use, so it is worth leaving it till the soup is cooked.
Step 6 Serve with a teaspoon of low fat creme fraiche and/or fresh parsley chopped over

I’ve added a dollop of creme fraiche to the soup in the picture, which will add 15 calories or so.  Served with a parsley garnish the calorie count is as shown below:-

Leek and celeriac soup low calorie


For those of you who haven’t found them yet, there are some great 5-2 diet resources – forums and various facebook groups.  If you are interested, leave a comment below and I’ll post the links.


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  1. says

    Wow, this is amazing Fiona! So proud of you! I recently directed my mom to your site…she has been looking for a diet that doesn’t include artificial shakes and complicated calorie counting every day. This seems like a fabulous, and healthy, alternative!

    • says

      exactly, I think it works because making an effort on 2 days of the week is almost like an education programme for your mind and body. You know you don’t need so much food not to feel hungry and you really start to realise what adds calories. For example, I don’t snack on a diet fast day at all! and so now I don’t snack so much the rest of the time

  2. says

    I have been on a modified 5-2 for about two months now and have dropped approx 8 lbs. As a vegetarian with low blood pressure it is harder to stick to 500 calories, so I try to stay under about 600. Have started to eat a lot more raw vegetables and salads, they are quite good at filling one up on the 2 days!

    • says

      I think in general it’s easier to stay low calorie with vegetarian food, but I’m guessing you are trying to keep some kind of level of nutrients in your meals? But if 600 cals works for you why not? I’d rather lose weight slowly and do something that I can follow in the long term too.

      • pakhipakhi says

        I do not want to skip protein completely on the low cal days, since I have a hard time getting enough other days. Unfortunately beans are quite high in carbs so cannot load up on them. Yes, slow and steady seems to be the ticket.

  3. says

    You are doing so well Fiona. I decided to have a go and started last week, not sure I will keep it up but will try my hardest for a couple of months at least. Cream is the killer for me, has so many calories.
    I’m going to look through all the recipes later!

  4. says

    That soup looks wonderful! I’m on 5:2 as well and liking it a lot. I’ve been dieting since I was eight so to like a diet says a lot! I am a big fan of low cal soups and post them when I can on my website (I’m lazy about posting, but funny about it when I do…)

    I’d love to see the links you made reference to. Please post? :)

  5. Sue Brett says

    Thanks for the recipes, have just started 5:2 diet and would be interested in links to the 5-2 diet resources you mentioned

  6. Coral McCrystal says

    Please include me in newsletter if you run one and I’d be grateful for any links to make 5:2 diet easier. So far I’d only resd a book but I’m kind swamped in books!

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