5-2 Diet Fast Day Fish

Oven Steamed Cod with Celeriac Champ for a 5-2 Diet Fast Day:

While I was looking for information about how to steam fish for my 5-2 diet Asian fish parcels, I read a little bit about oven steaming.  Now, I am sure you have friends with expensive steam ovens (or perhaps you have one yourself).  A steam oven produces very moist, tender results without having to add any fat.  Perfect for a 5-2 diet fast day, or for that matter for anyone trying to lose weight and follow a low calorie diet programme.

My resolve to try this kind of cooking was increased when I went to the Angler, where I was served Steamed Seabass with herb crushed potato.

low cal oven steamed cod with celeriac champ 5-2 diet

This particular recipe is one that I think is a real winner.  I’ve used celeriac  for the mash instead of potato which is quite high in calories.  (42 calories per 100g for celeriac rather than 78 calories for potato).  It has a mild celery flavour that I really like and when mashed with a little low fat cream cheese it is light and tasty.   It IS a very ugly looking root before it is peeled and cooked, but don’t be put off.  Even if you mix celeriac and potato, you’ll get a lighter and better flavoured mash.  This time I’ve added in chopped parsley and spring onions to make a celeriac champ – mostly because I simply don’t have a great range of fresh herbs at this time of year so I couldn’t recreate the dish I was served at The Angler.

Low Calorie Oven Steamed Cod with Celeriac Champ

Serves 1
Prep time 5 minutes
Cook time 20 minutes
Total time 25 minutes
Allergy Fish, Milk
Meal type Main Dish


  • 4-5 shots 1-cal oil
  • 1 piece Cod Fillet (about 150-180 grams weight)
  • 150g Celeriac Root (Peeled and chopped into 2cm chunks)
  • 2 Spring Onions (Finely chopped)
  • 15g Low calorie soft cheese
  • 1 handful Flat leaf parsley (Finely chopped)
  • 1/2 Lemon


Step 1 Half fill a roasting tin with water and place in the bottom of your oven. Set your oven to 140c
Step 2 Peel the celeriac and cut into 2cm chunks
Step 3 Boil the celeriac in water with a little added salt for around 15 minutes
Step 4 When the oven is preheated, season the fish with salt and pepper and place on a baking tray directly above the roasting pan of water
Step 5 Cook the fish for 10-15 minutes or until you can see protein globules rising (a milky white substance) and the fish is opaque.
Step 6 Meanwhile drain and mash the celeriac. Stir through the spring onions, cream cheese and most of the parsley and season with salt and pepper to taste
Step 7 Serve the fish on a bed of the celeriac champ with a garnish of a little fresh parsley and the lemon

To steam the cod, which was supplied to me by John at Delish Fish, I simply seasoned the fillet with salt and pepper and placed it on a non stick baking tray in the oven.  At the bottom of the oven, a large roasting tin of water created the cooking steam.  It is obvious that this very simple way of preparing fish does depend on excellent quality ultra fresh produce.  And John’s fish always arrives beautifully filleted so that all I have to do is open one of the individual portions to create my very own diet ready-meal!

It took 15 minutes to cook this piece of fish and it was really obvious when it was ready – the flesh of the fish turn opaque and there were little globules of fish proteins on the baking tray.  For me it seemed a lot easier to gauge when the fish was perfectly cooked than using foil or leaf parcels and a steamer on the hob as I did with my steamed thai style cod.  And with results that were every bit as good.  I’m planning on trying again with salmon next.

A little lemon on the side and some fresh and seasonal green vegetables made a perfect, simple and quick supper that was around 250 calories!

Low Calorie Cod with Celeriac champ

 This is the sort of diet meal that means you really don’t feel you are missing anything on a 5-2 diet fast day.  Fish is naturally low in calories and full of protein, so you end up feeling fuller for longer  My personal challenge is simple that I eat out a lot so at times the 5-2 diet does nothing more than maintain my weight.  But, I still feel better the morning after a 5-2 diet fast day – more energised and lively.  And, the weight is slowly dropping, so I must be doing something right on the 5-2 diet.

If you enjoyed this post, please consider leaving a comment or subscribing to the RSS feed to have future articles delivered to your feed reader.


  1. says

    This looks like a sure fire winner of a dish, diet or no diet!
    Glad to hear your weight is dropping, I really should give it a go myself (I’ve been saying that for months now).

  2. olivia kirby says

    This looks delicious. My friend who is doing this diet is allergic to fish and sea food, I reckon that’s a bummer really!
    I really need to do something to shift this weight, I get very ratty with the kids if I don;t eat regularly though!!

    • says

      fish is an easy way to get protein without too many calories. I’m experimenting with some veggie dishes at the moment too though, and they are really low cal. Chicken breast would work quite well as a substitute for fish in this particular dish – you could oven steam it exactly the same way

  3. pat says

    did you know that microwaving fresh fish in a drop of water is just as tasty as steamed, but is quicker and more cost effective than using your oven !

    • says

      I’ve tried, but for me part of the steaming process involves adding herbs and seasoning, sometimes lemon juice or wine. And, obviously the microwave doesn’t help with that. I also find it makes the texture of the fish a bit odd. But, if it works for you fine.

Leave a Reply

Your email address will not be published. Required fields are marked *