/ Food & Drink, Health

Are your cornflakes healthy?

Bowl of Cornflakes

You might not think of cornflakes as a sugary cereal, but seven of the 12 we tested contain two or more teaspoons per 100g. Do you think you’re having a healthy start to the day when you tuck in to your cereal?

In our cornflake test, we found Asda Smartprice cornflakes had the most sugar with 9.3g of sugars per 100g. The Co-operative Simply Value had less than a third of this, and the lowest sugar content of all those we tested (at 2.9g per 100g).

However, adding sugar on top of your cereal will of course increase this. If you add a couple of teaspoons to a 30g bowl of Kellogg’s cornflakes, you’ll be consuming as much sugar as in the same serving of Kellogg’s Frosties.

Just a spoonful of cereal

Now the salt content of cornflakes has dropped over the years. But while Kellogg’s has reduced its salt from 1.8g (in 2009) to 1.3g per 100g, its cornflakes are still the saltiest of all on test. The Co-operative Simply Value cornflakes contained the least salt, with 0.5g per 100g.  And the cornflakes that came highest in our taste test were all among the sweetest or saltiest.

Convo commenter Catherine took action following our last breakfast cereal investigation telling us:

‘I was appalled to read this report, it shocked and surprised me. I have discussed this with others too and i was not alone in assuming that all breakfast cereals are kind of healthy – how wrong we were! I might as well as have eaten cake! I’ve been having dizzy spells from blood sugar fluctuations, and no wonder! I have switched to shredded wheat and weetabix and have been feeling much better. Thank you, you have educated me and my family about how irresponsibly these cereals are marketed.’

Realistic portions sizes?

When it comes to portion size, most people would be surprised at the reality of the recommended serving size. Most packs recommend a serving size of 30g with 125ml of semi-skimmed milk, but we have often questioned how realistic this is; 30g is the size of a small box found in variety packs – a very small bowlful. And M&S recommends a perhaps more realistic serving size of 50g.

And when it comes to added vitamins and minerals, all of the cornflakes we tested were fortified, with the exception of Lidl. Most contain a variety of B vitamins and iron, needed to release energy from food and to make red blood cells, which carry oxygen around our bodies. However, some also contain vitamins D or E.

Do you take the nutritional value of your cereal into consideration when making your choice? How do you start a nutritionally sound day?


I haven’t often had a good word to say for Tesco’s but I should like to praise their clear and consistent labelling across their own-brand breakfast cereals. I recently spent a bit of time in the store loking for the cereals with the least salt and sugar content and it was very easy to see the amounts in the Tesco products because they were clearly displayed on the fronts of the boxes. Trying to ascertain Kellogg’s salt and sugar contents was very difficult in comparison because it was buried on the side of the box in tiny dense text in a table surrounded by multi-lingual legend. I certainly agree the “portion size” examples are not helpful – 30g might be right for a small child but most adults probably have 60g or more; M&S’s 50g portion size seems about right for comparison purposes and it woud be good if all manufacturers used the same size [I don’t think we should have more regulations for this – it’s difficult enough to ensure compliance with all the existing codes of practice; consumers could just avoid buying goods that aren’t clearly and sensibly labelled]. Those Tesco cereals that we have tried seem just as tasty [if diffferent] as the bigger brands and could be less harmful.

The big retailers make a point of their ability, through their bulk buying power, to hold down prices and get better value from the manufacturers. It would be good if they could use some of that commercial muscle to get the big cereal brands to display their contents more openly and give the salt and sugar contents greater prominence with bold and simple graphics.


I totally agree about the small portion sizes quoted on cereal packets, John. Comparing the amount of fat, sugar, salt and kJ (or Calories) per 100g is the best option.

Manufacturers of ready meals often use the same tactic of quoting small portion sizes to try to fool customers into believing that their products represent more healthy eating than is the case.


Further to my previous comment . . .

To be fair to Kellogg’s and other manufacturers, clear labelling has now started to appear on the front of cereal packets as the older stock is consumed and it is now becoming easier to compare brands. Unfortunately, the portion sizes are not consistent across brands and not even across different products from the same manufacturer. So I can only give them One Star at the moment. Must try harder.


I am not a cereal fan, but looking at our packet of All-Bran, it states 20g sugars per 100g, and 1g salt (0.4g sodium). Rice Krispies 10g sugars/100g, 1.15g salt (0.45g sodium)/100g. Neither sound healthy. but I’m a hypocrite, because I like salt and sugar I’m afraid. Incidentally, whilst they quote a 30g serving on All-Bran, the Rice Krispies is a single serving pack of – a mean 20g.
My Grandfather used to put salt on his cornflakes every morning, and sugar on his lettuce.
Someone told me there is more nutrition in the carboard box than in the cornflakes – I don’t suppose that’s true.


That’s a powerful combination Malcolm, All-Bran and Rice Krispies. At least it’ll keep you going all day with a snap, crackle and pop.


Malcolm – I have suggested that cereal boxes contain more fibre than the contents on a couple of occasions. Even the worst examples of junk food do contribute to our nutrition. Fibre does not contribute much to human nutrition because most of it is not digested, but it is undoubtedly an important component of our diet.

Richard Bramwell says:
3 January 2017

Cardboard – is that how you are getting fibre with NO added salt NOR sugar


Porridge oats, beans of various types, green vegetables, potatoes, etc. There’s plenty of fibre available without added salt and sugar.