/ Food & Drink, Health, Shopping

Food labels – do we need calories and kilojoules?

A food label showing calories

Most of us know how to work with calories. I know I can consume around 2,000 kcal a day as a woman, and that men are recommended 2,500 on average. So will a law to add kilojoules to packaging confuse shoppers?

For years now, we’ve gotten used to seeing the energy content of food shown in calories (kcals), and most of us understand the concept. Recipes give energy information in calories, ready meals state how many calories they contain and, more recently, a number of restaurants have started to display the calorie content of their meals.

Simpler food labels

At Which?, we’ve been campaigning for simple food labelling that gives people the information they need to help them make healthy choices. Currently, most front-of-pack labelling gives the energy content of the food in calories and the sugar, fat, saturated fat and salt in grams.

This is great news for shoppers – especially as all the major retailers have now committed to traffic light labelling as well. This means that people will finally be able to tell at a glance whether the food they’re choosing is high, medium or low in various nutrients.

However, new EU legislation will now make it compulsory for food manufacturers to label the energy content of foods in kilojoules (kJ) as well as calories. At the moment, kJ are already provided on the back-of-pack labelling. But under the new rules, if there is a front of pack label, then the energy content will have to be displayed both front and back. Those that fail to do so will be breaking the law.

Over-packing the packaging

Although kJ may be the correct scientific way to represent energy, I question how useful it will be to people. After all, how many of us really know how many kJ we should consume a day, or how many kJ are in a kcal? When we asked over 2,000 people in an online poll last August, 61%  wanted to see kcal displayed on food labels by itself. An additional 22% wanted kcal and kJ displayed together, but only 1% wanted kJ alone.

Many food manufacturers have said they’re concerned that this extra information on the front of food packages may confuse people, as well as overcrowding the packaging. Obviously, in this matter, the manufacturers’ hands are tied.

As the legislation has passed, we will soon have to get used to seeing both kJ and kcals on food packaging. But even so, I think I’ll stick to using the kcals to make a quick and informed decision about whether to buy or not. Do you use kcals, kilojoules or both when choosing your food? Do you think the extra info will crowd the packaging, or provide useful information?

What information would you like to see on food packaging?

Calories (kcals) (62%, 190 Votes)

Both calories and kilojoules (28%, 86 Votes)

Kilojoules (kJ) (10%, 29 Votes)

Total Voters: 309

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We seem to have both kJ and kcal on a lot of labels at present. That’s fine but hopefully we will move to kJ when we finally make a move to complete metrication. Those who are attempting to lose weight can have over four times as many kJ as kcal 🙂

I don’t think anyone is going to confuse a calorie and kilocalorie (kcal) but the latter is often distinguished by using a capital: Calorie.


I don’t think anyone is going to confuse a calorie and kilocalorie (kcal).

I do not agree with that, it was only recently when the joules issue started that I even knew about the kcal. I had often wondered how we humans managed to live on such a small amount of power, I now know it is 1,000 times more.

Malc.Moore says:
29 January 2013

When buying food i have always had a glance at fat Content and amount of Calories yet another grey area if one is buying Tinned Food its per 100grams or 1/2 a tin.However the likes of Tesco;Asda etc have Raised prices so much on Tinned food i no longer buy as much tinned food as i did.The Food industry spends far to much on Colorful Packaging.On frozen fish why on earth such Colorful boxes. Fish is Fish one does not need such Colorful Packaging which must add a lot to the Manufacturing costs.


At least either unit is precisely defined and we know exactly what it means, unlike ‘portion’ which seems mean whatever you want it to mean.


The portion size will be on the label, perhaps in small print. By making the portion size small it may encourage you to think that choosing that product will help you lose weight.

Look at the ‘serving suggestion’ on the front of a packet and it might just be more than a portion. 🙂


“Although kJ may be the correct scientific way to represent energy, I question how useful it will be to people.”

So, scientists are not people?? That is a new one.

The law is already there, kJ is what it will be.
The only point to make is to get rid of the redundent units and get used to it.
This rather perverse idea that we should continue to burden ourselves with dual labeling on everything is something I fail to understand.
That there should be one set of units for scientists and another set of units for people is even more perverse.
The world is moving towards one set of units, we should try to join that world, not continue to live in our own little island of “this is how we like to be”.


I’m as fed-up with lack of progress with completion of metrication as you are Brian, but there is no need to twist Shefalee’s words. 🙂

In the run-up to decimalisation in 1971 we had prices shown in both the old and new system and pounds, shillings and pence disappeared not long after. Many foods show both kJ and kcal, so it should not be a major problem to phase out the old units, though I suggest this would best be done at the same time as we tackle other aspects of metrication. We had a lot of fuss about removal of leaded petrol and that is now long forgotten for the vast majority of the population.

Malc.Moore says:
30 January 2013

Your post is rather like the Americans use the word FASCIA on Cars when the majority know it as Dashboard plain daft.

Malc.Moore says:
30 January 2013

Common sense should tell you that metrication is not popular in the UK.