“Farewell” to the Calorie?

Tesco is phasing out ‘kcal’ from the nutrition information on food products. Only ‘kJ’ will be used. (Information provided by Philip Bladon, and edited by Derek Pollard).

Philip, a member of UKMA, has heard from Tesco that between now and the end of 2009 the use of kilocalories (kcal) as part of the nutrition information provided on its own-label food products will be phased out. From a SI point of view, Philip adds, “Every little helps!”.

Derek noticed during his recent visit to Australia that ‘kcal’ had disappeared from most food packaging, although it was sometimes found on imported food products. Magazine articles relating to cooking and slimming seemed to use only the SI unit, the kilojoule (kJ).

18 thoughts on ““Farewell” to the Calorie?”

  1. A good step I suppose, but Tesco has other priorities – they still sell their milk in pints primarily which is an utter pain, though I did notice that their ‘filtered’ range of milk is in litres completely.

    But apart from that, and on the whole I’m 99% satisfied with the UK retailing market and metric. Even my local butchers is completely metric – I could not see a single lb or oz. Even in the Daily Mail, the typical vanguard of imperial, prints their recipes in entirely metric most of the time.

    The only issue in the UK and metric IMO is road signage. Once that goes, I’m utterly convinced everything else will slot into position. Unfortunately, it seems to be taking an age. The pro-metric lobby must start getting creative with ways to push this because at the moment it’s stuck in a horrible stalemate with everyone blaming everyone else.


  2. Tesco are going to have trouble phasing out the Calorie as long as all the major health and dieting organisations work with that unit of energy. The “Calorie” is so much part of slimming culture that it gets used to mean “energy” (e.g. “high-calorie food” and “calorie-burning exercise”). If Tesco are going to be successful in changing to Joules then it’s going to take a big push with all the slimming organisations. They currently tell their customers how many Calories they should eat each day. It’s a classic chicken-and-egg scenario. The food packagers can’t change if the public are still working in Calories; and the public won’t change as long as the food packets give them Calories.


  3. Good on Tesco for taking this step and while I agree with Martin on the milk issue, the UK retail sector still isn’t perfect. Along with Tesco, Asda seem to be quite good on the metric front although they too sell milk in pints. I did recently however end up in my local Morrisons looking for 500g of minced beef and wound up buying a 453g pack instead. I also noticed with shock that McCain Oven Chips are still in lbs (the pack in my freezer reads “1.8kg e 4lb”) and from my research they’re a Canadian company!

    However, I’m in two minds as to wether this change will have any great effect. On the one hand it might be too small to notice given that the press and diet industry seem to refuse to change from lbs to kgs. On the other hand Tesco is big enough that its possible that a large enough number of peope will get so used to using kJ that things will have to change.


  4. I would most certainly welcome the removal of k-cal or Calories or calorie.
    We don’t need it.

    The calorie has a number of disadvantages. Firstly it is defined in terms of the thermal properties of water independently of other units in SI except for Celsius. As such, to reproduce it requires complex apparatus operating under very precise conditions.

    The joule on the other hand has a mechanical origin and is derived directly from the metre, kilogram and second . It exists purely by definition based on simple mechanical principles.

    The calorie can be a source of confusion. Exercise equipment sometimes have instruments that give an indication of the number of calories the user has expended. It is seldom (if ever) made clear whether it means dietary calorie (k-cal) or the basic calorie namely 0.001 k-cal! (I suspect the latter)

    The joule is unambiguous. The meaning of the symbols J and kJ are clear. There is no such thing as a ‘dietary’ joule.

    The joule is the modern SI unit of energy. It can be applied to all forms of energy be it mechanical, electrical or thermal.

    It is in fact the only unit that measures electrical energy (1 watt = 1 joule/second, 1 watt = 1 volt x 1 ampere).

    Thermal properties of materials can just as easily be expressed in terms of joule/degree temperature difference etc as it can in relation to that of water. The calorie relates to water (under a very narrow set of conditions) but it doesn’t offer any particular advantage in measuring thermal properties in a wider sense. These things are subject to huge variations and seldom yield simple round numbers in either calories or joules.

    So why not use the joule that has all those other advantages that the calorie lacks?


  5. I suspect that most people who use Calories in general are probably unaware of it being a metric unit. But given the choice of Calories or kiloJoules, we should prefer kJ to be used instead of the old kcal (Calories). But either way, at least the choices are metric only. There are no imperial units used to measure the energy of food.


  6. Sorry to annoy you, but in many metric countries like France the calorie is used every day and it allowed and predominate like

    Carrefour Pain de mie moelleux – 24 tranches, 500g
    (Carrefour sliced English loaf – 24 slices, 500g)

    Analyse nutritionnelle pour 100g
    Valeur énergétique : 294 kcal
    Glucides : 54,8 g
    Lipides : 4,6 g
    Protides : 8,3 g

    (Nutrition information per 100g
    Energy: 294 kcal
    Carbs: 54,8g
    Fats: 4,6g
    Protein: 8,3g)


  7. If joules are so good, then please tell me what the GDA of energy for an average man is? I know it is 2500 kcal so that is what I use. Everyone I know uses calories in general conversation and it is almost always used in food adverts e.g. One 125ml pot contains only 49 calories. I think Tesco are making a big mistake as, apart from a few wierdos like people in the UKMA, a majority of people in England use them.


  8. The GDA for an avarage person can equally well be expressed as 10 MJ

    As a matter of fact the calorie is a metric unit which makes most people “wierdos” by the reasoning suggested elsewhere on this blog.

    However it is now obsolete and unnecessary. We only really need the joule for energy. If anyone wishes to convert, 1 calorie = 4.2 J (hence 1 kilocalorie = 4.2 kJ)


  9. If the calorie is metric, then why abolish it when so many people use it. We should be thinking of what the general population wants, not just a few people who say they use the joule. Also, knowing that I can have 2000/2500 Kcal per day (woman/man) means I can space out energy intake easier. E.g. a meal containing 500 Kcal is a quarter of the guideline. It is for the moment, the preferred unit for a majority of people.


  10. I’m not really worried about calories. I’ve been 172 cm and 67 kg since leaving school over 60 years ago. But I really don’t like being called a weirdo for wanting to use a logical international system of measurement. Try calculating using 5 ft 7 3/4 inches and 10 stone(s) 7 pounds (lbs -from the French) 12 ounces (written oz for some reason) to see something REALLY weird!


  11. People use Calories simply because they are told about them on food packaging and by diet vendors. There is nothing special about Calories that make them easier or harder to use than joules. The fact is that they are obsolete because we measure energy in joules, so we ought to stop using them.

    Contrary to what several people have said, I don’t believe the Calorie is a metric unit. It is defined in terms of metric units (Celsius and kg), but it is not part of the SI. The yard and the pound are defined in terms of metric units too, but that does not make them metric. (1 yard = 0.9144 m and 1 pound = 0.45359237 kg by definition).


  12. As long as both are displayed on packaging, what’s the problem? It’s not as if a standard package (in either Imperial or metric units) gives a nice round figure in either kcal or kJ. All the Weight Watchers(R) Points(R) calculations are done using kcal and I can’t see what is basically an American company changing anything real soon.


  13. This is ridiculous. I see no reason why both cannot co-exist. It may be easier to scientifically define the joule over the calorie but in what way does that matter to the average consumer? As long as they know that 4.2 joules is approximately 1 calorie I don’t think they need to be able to define the two to over 100 decimal units or the number of photons of frequency, f, will be required to deliver that much energy.

    For the record, I use the joule everyday in calculations however when looking at the energy value of food I use the kcal almost exclusively.

    Oh, and for the user above who posted that the difference between a calorie and a kilocalorie is blurred. It is no different than the distinction between joules and kilojoules. Its just the kilo prefix. [Unfortunately, it is not as simple as that.  It is very common to write “calorie” when the author means “kilocalorie”.  It is further complicated by the distinction sometimes drawn between “calorie” (small c) and “Calorie” (capital c) – the latter in fact being a kilocalorie. – Ed]
    Finally, the calorie is easier for your average person to use. I have no problems adding up numbers to the sum of 10,000 in my head, as would be required to calculate my maximum daily intake of food borne energy in kilojoules. However, your average consume would rather just have to add up to 2500 using kilocalories. [Why?  10 MJ is a nice round number, easy to remember. – Ed]
    Personally I’m happy having both units of energy printed on my food.  [But why have two different units to measure the same thing?- Ed]


  14. 1. I recently visited the NHS website:-

    I used the search box on the home page and entered ‘kilojoule’ and ‘kilojoules’ and found there were NO results. Then I entered ‘calorie’, ‘calories’, and ‘kilocalories’ and these produced many references.

    The NHS should be using kilojoules.

    I’ve requested that a change be made and only the kilojoule (kJ) is used.

    2. The British Nutrition Foundation has a good poster for schools ‘Energy Balance?’ This uses only kilojoules, please see link:

    Click to access EN%20Poster%20Sept08.pdf

    Philip Bladon SI Metric-Matters


  15. I am a science teacher and use SI units in calculations. The metric system makes it easier to calculate as it works in multiples of 10.

    However i do not understand the obsession with phasing out imperial. Imperial units sre the best to use when baking, measuring body weight and even hieght. This is for a variety of reasons. primarily they are easier to remember. ounces are just perfect and easier to double the recipe. 8oz of sgar 4oz of butter etc is far easiier than 250 grammes etc. It is alos far easier to visualisde the doubling up.

    For measuring height the feet define people into categories. Below 5’6″ is short above 6″ is tall. Try doing this in cm. Worst still try gauing someones weight in kilogrammes… yuk!

    And a pint…. do not get me started. There is a history here.. well a pint is just about the righ amount of beer to drink. Small enough to ensure it does not go to flat and large enough to avoid needless trips to the bar!

    You know where you are with imperial. Loosing it would leave is culturally the poorer and far the worse for ready reckning things. Unless you want to calculate F=ma or covert metres to nano metres strick with the imperial..its just easier to work with for the common man. But I suppose the internet geeks will be upset if as a nation we do not conform!!

    Any way signing off..

    Matt Boutle 780Newtons, 195cm tall average speed 5metres per second and at the mment drinking a pint. The last bit is the only thing you will comprehend!


  16. Big picture time, Britisher pals. It’s inefficient and potentially error inviting to use the metric and imperial measurement systems side by side. Literally the worst of all worlds. An improvement, albeit slight, would be to return to Imperial, but obviously too late for that. And keep in mind that the US version of Imperial (USCS) differs in some respects from the imperial system still used in UK. You really have got(ten) yourselves into an unholy mess.
    So when you do give it best and fly the coop, getting up to speed in metric will be part of your learning curve. Unless you make repressive countries like Liberia, Myanmar or the United States your host country.


  17. ‘By the end of 2009 Tesco will phase out the use of kilocalories (kcal) as part of the nutrition information provided on its own-label food products’

    Another year has gone by and Tesco still hasn’t done it.


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