Getting rid of calories

I have in front of me a fairly typical processed food item, a delicious 200g bar of Cadbury’s Fruit and Nut chocolate. On the back of the label, along with the enormous barcode (barcode readers must be myopic – it is by far the biggest item on the back of the package), and lots of purple space, is a whole bunch of information on the nutritional value of this food item.

Wiser heads than mine have obviously determined what this table has to cover, given its similarity across all packaged foods. The table on this chocolate tells me the energy, protein, fat (saturated and total), carbohydrate (sugars and other), and salt content of five squares (a “serving” as far as Cadbury is concerned), and 100g (half the block). It also tells me what proportion of an average adult daily intake a serving of this delicious product would represent. So I know that five squares of this chocolate would give me 6% of my daily energy, and 15% of my daily saturated fat and sugar quota. Powerful stuff.*

One would have be some kind of dietary mathematician to actually make proper use of all this data for all the food that one might consume in an average day or week. I am not sure what expectations those who set up the requirements had of those who eat the chocolate. But they seem to have a very high opinion of eaters’ ability to make sense of the screed of small-printed data they are presented with on food items.

I am particularly interested in the information on energy content. The label tells me that five squares have 528kJ of energy in them. The internet, god bless it, tells me that 528kJ is about 126 calories (which I should actually write with a capital C, apparently), and that as an 85kg male, I would use around 2,400 calories a day without doing any particular exercise, with adult women burning about twenty percent fewer. So I can eat 100 squares of this chocolate (about two and a half blocks) and get all of my energy for a day.

Given the increasing overweightness of the nation, one might postulate that the energy information on these chocolate labels is not being appropriate absorbed or understood. I wonder whether a less complex label might be more useful – one that relates the energy in what you eat to the amount of exercise that you would need to do to burn off the food item you are about to/have just consumed.

For me, the archetypal 85kg man:

  • Doing nothing, as mentioned above, requires about 2,400 calories a day, or 100 calories an hour.
  • Moderate walking (at 5 km/hour) seems to require about 300 calories an hour, according to this very helpful website, or 60 calories per km
  • And jogging or running seems to use a number of calories equal to your weight in kilograms per km, so in my case 85 calories per km. (Although it doesn’t seem to use many more calories than walking, notice that you will be running faster than you are walking, so you will burn more energy overall).

So now we have:

Activity Energy required
Sitting on couch 100 cals/hour
Walking 60 cals/km
Jogging 85 cals/km

And we can change the chocolate label so that instead of expressing the amount of energy you get if you ate a serving (noting that many things, notably corn chips – have ridiculously small serving sizes), it says how much exercise you can do with that serving.

The chocolate label would say:

If you eat 5 squares of this chocolate (126 calories), to burn it off you would need to:

Activity Length
Eat nothing else An hour
Walk Two kms, or
Run One and a half kms

And it would be easy to include the same information for a 100g half block as well. If I ate half the block (~500 calories), I would need to:

Activity Length
Eat nothing else Five hours
Walk Just over eight kms, or
Run Just under six kms

Since the average person walks at about five kms an hour, eight kms would be about an hour and a half walking for half a block of chocolate. And a six km run would be around thirty five minutes of running at a normal ten kms per hour.

More useful, I think, because it is a lot more direct.

PS What I like most about this chocolate label is the sentence that says “Enjoy your favourite treats as part of a balanced lifestyle”. I figure that this was actually intended to say: “do not eat too much chocolate”. But once that was filtered through the food labelling bureaucracy and the subtleties and difficulties were endlessly debated, what comes out is that anodyne phrase. Are we really better off with this euphemism? Does it actually achieve its objective? It seems similar to me to “enjoy responsibly” that is written on alcohol labels, which I suspect means “don’t drink too much”, although it is also not particularly clear.

* The back of the packaging also contains, as usual, a list of ingredients. This reveals the startling (to me) fact that “Fruit and Nut” chocolate is actually literally that – one fruit (sultanas), one nut (almonds). Perhaps “Sultana and Almond chocolate” did not have the same ring.