Thursday, 27 May 2010

On The Ridiculousness of the Calorie

I've just had a thought.

Not a stupendous world changing though, but a thought none the less.

I've been thinking about how ridiculous it is that the diet and food industries rely on calories so much. For starters the calorie counts that appear on the front of food packaging is actually kilocalories. Meaning that a food with 100 calories in it actually contains 100,000 calories. Deosn't sound quite so small when pu that way does it?

The second thing that I realised, and the main point of this post, is that the way the energy content of that food is calculated, the method they use to find out that food has 100 calories in it, really shouldn't translate to the energy the human body gets it's energy from that food.

From the scientific knowledge and experience, the way scientists usually find out how much energy something has is by burning it.

I've done a fair bit of calorimetry in my time and the procedure is usually this; you take an amount of the thing you want to find the energy content of. Then you set fire to it, and use the heat from it to heat up an amount of water. The you use a formula to work out how much energy it gave out when you burnt it. Which is actually the amount of energy taken in by the water that was heated up, which is never going to be the exact amount of energy the flame gave out because heat escapes. Even bomb calorimetry, which is basically the above procedure with as much insulation as possible can't really be really perfectly accurate.

so that 100 calorie biscuit? That's how much energy it gave out when it was set on fire.

Can anyone honestly tell me that the energy given out on burning of a food is directly transferable to the energy that my body gets from eating it? I really don't think so. The way the human body gets energy out of food is far more sophisticated than that; it involves digestion, absorption, electron transfers and the making and breaking of chemical bonds. I honestly don't see how that can in any way be equated with burning food.

The body doesn't burn calories the way you burn charcoal for a bbq, it just doesn't work that way.

So my thought for the day: societies reliance on calories as a measure of how much to eat is utterly ridiculous. And I for one will no longer pay attention to them.

1 comment :

  1. Sharing this one through the Fat Heffalump Facebook page. Some fantastic common sense there!