If you add up all the error margins in the article (and they don't even mention that the FDA allows published calorie counts to be off by 20%) you end up with a

If you add up all the error margins in the article (and they don't even mention that the FDA allows published calorie counts to be off by 20%) you end up with an error margin that makes the resulting number pointless. I know the hacker in you wants a number to measure but if you know anything about math at all you should concede that calculating numbers which such a high error margin is indeed pointless.