I got a bunch of emails about the calorie yesterday! It is a ridiculous system of measurement and I did my best with it in the comic, but here's the deal. Unlike every other system of measurement ever, the word "calorie" refers both to itself and a unit of measurement 1000 times greater (or smaller, depending on your point of view)! It's like this: "calorie" can refer to the amount of energy needed to heat one giant kilogram of water by one degree celsius OR it can also refer to the amount of energy needed to raise one tiny gram of water by one degree celsius. Plus, there's the term "kilocalorie", but as Wikipedia's calorie page notes, the term "kilocalorie" and "calorie" are interchangable when dealing with food energy.
This is compounded by the fact that some (but not all) people use a capital-C "Calorie" to refer to the kilocal, while others don't. On food labels in Canada, capital-C "Calories" are listed, but so are capital-F "Fat" and capital-S "Sodium", where it has no special meaning, so that's not really much help.
In the comic, I went with lower-case "calories", as having everyone capitalize it every time looked weird, especially in panel 2. Most people wouldn't notice anything wrong, and for those that did, I had Utahraptor clearly define his terms in panel 5, so that folks would know what we were talking about. Unfortunately, unless you have just spent a few hours researching the calorie, it's easy to get confused and think that the numbers are 1000 times too big - or too small.
It gets worse! It turns out that the amount of energy needed to increase the temperature of water depends on the initial temperature of the water you're dealing with. There's the 4 degree calorie, the 15 degree calorie, the 20 degree calorie, the "1/100th of the energy required to move water from 0 degrees to 100 degrees" calorie, the "this is the amount of joules we've just decided upon and that's THAT" calorie, and so on. All are around the same amount, but of course, there are times where you want specifics.
In conclusion, the calorie is dumb and we should all deal in joules which are precise and which map to every form of calorie anyway. Besides, replacing "I'm counting my calories" with "I'm judging my joules" sounds way more like something we should be saying in the year 2009! You know it's true