The method of Calorie measurement has changed very little since the late 1800s. Basically, one places a portion of food in a device called a bomb calorimeter. The food is kept in a sealed container surrounded by water, and then burned using electrical energy. After the food is completely burned, one measures the water temperature to see how many degrees it was raised by the burning food. One calorie is the amount of energy needed to raise the temperature of one gram of water by one degree Celsius. One Calorie (capitalized), as referred to by nutritionists, is actually one kilocalorie which is equal to 1,000 calories (no caps).
I was visualizing this simple method of measuring. To me it seemed more rustic than scientific. After the process, all that remains of the measured food is carbon. I decided it would be interesting to create drawings with the carbon remains of different foods. So I measured my own foods and burned them. I kept out most of the oxygen so that I would achieve something closer to charcoal than ashes. To do this I sealed empty paint cans and punched a few small holes to prevent explosions. I notified the neighbors not to be alarmed by the ensuing hour of smoke. I then cranked up the heat and created my own carbon.
After the cans cooled, I was ready to draw with the charcoal. Drawing number one was made with 50 grams of pretzels. So 190 Calories (or .19 kilocalories) were burned to create drawing number one. Drawing number two was made with 50 grams of peanuts. So 284 Calories were burned to create drawing number two. And so on.