How Powerful Are You?

What’s that got to do with food? Well, food is the body’s basic source of energy, its fuel! Physiologists and nutritionists use kilocalories (kcal) to let us know how much energy our food contains. Let’s say your diet intake is 2400 Calories/day. Notice the big “C” in calorie. A food calorie or “Calorie”—the one you read about on packaged food products and in articles about nutrition—is the same as a kcal. So, if you consume 2400 Calories/day, you’re also consuming 2400 kcal/day. Now, one kcal is equivalent to 4184 joules or 4184 J, the SI unit for energy. Power is given in joules per second (J/s) or watts (W). What all this means is that your daily diet represents about 1 x 107 J/day, and since a day has 86,400 seconds, your average power is about 115 W, a little more than a 100 W light bulb.

How powerful are you if you eat four Cinnabons? One Cinnabon contains 2000 Calories.

Cameron, John R., Skofronick, James G., and Grant, Roderick M. Physics of the Body (Second Edition). Madison, Wisconsin: Medical Physics Publishing, 1999.