“A Calorie is a Calorie.” Or isn’t it? Nutrition writers love to throw around arguments about the state of the calorie, as if they're overturning centuries of caloric orthodoxy. Arguing about calories is a diet guru trope because it conflates the meaning of the word calorie with the effect of the source of the calorie, but the first time you hear it, it sounds meaningful and groundbreaking. Unfortunately, the statement is meaningless and tired. So let's all agree to a ceasefire on this one.
A google search on calories
That's a little embarassing. Nutrition has to be the only field where its practitioners are arguing over its basic unit of measurement. We don't hear cosmologist bloggers saying, "But what really IS a lightyear?"
And semantically of course, a thing is itself. A calorie can’t be not a calorie. In the immortal words of Gene Kelly and Donald O’Connor, “A rose is a rose, a Mose is a Mose, a toes is a toes, hooptie-dooby-doodle.”
The trendy contrarian argument, "A calorie is not a calorie," is based on the idea that a calorie's source matters. A calorie from fat is different from a calorie from carbohydrate, and is different from a calorie of protein. Each calorie may contain the same total amount of energy, but they are utilized differently when metabolized. They have different thermic effects. This is true. So in this context, a calorie isn’t a calorie.
But a calorie is a unit of energy – it isn’t defined by whether it’s eaten, it’s defined by the amount of heat generated when it burns. So yes, a calorie IS a calorie.
You can see how the argument can devolve. To say a calorie (1) isn’t a calorie (2) is to change the definition of a calorie (1). Basically, it just becomes a cyclical argument disintegrating into white noise.
When someone starts telling you what a calorie is or isn’t, we suggest covering your ears and screaming "AVOCADOS ARE A FRUIT. NO ONE REALLY CARES ABOUT THAT EITHER," again and again. Or taking the food from their hands and eating bites of it, repeatedly asking, "What about this calorie? Or this one? WHAT ABOUT THIS ONE?"
Join us next time, for "Fat doesn't make you fat" and its equal and opposite, "Fat does make you fat."