The U.S. Has embraced its use on food labels

 The U.S. Has embraced its use on food labels

 despite the adoption of the kilojoule by other nations as well as criticisms it’s received over the years (opponents dubbed the calorie  a “foolish food science” back in the early 20th century, while contemporary concerns criticize the practice of calorie counting).

Countries such as Australia and France use the kilojoule, a metric unit, on their food packaging to express a food’s energy content. One calorie is equivalent to 4.184 kilojoules (while 1 kilojoule is equivalent to 1,000 joules). 

Dara Ford, a professorial lecturer of health studies at American University, said she thinks we still use the calorie because of historical precedent, despite our use of the metric system on other parts of the nutrition label. 

“We are used to the calorie and its calculation does predate the joule and the kilojoule,” she said. “It’s one of the most well-recognized tools from a nutrition-education perspective.”

Why we still use the calorie: a British vs. French rivalry

A calorie is technically the amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius, and might be used in chemistry or physics research. 

But these calories are too small to measure food, health experts say, so companies technically use big Calories — with a capital C — on nutrition labels. This big Calorie, which is interchangeable with a kilocalorie, is equivalent to 1,000 small calories, and is the amount needed to raise 1 kilogram, or 1 liter, of water by 1 degree Celsius. An item that has 200 big Calories actually has 200,000 small calories. 

Many of us aren’t aware of this distinction, and when we discuss calories, as we are in this piece, we’re actually referring to big Calories.