What is a Calorie?

Everyone seems to be familiar with the term “Calorie”, but what exactly is a Calorie? Let’s go back to chemistry class and learn!

When we talk about calories, we’re talking about a unit of measurement. Just like pounds is one way to describe weight (e.g. that dumbbell weighs twenty pounds), calories is one way to describe energy (e.g. that sandwich provides 350 Calories worth of energy).

Specifically, a calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius. When we talk about the number of calories in food, we’re actually talking about kilocalories (kcals). Kilocalorie is quite the mouthful, so “Calorie” is used for short; but notice the capital C. So technically, one Calorie is 1000 calories. All of a sudden that sandwich has 350,000 calories! No wonder so many people don’t like math!

There are other units for measuring energy besides just Calories. If you’re traveling abroad, you may notice nutrition facts labels on foods that list kilojoules (kJs), or both kJs and kcals. For reference, one Calorie is equal to 4.184 kilojoules.

Calories aren’t "bad"! We need them to survive as we need energy to function. However, if you eat too many Calories, (more energy that your body requires) this will generally lead to weight gain. Got it?