Calories are a unit used to measure energy. More specifically, they show us how much energy a food contains and how much energy our body needs to function, move, and maintain its basic functions.
Every day, we take in energy through the food and drinks we consume. At the same time, our body uses energy for things like breathing, blood circulation, digestion, keeping our body temperature steady, and physical activity.
The relationship between the energy we take in and the energy we use is called energy balance. When we take in more energy than we use, the body stores the excess (mainly as fat). When we use more energy than we take in, the body gets energy from its reserves.
That's why calories aren't “good” or “bad” — they're just a tool that helps us better understand how our body works.
