Make Sense of Calories and Why They Matter

3. How Does Our Body Use Calories?

When we think about calories, we often think about exercise, but everything your body does requires energy or calories, including involuntary activities like sleeping and the beating of the heart that pushes blood through the body.

The process of converting meals to energy is metabolism. The metabolic process adds oxygen to the nutrients we ingest, converting them to energy. The amount of calories that someone needs just to function, without any added activity, is their basal metabolic rate.