We can describe metabolism as a group of processes transforming substances into energy.
Basal energy expenditure (BEE) has a value we can obtain by calculating the basal metabolic rate (BMR) for 24 h. These values tell you about the number of calories your body "consumes" for its basic, life-sustaining needs.
We can compute both BEE and BMR using, e.g., Harris-Benedict or Mifflin-St. Jeor equations. Read more