LogFAQs > #974949388

Your body expends x amount of calories a day just to perform basic survival functions. Regulate body temp, contract muscles (especially your heart), and general cell division and tissue growth/repair.

how much x is varies from person to person but is in a general window based on age, sex, and other genetic factors. On top of this is y, the energy (calories) you expend doing things. Mostly moving, but also thinking to an extent.

Let's call how many calories you consume in a day z. If x + y = z, then your body is at an energy equilibrium of sorts.

If x + y < z, then you're expending less energy than you're taking in. Your body will store that excess energy as fat, causing weight gain.

and if x + y > z, then you're expending more energy than you're taking in. Your body will then tap into its reserve energy, which includes fat, which can lead to weight loss.

You'll often hear between 1500-2500 calories as how much a person expends naturally, not counting movement, exercise, or other activity. The actual number varies from person to person based on mainly genetic factors. You shouldn't try to burn that much energy in a day, nor should you starve yourself.