Resting Metabolic Rate (RMR) is the number of calories (kcal) burned at rest to sustain life. Pretty important then I guess? That's why we are now measuring it!! Every major bodily function involves the metabolism, from breathing to brain function. Variables such as age, sex, muscle mass and activity levels all affect your RMR. RMR is responsible for up to 70% of your total energy expenditure. Your brain alone uses roughly 300kcal a day?! Two other things make up the remain