About Basal Metabolic Rate

The basal metabolic rate (BMR) is the amount of energy needed while resting in a temperate environment when the digestive system is inactive. It is the equivalent of figuring out how much gas an idle car consumes while parked. In such a state, energy will be used only to maintain vital organs, which include the heart, brain, kidneys, nervous system, intestines, liver, lungs, sex organs, muscles, and skin. For most people, upwards of ~70% of total energy (calories) burned each day is due to upkeep. Physical activity makes up ~20% of expenditure and ~10% is used for the digestion of food, also known as thermogenesis.

BMR Equations Used

Mifflin-St Jeor Equation:
For men: BMR = 10W + 6.25H - 5A + 5
For women: BMR = 10W + 6.25H - 5A - 161

Revised Harris-Benedict Equation:
For men: BMR = 13.397W + 4.799H - 5.677A + 88.362
For women: BMR = 9.247W + 3.098H - 4.330A + 447.593

Katch-McArdle Formula:
BMR = 370 + 21.6(1 - F)W
where W is body weight in kg, H is body height in cm, A is age, and F is body fat in percentage.