About BMR (Basal Metabolic Rate)
"Basal Metabolic Rate" (sometimes also called "Resting Metabolic Rate")
or BMR is an approximate calculation of how many calories you would need
to maintain your current weight if you did nothing but stayed in bed all
day. This calculation is really only accurate for a certain percentage
of people, because your actual BMR depends on other things such as body
fat percentage, etc. For this reason, we also show BMR at plus or minus
20 percent, so you can get a better idea of the range.
When computed with your "lifestyle" number, this gives your overall
calorie needs in a given day.