What is BMR?
BMI or "Basal Metabolic Rate "is a number of calories your body would burn if you would rest in bed for the whole day, it is the total no. of calories that are spent to maintain basic body functions. BMR vary individualy and decreases with age. It is very important to know what your BMR is with and dieting plan. For instance, if you use BMR Calculator and find out that your BMI is 2000 kcal a day than you know that is the value your body will spend regardles of your activity level, those are calories spent on keeping you live on a daily basis. Knowing that your BMR is 2000 calories a day and that you curently eating for instance 4000 kcal means that additional 2000 kcal should be spent daily on physical activities, otherwise you will start gaining some fat. Of course, the whole concept of BMR and dieting is more complicated but you can surely download and use BMI Calculator to gauge your basal metabolism and use that information when planning our your diet.
BMR will decrease with age but there are ways to increase your basal metabolic rate significantly. Raising the level of physical activity and regular training will speed up your metabolism thus increasing your BMR. Eating more smaller meals through a day at similar intervals instead of one or two big meals which is common mistake can speed up your BMR as well.