BMI or body mass index is to assess your body composition status that calculated from body weight (kg) by height (cm)2. BMI is the bases to calculate your nutrients requirements considering age and activities taken. BMR is the body metabolic rate which refer to the energy (basic) needed by the body to live without any activities. So our body requirements in nutrients is calculated by the BMI which already adding up the BMR.
Of course there is a very good correltion between the two and indeed, there are formulae to help you estimate BMR (or actually RMR-the resting metabolic rate) from BMI. A better correlation is with fat free mass (FFM). here is Cunningham's formula:
RMR = 370 + 21.6 x FFM. RMR is kcal/24 hrs.
FFM can be estimated using equations proposed by Grey (1989).
There are also prediction equations to calculate RMR from weight and height. EG for males aged 30-60: RMR (in MJ/24 hrs) = 0.048 x wt - 0.011 x ht + 3.670. Hope this helps.
BMI, or body mass index, is a statistical measurement of a person’s body weight that is based on both weight and height. It is used to determine what a person’s ideal weight is. In comparison, BMR refers to a person’s Basal Metabolic Rate, or the number of calories a person would burn in a day even if he or she did nothing but sit or lie in one place.
According to me BMI and BMR are very important measure of human health. BMI is a useful measure of overweight and obesity. The higher your BMI, the higher your risk for certain diseases such as heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.