Basal Energy Expenditure...Coolest Math You'll Ever Do!

Many people assume they burn a certain amount of calories a day.  Wouldn't it be great to know for real?  The Basal Energy Expenditure equation also known as the Harris-Benedict equation, tells you exactly how many calories you burn at rest per day.  Depending on your gender, there are two equations to choose from to get your Basal Metabolic Rate (BMR).

For Men:

BMR = 66.5 + (13.75 x weight in kg) + (5.003 x height in cm) - (6.775 x age in years)

For Women:

BMR = 655.1 + (9.563 x weight in kg) + (1.850 x height in cm) - (4.676 x age in years)

*Equation information retrieved from http://www-users.med.cornell.edu/~spon/picu/calc/beecalc.htm

In case you need some help figuring out your weight in kg, take your weight in pounds and divide it by 2.2 to convert to kg.
For height in cm, take your height in inches and multiply it by 2.54 for cm conversion.
If you need help figuring out your age in years, call your mom. :)

So, here's a trial run.  Say you are a 225 lb, 75 in., 26 year old male.  Using the handy-dandy conversions I provided, change your weight and height to kg and cm. 

225 lb. / 2.2 kg/lb = 102.27 kg
75 in * 2.54 cm/in = 190.5 cm

Now, time to make magic:

Using our equation for men:

BMR = 66.5 + (13.75 x weight in kg) + (5.003 x height in cm) - (6.775 x age in years)

Put in our information:

BMR = 66.5 + (13.75 x 102.27kg) + (5.003 x 190.5cm) - (6.775 x 26 years old)

BMR = 66.5 + 1406.21 + 953.1 - 176.2

BMR = 2249.61

What does 2249.61 mean?
     Well, since Basal Metabolic Rate (BMR) is the base amount of calories expended per day at rest (aka doing nothing but sitting on the couch), 2249.61 is the amount of calories a 225 lb, 75 in, 26 year old male burns doing absolutely nothing during the day.  Any form of caloric expenditure during the day is added to that BMR number to make it higher.  In order for this man to maintain a healthy weight, he would have to make sure that he eats less than his BMR if he does nothing all day, or keep his caloric intake under his total energy expenditure if he works out, moves around, studies, etc.

If you're a woman and want to figure out your own BMR, use the equation for women and go from there!  I hope this brought some cool insight to your fitness life and helped with making math kind of cool, too!