Resting Energy Expenditure (REE)

Okay. Let’s find out how to determine the Resting Energy Expenditure (REE) also known as Resting Metabolic Rate (RMR). I like to call it REE.

REE is the minimum number of calories you need to maintain normal, basic body functions. This doesn’t include exercise. This is the energy you need during the day and night just to survive.

To determine REE I like to use the revised Harris – Benedict Equation, which in my humble opinion provides the number that is the closest to the real thing. All right. Here is the moment for me to ask the authors of this formula to excuse my dare because I revised it even further.

I’ll explain. In order to use this equation you will need three things: your height, your age (so far so good), and your total body mass. Total body mass is a sum of your lean body mass and your fat tissue. But since the fat tissue doesn’t require energy (it’s an energy itself) why feed it? So, instead of using total body mass in the formula I use lean body mass.

But how do you know your lean body mass? First, you need to find out what your body fat percentage is. You can do this in three ways: You can go and get calipers or body fat analyzer and use them to determine that value; If this is not an option then you can stop by your local gym and politely ask a trainer to help you with that. Most likely he/she will; Or you can use the table below. It’s not very precise since it’s based on your own perception of your body shape (and you are biased;-). But any way, feel free to use it:

Male; Female

Very lean
6; 12

Lean
10; 16

Normal
15; 22

Above average
20; 27

Overweight
25; 32

Now that you know (?) your body fat percentage you use this equation:

Total Body Mass – Total Body Fat = Lean Body Mass

Total Body Fat = Total Body Mass x Body Fat Percentage (as a decimal value)

Example: Let’s say you weigh 150 LB; You score 15% body fat

150 x 0.15 = 22.5 (Total Body Fat)

150 – 22.5 = 127.5 LB Lean Body Mass

But to use your lean body mass in the formula you need to convert this in to kg (kilograms). If you live in Europe or anywhere else where they use the metric system you already know this value. But if you know your lean body mass in LB only you need to do this:

Example: Let’s take the lean body mass value from above: 127.5

127.5 / 2.2 = 57.95 kg or appr. 58kg

Okay. You will also need your height in cm (centimeters) and age. If you use the imperial system then you need to convert inches in cm. One foot has 12 inch. One inch equals 2.54 cm.

Example: Let’s assume you are 5’5

5’5 = [(5 x 12) + 5] x 2.54 = 65 x 2.54 = 165.1 or appr. 165 cm

Now that you know these two values, one thing that’s left is your age. I guess you don’t need a formula for that. For the purpose of the example let’s assume you are 25.

Here is the (revised Harris – Benedict Equation) revised ;-)

Male: 88.362 + (4.799 x height in cm) + (13.397 x lean body mass in kg) – (5.677 x age)

Female: 447.593 + (3.098 x height in cm) + (9.247 x lean body mass in kg) – (4.330 x age)

Now, just for the example I’m going to apply the values from above for a male:

88.362 + (4.799 x 165) + (13.397 x 58) – (5.677 x 25) = 88.362 + 791.835 + 777.026 – 141.925 =

= 1515.298 or approximately 1515 Cal

There you have it. Your REE is 1515 Cal a day. This might seem like a lot of math but following the example it will be really easy. So, pull that calculator from the drawer and find out your REE now!

Then stay tuned for the next step..