The Cunningham Equation

Basal Metabolic Rate

T  he Cunningham equation is method of calculating Basal Metabolic Rate. Its an accurate method used by athletes, but difficult to calculate correctly as you need your body fat percentage and muscle mass. The Harris-Benedict is another method, slightly less accurate but fine for moderately active people.

Step #1 Determine Resting Metabolic Rate

Sample trainee is 200 lbs at 5% bodyfat, so 0.05 equals 5% bodyfat

Take your weight in pounds and divide by 2.2 to get your weight in Kilograms (skip if you use metric). E.g. 200/2.2=90.91 kg

Next take your fat percentage and multiply by your mass in kilograms, this will give you your fat mass (FM) E.g. 90.91x0.05=4.55 kg

Subtract your (FM) from your total weight in kilograms to get your fat free mass (FFM) E.g. 90.91-4.55=86.36 kg

Now enter your (FFM) into this formula

RMR = 500 + [22 x (FFM)] E.g. RMR=500 + [22 x 86.36]
RMR=500 + 1,899.92
RMR=2,399.93 cal

Step #2 Determine the Thermic Effect of Food

If you eat a moderate protein diet your factor will be 0.10 (roughly 1g/lb of body weight), for a high protein diet your factor will be 0.15 (roughly 1.5 g/lb of body weight) .

TEF = RMR x factor (0.10 or 0.15) E.g. TEF=359.99

Do not add this to your RMR yet.

Step #3 Determine Activity Thermogenesis

The first part is to determine your Non Exercise Activity Thermogenesis (NEAT). You'll need to use one of these NEAT factors (or one in between, like 1.45):

1.2- 1.3 for bed- or chair-ridden individuals
1.4- 1.5 for sedentary occupation without daily movement
1.5- 1.6 for sedentary occupation with daily movement
1.6- 1.7 for occupation with prolonged standing
1.9-2.1 for strenuous work

RMR + NEAT = RMR x NEAT factor E.g. RMR+NEAT=2,399.93 x 1.45
RMR+NEAT =3,479.88

Now add in your TEF

RMR + NEAT + TEF = Non training day caloric needs E.g. RMR+NEAT+TEF=3839.86

Now determine your Exercise Related Activity Thermogenesis (ERAT)

For intense free weight lifting the Metabolic Effect of Training (MET)is 6. Use your total weight, including fat. For the duration use a decimal to represent the amount of time (45 min = 0.75, 90 min = 1.5).

ERAT = Body Mass x duration x MET E.g. ERAT=90.91 x 1.5 x 6

On training days you add in your ERAT number for your total calories

E.g.RMR+NEAT+TEF+ERAT = 4,659.05

Our sample trainee would eat 3,839.86 calories on a Non Training Day and 4,659.05 for a Training Day.

Round down to 3,800 and 4,600 and our sample trainee knows how much he needs to eat to maintain his weight.

Simply calculate your own numbers and add or subtract 250 calories depending on your goal. Maintain this change for two weeks and decide if you need to readjust. If you lost or gained weight, maintain for two more weeks until you are no longer losing or gaining, then add or subtract another 250 calories and continue this process until you reach your goal.