Basal Metabolic Rate is the minimal caloric requirement needed to sustain life in a resting individual.  This is the amount of energy your body would burn if you slept all day (24 hours).  

Factors that affect BMR:

Age:  In youth, the BMR is higher; age brings less lean body mass and slows the BMR. Height: Tall, thin people have higher BMR's.

Growth:  Children and pregnant women have higher BMR's.

Body Composition:  The more lean tissue, the higher the BMR.  The more fat tissue, the lower the BMR.

Environmental Temperature:  Both the heat and cold raise the BMR. Fasting/Starvation:  Fasting/starvation hormones lower the BMR.

Malnutrition: Malnutrition lowers the BMR.

Stress:  Stress hormones can raise the BMR.

Fever:  Fevers can raise the BMR.

BMR = your body weight in lbs  x  10 cal/lb

The Harris-Benedict Equation:

Males: 66 + (13.7 x W) + (5 x H) - (6.8 x A)                 Females:  655 + (9.6 x W) + (1.7 x H) - (4.7 x A)

Where: W = actual weight in kg (weight in lb/2.2 lb/ kg) H = height in cm (height in inches x 2.54 cm/in)        A = age in years

Resting Energy ExpenditureEnergy required for vital body processes and sedentary activities

Men:

66 + (6.23 x weight) + (12.7 x height) – (6.8 x age)

Women:

655 + (4.36 x weight) + (4.31 x height) – (4.7 x age)

very light light moderate heavy very heavy

Men: REE x 1.3 1.6 1.7 2.1 2.4

Women REE x 1.3 1.5 1.6 1.9 2.2

Calorie Needs

Body Weight (lbs) X 13 Sedentary/lightly active

16 Moderate Activity

20 Heavy Activity

25 Exceptionally Heavy Activity

Subtract appropriate number for age:

25 – 34………………..0

35 – 49………………..100

50 – 64………………..200