The Harris–Benedict equation (also called the Harris-Benedict principle) is a method used to estimate an individual’s basal metabolic rate (BMR) and daily kilocalorierequirements. The estimated BMR value is multiplied by a number that corresponds to the individuals’s activity level. The resulting number is the recommended daily kilocalorie intake to maintain current body weight.
The Harris–Benedict equation may be used to assist weight loss — by reducing the kilocalorie intake to a number below the estimated maintenance intake of the equation.
Step 1 – calculating the BMR
The original Harris–Benedict equations published in 1918 and 1919.[1][2]
| Men | BMR = 66.473 + (13.7516 x weight in kg) + (5.0033 x height in cm) – (6.7550 x age in years) |
| Women | BMR = 655.0955 + (9.5634 x weight in kg) + (1.8496 x height in cm) – (4.6756 x age in years) |
The Harris–Benedict equations revised by Roza and Shizgal in 1984.[3]
| Men | BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years) |
| Women | BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years) |
Step 2 – applying the Harris-Benedict Principle
The following table enables calculation of an individual’s recommended daily kilocalorie intake to maintain current weight.[4]
| Little to no exercise | Daily kilocalories needed = BMR x 1.2 |
| Light exercise (1–3 days per week) | Daily kilocalories needed = BMR x 1.375 |
| Moderate exercise (3–5 days per week) | Daily kilocalories needed = BMR x 1.55 |
| Heavy exercise (6–7 days per week) | Daily kilocalories needed = BMR x 1.725 |
| Very heavy exercise (twice per day, extra heavy workouts) | Daily kilocalories needed = BMR x 1.9 |