1. Calculate your BMR (basal metabolic rate):
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years )
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in years )
2. Multiply your BMR by the appropriate activity factor, as follows:
Sedentary (little or no exercise): BMR x 1.2 Lightly active (light exercise/sports 1-3 days/week): BMR x 1.375 Moderately active (moderate exercise/sports 3-5 days/week): BMR x 1.55 Very active (hard exercise/sports 6-7 days a week): BMR x 1.725 Extra active (very hard exercise/sports & physical job or 2x training): BMR x 1.9
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 kilocalorie requirements. The estimated BMR value is multiplied by a number that corresponds to the individual'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 kilocalorie intake number below the estimated maintenance intake of the equation.
Step 1 – Calculating the Harris–Benedict BMR
|BMR calculation for men (metric)||BMR = 66.5 + ( 13.75 x weight in kg ) + ( 5.003 x height in cm ) – ( 6.755 x age in years )|
|BMR calculation for men (imperial)||BMR = 66 + ( 6.2 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.76 x age in years )|
|BMR calculation for women (metric)||BMR = 65.5 + ( 9.563 x weight in kg ) + ( 1.850 x height in cm ) – ( 4.676 x age in years )|
|BMR calculation for women (imperial)||BMR = 65.5 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years )|
The Harris–Benedict equations revised by Roza and Shizgal in 1984.
|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)|
The 95% confidence range for men is ±210.5 kcal/day, and ±201.0 kcal/day for women.
Step 2 – Determine Recommended Intake
The following table enables calculation of an individual's recommended daily kilocalorie intake to maintain current weight.
|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|
The Harris–Benedict equation sprang from a study by James Arthur Harris and Francis Gano Benedict, which was published in 1919 by the Carnegie Institution of Washington in the monograph A Biometric Study Of Basal Metabolism In Man. A 1984 revision improved its accuracy. Mifflin et al. published an equation more predictive for modern lifestyles in 1990. Later work produced BMR estimators that accounted for lean body mass.
- A Biometric Study of Human Basal Metabolism. J. Arthur Harris and Francis G. Benedict. Proceedings of the National Academy of Sciences. Vol. 4, No. 12 (December 1918): 370–373.
- A Biometric Study of Basal Metabolism in Man. J. Arthur Harris and Francis G. Benedict. Washington, DC: Carnegie Institution, 1919.
- The Harris Benedict equation reevaluated. A.M. Roza and H.M. Shizgal. American Journal of Clinical Nutrition. Vol. 40, No. 1 (July 1984): 168-182.
- Harris Benedict formula for women and men. GottaSport.com. Retrieved on 2011-10-27.