# Harris–Benedict equation

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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 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 kilocalorie intake number below the estimated maintenance intake of the equation.[citation needed]

## Step 1 – Calculating the Harris–Benedict 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)

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.[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

## History

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.