Harris-Benedict Equation: Calculation of Basal Metabolic Rate

Introduction

Mathematical Formula for Determining BMR

The Harris-Benedict equation, also known as the Harris-Benedict principle, is a mathematical formula that estimates an individual's basal metabolic rate (BMR). BMR represents the energy required to maintain vital bodily functions at rest.

Accuracy of the Equation

Studies have reported varying accuracy levels for the Harris-Benedict equation. For men, the highest accuracy was achieved in conjunction with two specific formulas: the Harris-Benedict 675 and 65 equations, respectively.

Calculation Formula

The Harris-Benedict equation can be used to calculate BMR using the following formula:

For Men:
BMR = 665 + (13.75 x weight in kilograms) + (5 x height in centimeters) - (6.76 x age in years)

For Women:
BMR = 655 + (9.6 x weight in kilograms) + (1.8 x height in centimeters) - (4.7 x age in years)

Example Calculation

Let's say you are a man weighing 180 pounds (81.8 kilograms), standing at 6 feet tall (182.9 centimeters), and 22 years old.

Using the formula for men, your BMR calculation would be as follows:

BMR = 665 + (13.75 x 81.8) + (5 x 182.9) - (6.76 x 22)

BMR = 5003 calories per day

Alternative Methods

In addition to the Harris-Benedict equation, there are other predictive equations that can provide approximate estimates of BMR, such as the Mifflin-St Jeor equation or the Katch-McArdle formula.