Ecuation of Harris-Bendedict – Wikipedia, free encyclopedia
The Harris-Benedict equation It is an empirical equation to estimate the basal metabolism of a person based on their body weight, height and age, and is used in conjunction with physical activity factors, to calculate the daily consumption recommendation of calories for an individual. The equation is a normal body composition, with an average relationship between muscle mass and fat mass, so it can be inaccurate for people who are very muscular (the formula underestimates real needs) or for overweight people (the people overestimate equation the real needs).
Basal metabolic rate calculation [ To edit ]
Original 1918 equations [ To edit ]
The original Harris-Benedict equations published in 1918 and 1919: [ first ]
| Men | TMB = 66.4730 + (13,7516 x weight in kg) + (5,0033 x height in cm) – (6,7550 x age in years) |
| Women | TMB = 655.0955 + (9,5634 x weight in kg) + (1,8449 x height in cm) – (4,6756 x age in years) |
These equations are tabulated for weight values between 25 and 124.9 kg, height between 151 and 200 cm, and age between 21 and 70 years.
A simpler version with a very small error are the following equations:
| Men | TMB = 66.5 + (13.8 x weight in kg) + (5 x height in cm) – (6.8 x age in years) |
| Women | TMB = 655 + (9.6 x weight in kg) + (1.85 x height in cm) – (4.7 x age in years) |
Equations reviewed in 1984 [ To edit ]
The Harris-Benedict equations reviewed by Roza and Shizgal in 1984: [ 2 ]
| Men | TMB = 88.3620 + (13,3970 x weight in kg) + (4,7990 x height in cm) – (5,6770 x age in years) |
| Women | TMB = 447.5930 + (9,2470 x weight in kg) + (3,0980 x height in cm) – (4.33 x age in years) |
A simpler version with a very small error are the following equations:
| Men | TMB = 88 + (13.4 x weight in kg) + (4.8 x height in cm) – (5.7 x age in years) |
| Women | TMB = 448 + (9.3 x weight in kg) + (3.1 x height in cm) – (4.3 x age in years) |
Equations reviewed in 1990 [ To edit ]
The Harris-Benedict equations reviewed by Miflin and St Jeor in 1990: [ 3 ]
| Men | Tmb = (10 x weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5 |
| Women | Tmb = (10 x weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161 |
Daily calorie intake according to the Harris-Benedict principle [ To edit ]
The following table allows the calculation of the daily calorie intake of a person to maintain their current weight: [ 4 ]
| Little or no exercise | Necessary daily calories = tmb x 1.2 |
| Light exercise (1-3 days a week) | Necessary daily calories = tmb x 1,375 |
| Moderate exercise (3-5 days a week) | Necessary daily calories = tmb x 1.55 |
| Strong exercise (6-7 days a week) | Necessary daily calories = tmb x 1,725 |
| Very strong exercise (twice a day, very hard training) | Necessary daily calories = tmb x 1.9 |
Harris-Benedict formula history [ To edit ]
In 1919, the Nutrition Laboratory of the Carnegie Institute of Washington (USA), publishes a monograph with the title “A Biometric Study of Basal Metabolism in Man” . The authors of this publication were the physiologists-nutritionists J. Arthur Harris and Francis G. Benedict.
In this Harris-Benedict monograph they evaluated metabolic parameters of 136 men and 106 women, all healthy adults. These subjects were performed indirect calorimetry and from the evaluation of their data with regression analysis, mathematical formulas were designed to predict restless energy expenditure, using as variables the age, gender, weight and size.
In 1984, the data and the original Harris and Benedict formula were re-evaluated by Roza and Shizga determining the total active cell mass with total body potassium measurements (KE). Based on their results, they proposed some variants to that original 1919 formula.
In 1990, Pellet published in the American Journal of Clinical Nutrition A complete review of the mathematical formulas used to predict resting energy expenditure. In this publication appears an update of the original Harris and Benedict formula that is used today.
Uses to lose weight [ To edit ]
If we use the last formula described in the tables, a 24 -year -old man, 80 kg and 180 cm, it turns out to have a basal metabolic rate (TMB) of 1.810. If you also practice exercise moderately, the TMB should be multiplied by its level of activity (1,810 x 1.55). We obtain 2,805 kcal per day to maintain its current weight of 80 kg. Although this seems a high calorie intake, it is what its level of precise activity. This individual would not lose weight if it maintains their level of activity and intake. The same person could only consume 2,172 kcal per day without gaining weight in the event that he did not perform any exercise.
Using the Harris-Benedict equation, you can adapt the calorie to lose weight. A kilogram of body fat contains approximately 7,000 kcal. [ 5 ] According to the Harris-Benedict equation, if someone with a TMB of 2,500 kcal consumes only 2,000, it should lose 1 kg of fat in 14 days under the assumption that the caloric deficit only compensates for oxidizing fat.
See also [ To edit ]
References [ To edit ]
external links [ To edit ]
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