The calorie calculator determines daily calories needed by multiplying Basal Metabolic Rate (BMR) by an activity factor. BMR is the amount of energy expended per day while at rest in a neutrally temperate environment and is calculated with the Harris-Benedict formula.
Harris-Benedict formula:
- For men, BMR = 66.4730 + (13.7516 weight in kg) + (5.0033 x height in cm) – (6.7550 x age in years)
- For women, BMR = 655.0955 + (9.5634 x weight in kg) + (1.8496 x height in cm) – (4.6756 age in years)
The Harris-Benedict equations have been tabulated for values of weight from 25.0 to 124.9 kg, for stature from 151 to 200 cm, and for age from 21 to 70 years.
The Harris-Benedict equations remain the most common method for calculating BMR for clinical and research purposes. All of the variables used in the equations have sound physiologic basis for use in predicting BMR. Supplemental data from the Nutrition Laboratory indicates that the original equations can be applied over a wide range of age and body types. The commonly held assumption that the Harris-Benedict equations overestimate BMR in obese persons may not be true for persons who are moderately obese.
References:
1. DAVID C. FRANKENFIELD, et al. The Harris-Benedict Studies of Human Basal Metabolism: History and Limitations. Journal of the American Dietetic Association, Volume 98, Issue 4, April 1998, Pages 439-445. doi:10.1016/S0002-8223(98)00100-X
2. J. Arthur Harris and Francis G. Benedict. A Biometric Study of Human Basal Metabolism. Proc Natl Acad Sci U S A. 1918 December; 4(12): 370-373. PMC1091498
3. Kansas State University
