BEE Harris-Benedict Calculator

Harris-Benedict Equation Explained

Basal energy expenditure (BEE), also called basal metabolic rate (BMR) is the amount of energy that the body requires to carry out fundamental metabolic functions, such as breathing, circulation or thermoregulation.

The Harris-Benedict formulas differ between genders because lean body mass is a major determinant of BEE and women tend to have more body fat and less lean muscle and as a result, their BEE is usually lower than that of comparable males.

BEE Formula Metric Units

BEE Male (kcal/day) = 66.5 + (13.75 × weight, kg) + (5.003 × height, cm) - (6.775 × age)

BEE Female (kcal/day) = 655.1 + (9.563 × weight, kg) + (1.850 × height, cm) - (4.676 × age)

BEE Formula English Units

BEE Male (kcal/day) = 66 + (6.23 x weight in lbs) + (12.7 x height in inches) - (6.8 x age in years)

BEE Female (kcal/day) = 655 + (4.35 x weight in lbs) + (4.7 x height in inches) - (4.7 x age in years)

Harris-Benedict Adjustment

The BEE can be adjusted by the level of activity of the subject so that a recommended caloric intake can be determined. The adjustments range from 20% increase of BEE for sedentary subjects to up to 90% increase of BEE for subject who exercise heavily:

• Sedentary (little to no exercise) = BEE × 1.2
• Light exercise (1-3 days per week) = BEE × 1.375
• Moderate exercise (3–5 days per week) = BEE × 1.55
• Heavy exercise (6–7 days per week) = BEE × 1.725
• Very heavy exercise (twice per day, extra heavy workouts) = BEE × 1.9

Summary of factors that influence BEE

1. Age: The basal energy expenditure varies with age. Whilst the peak is in infancy, the BEE declines rapidly through childhood and adolescence, then continues a steady decline. The decline in old age (which is not inevitable and can be influenced by activity levels and weight bearing exercises) is due largely to loss of muscle mass.
2. Gender: As mentioned in the previous section, women tend to have less lean muscle than men so thus a lower metabolic rate and consumption than men.
3. Body composition: Muscle tissue burns up to five times more calories than fat so the bigger the muscle mass, the higher the caloric consumption, even in individuals of otherwise, similar characteristics.
4. Body surface area: The greater the surface the higher the BEE, therefore tall and thin people tend to have higher BEEs.
5. Hormonal function: Thyroid or cortisol hormones are regulators of the metabolic rate, for example if they are too high, then the metabolic rate increases.
6. Eating habits: Dietary habits, starvation or long periods of dieting can decrease the BEE.
7. Certain medical conditions and medication: May affect the metabolic processes.
8. Heredity: There is some degree of genetic determinism in BEE levels.

References

Harris J, Benedict F A Biometric Study of Human Basal Metabolism PNAS.1918; 4 (12): 370–3.

Mifflin, MD; St Jeor, ST; Hill, LA; Scott, BJ; Daugherty, SA; Koh, YO A new predictive equation for resting energy expenditure in healthy individuals. The American journal of clinical nutrition. 1990; 51 (2): 241–7.