Harris Benedict equation - Determination of the basal metabolic rate (BMR)

Basal Metabolic Rate plus estimation of daily calories needed

Height: 0 cm (0.0 inches)
Weight: kg (0.0 pounds)
Activity Level:

Your estimated Basal Metabolic Rate (BMR) is
A rough estimate of the number of calories required per day based on your current activity level is:  0 kcal/day.
If you consume 0 kcal/day you would simply maintain your current weight assuming that you consistently maintained the same activity level.  If you completely eliminate any exercise (sedentary), you could consume 0 kcal/day without gaining weight.
Weight loss:  
The generally accepted rate of weight loss is 1 to 1.5 pounds per week or approximately 6 pounds per month.   If you eliminate 500 kcal per day from your diet (or approximately 3500 kcal/week), you should be on track to meet this degree of weight loss.
Note: there is approximately 3500 calories per one pound of fat (0.45 kg).

After subtracting 500 calories your new target (calories/day) would be -500 which should result in roughly one-pound of weight loss per week.
Variance:  predictive equations used to estimate caloric requirements may either under or overestimate the actual requirements.  Calculators that simply use body weight and do not take into account the amount of lean body mass which correlates strongly with the basal or resting metabolic rate will produce wider error rates.

 Using a range of +/- 15%, your estimated daily range to maintain your current weight based on your current activity level would be: 0 to 0 calories per day. Value listed above: 0 calories.

Subtracting 500 kcal from this range would result in the following -estimated range for weight loss - (-500 - -500 calories) per day.

If an individual has a much higher lean body mass and reduced body fat, consider using the middle to upper end of the range listed above, otherwise the lower to middle end of the range should be used for individuals with a greater body fat percentage.


Harris Benedict Equations:

BMR calculation for men (metric)
BMR = 66.47 + ( 13.75 x weight in kg ) + ( 5.003 x height in cm ) - ( 6.755 x age in years )

BMR calculation for women (metric)
BMR = 655.1 + ( 9.563 x weight in kg ) + ( 1.850 x height in cm ) - ( 4.676 x age in years )


Harris JA, Benedict FG. A biometric study of human basal metabolism. Proc Natl Acad Sci USA 1918;4(12):370-3.

Basal Metabolic Rate (BMR)

Basal metabolic rate (BMR) is the amount of energy required to maintain the body's normal metabolic activity, such as respiration, maintenance of body temperature (thermogenesis), and digestion. Specifically, it is the amount of energy required at rest with no additional activity. The energy consumed is sufficient only for the functioning of the vital organs such as the heart, lungs, nervous system, kidneys, liver, intestine, sex organs, muscles, and skin. 

The basal metabolic rate generally decreases with age or if there is a decline in lean body mass.  In order to maintain the resting metabolic rate as we age, requires regular strength
training in order to prevent loss of skeletal muscle. Activities that tend to increase muscle mass (lean tissue) such as body building or strength training  (anaerobic activities), will also increase the basal or resting metabolic rate.   Aerobic activities such as running, skating,  or rope jumping may improve endurance but have little effect on the basal or resting metabolic rate (see post-exercise expenditure below).  Other factors that may affect the BMR or RMR include stress, illness, hormone levels (e.g. thyroid), environmental (e.g. temperature or altitude) or any other factor that effects the normal functioning of one or more vital organs.

Lean tissue requires significantly more energy to maintain because of the increased level of metabolic activity. In contrast, fat tissue requires very little energy to maintain and has little influence on the resting or basal metabolic energy needs.

Greater lean body mass = Greater BMR or RMR.

Because individuals can increase their total lean body mass through strength training (corresponding increase in skeletal muscle), it is possible to increase the overall basal energy requirements at rest.

Post-exercise energy expenditure: the amount of additional energy (above the resting or basal metabolic needs) expended after an activity depends on the intensity and duration of the exercise session. More intense sessions tend to increase resting energy needs for longer time periods. These increased energy requirements occur during the cool-down phase and are short-lived. Sustained increases in the resting or basal metabolic rate can only be obtained through regular strength training routines that increase lean body mass.

Aerobic activity: short lived increases in RMR/BMR (cool-down period)
Anaerobic activity (regular): increases in lean body weight (LBW) --> Sustained increases in RMR/BMR.

Utilization: The baseline BMR or RMR can be used along with stress/activity factors to estimate the daily caloric needs of an individual - (Total Energy Expenditure (TEE)  (kcal/day)).   See error rate below.

Total Energy Expenditure (TEE)
The total energy expenditure (amount of calories needed per day) is composed of three primary factors: (1) Resting or basal metabolic rate   (2) Thermic effect of food  (3) Activities of daily living (ADL) - physical activity.


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