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Determination of the Resting Metabolic Rate (RMR) -
Mifflin-St Jeor equation

Basal Metabolic Rate plus estimation of daily calories needed


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

Results:
Your estimated Basal Metabolic Rate (BMR) is
kcal/day
.
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.

Background

Resting Metabolic Rate

The Resting Metabolic Rate (RMR) is closely related to the basal metabolic rate (BMR) and it 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.


Resting Metabolic Rate  (RMR) equations:


(RMR) kcal/day:
(males) = 9.99 x weight (kg) + 6.25 x height (cm) - 4.92 x age(years) + 5;

(RMR) kcal/day:
(females) = 9.99 x weight(kg) + 6.25 x height (cm) - 4.92 x age (years) - 161.
 

References:


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

Comments:
Frankenfield, David; Roth-Yousey, Lori; Compher, Charlene (2005). "Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults: A Systematic Review". Journal of the American Dietetic Association 105 (5): 77589. Link.

"An assessment of energy needs is a necessary component in the development and evaluation of a nutrition care plan. The metabolic rate can be measured or estimated by equations, but estimation is by far the more common method. However, predictive equations might generate errors large enough to impact outcome."

"CONCLUSIONS:  The Mifflin-St Jeor equation is more likely than the other equations tested to estimate RMR to within 10% of that measured, but noteworthy errors and limitations exist when it is applied to individuals and possibly when it is generalized to certain age and ethnic groups. RMR estimation errors would be eliminated by valid measurement of RMR with indirect calorimetry, using an evidence-based protocol to minimize measurement error. The Expert Panel advises clinical judgment regarding when to accept estimated RMR using predictive equations in any given individual. " 

"For members of groups that are greatly underrepresented by existing validation studies of predictive equations, a high level of suspicion regarding the accuracy of the equations is warranted."


Variance:

The resting and basal metabolic rate generally decrease with age or if there is a decline in lean body mass.  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.

Summary:
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:

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.

Thermic effect of food (TEF):
Rough estimation: TEF = Total calories consumed/day x 0.1
   Example: 2000 kcal diet.    TEF = 2000 x 0.1 = 200 kcal/day.

TEF of protein >>>carbohydrates>>fats.

Graphical representation:
total energy expenditure

Measurement versus predictive equations:


Direct measurement:  Method: direct or indirect calorimetry.
BMR:   Conditions: measured under very restrictive circumstances  and strict adherence to  protocols. This method is generally impractical in most cases. 
RMR:  less restrictive conditions and more easily obtained.  The resting metabolic rate is only marginally different from the BMR.

Predictive equations:
An alternative method is to use predictive equations that can provide a rough estimate of the basal or resting metabolic rate.  The basal or the resting metabolism is the largest component of the total energy expenditure (TEE).... usually 60 - 75%.  The RMR or BMR is usually at the higher end of this range for sedentary individuals (70-75%) and at lower the end for athletes. 

Error rate of predictive equations:


The various predictive equations for determining the resting or basal metabolic rates may significantly under or overestimate the total calories needed to maintain the current weight of an individual when combined with stress/activity factors that are selected by the user. This variance can approach 20% (over or underestimation) depending on differences in  body composition (lean versus obese),  actual activity levels (athletic versus sedentary lifestyle), and energy levels expended in thermogenesis.

Disclaimer

All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgment. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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