Frederick C. Hatfield, Ph.D., MSS International Sports Sciences Association
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Your BMR is the number of calories you'd burn over 24 hours while lying down but not sleeping. Your actual metabolic rate is estimated by adding the caloric cost of all the activities you engage in throughout the day to your BMR.
Men's BMR = 1 X Body weight (kg) X 24
Women's BMR = .9 X Body weight (kg) X 24
These formulas are reasonably accurate for people with average levels of body fat (i.e., 20% and 28% for men and women, respectively). One kg (kilogram) equals 2.2046 pounds. The higher your body fat percentage, the fewer calories you'll burn (lower activity level, and less muscle to burn calories). The lower your body fat percentage, the more calories you'll burn (bigger muscles burn more calories than little ones).
Thus, it becomes much easier to get rid of fat permanently by increasing your metabolic rate. You do this by increasing both your muscle mass and your activity level. You can (and SHOULD) gain muscle mass and lose fat at the same time. Never sacrifice muscle tissue during the fat loss process. Instead, build more muscle to burn more calories. You'll lose more fat faster, and you'll be more likely to keep it off.
Your actual daily calorie needs may vary slightly from the tabled values. To obtain a more accurate estimate, ask an ISSA-certified fitness trainer to assist you.
KEY TO READING THE CHARTS BELOW
Lean Clinical Percent Body Fat Levels
Factor Description Multiplier
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1 "Lean" Men + 10% -- Women + 14%
2 "Normal" Men + 14% -- Women + 18%
3 "Clinically Obese" Men + 20% -- Women + 28%
4 "Chronically Obese" Men + 28% -- Women + 38%
Average Daily Activity Level
To estimate your average activity level for a 24 hour period, read the INSTRUCTIONS below. You will easily be able to approximate the percentage that most closely describes your lifestyle. This percentage is used in the daily caloric expenditure charts below.
Instructions
For each of the 24 hours in one of your "average" days, determine your energy expenditure by reading the descriptions below. Then, multiply your hourly BMR (BMR divided by 24) times your energy expenditure. Then multiply that figure by your lean factor multiplier (see the table above). For example, if your hourly BMR equals 85 calories, and your activity level during that hour was light (300 % for men), then you simply multiply 85 times 3. Assuming your lean factor is 3 (see above), you then multiply 255 times .90. Your hourly caloric expenditure equals 229.5 calories.
Do this for each hour of the day, add all of them together, and that is your daily caloric requirement. Be SURE to apportion your daily calories over at least five meals, with each meal reflective of your UPCOMING caloric needs. For example, if you expect to train eat more; if you expect to take a nap, eat less.
ENERGY EXPENDITURE GUIDE
female male
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-22% -20% sleeping
-0.1 0% Lying down totally relaxed but not sleeping (this is your "basal metabolic rate")
180% 200% Very Light: Sitting, studying, talking, little walking or other activities.
270% 300% Light: Typing, teaching, lab/shop work, some walking.
360% 400% Moderate: Walking, jogging, gardening type job.
450% 500% Heavy: Heavy manual labor such as digging, tree felling, climbing.
540% 600% Exceptionally Heavy: Fitness-oriented weight training, aerobic dance, cycling or similar vigorous activities.
630% 700% Sports: Vigorous sports competition such as football, racquetball, tennis or other extended-play sports activities.
720% 800% All-Out Training: Extremely high intensity weight training with little rest between sets or exercises.
810% 900% Extended Maximum Effort: Extremely high intensity and high duration sports competition such as triathlon, cross country skiing or marathon.
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If you really want to get sophisticated, here is an example of how it's done hour-by-hour. If, however, you prefer to use averages, the tables below are quite accurate. You may have to adjust your personal caloric intake up or down a bit from these averages, however.
YOUR HOURLY CALORIE REQUIREMENT GUIDE
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AS AN EXAMPLE, LET'S SAY YOU WEIGHT 100 POUNDS...
100 Lean Factor 1 1091 / 24 hours = 45 cal/hour average.
Then, 45 X 200% (your average activity level for that hour)
= 45 X 2 = 90 ...This is your hour's caloric requirement
2 Less 5% = 85.5
M = 1091 ( 45 ) 3 Less 5% = 81
F = 982 ( 41 ) 4 Less 5% = 76.5
All of the values tabled below are based on the conventional method of estimating caloric requirements except that your day's AVERAGE activity level and your body fat percentage is factored into the calculation process (not simply total body weight), and may vary between individuals. Also, slight rounding error may occur.
