2 of the most accurate ways to calculate your daily caloric needs

As promised, here are more accurate ways to calculate your calorie requirements per day.
So let's continue!

Equations based on BMR.


A very accurate method for calculating Total Daily Energy Expenditure (TDEE) is to determine
basal metabolic rate (BMR) first, then multiply the BMR by an activity factor to determine TDEE.
There are two formulas you can use to calculate your BMR. The Harris-Benedict formula is the
one you will use if you don’t know your LBM (you don’t need body composition information to
use this formula). If you know your LBM, you should use the Katch Mcardle formula for the most
accurate result.


The Harris-Benedict formula (BMR based on total body weight)


This formula uses the factors of height, weight, age, and sex to determine basal metabolic rate
(BMR). This makes it more accurate than determining calorie needs based only on total
bodyweight. The only factor it doesn’t take into account is lean body mass. This equation will be
very accurate in everyone else but the extremely muscular (underestimates caloric needs) and the
extremely overfat people (overestimates caloric needs).

Men: BMR = 66 + (13.7 X wt in kg) + (5 X ht in cm) - (6.8 X age in years)
Women: BMR = 655 + (9.6 X wt in kg) + (1.8 X ht in cm) - (4.7 X age in years)

Example:
You are male
You are 30 yrs old
Your height 173 cm
Your weight 78 kilos
Your BMR = 66 + 1068 + 865 - 204 = 1795 calories/day
Now once you know your BMR, you can calculate daily caloric needs by multiplying your BMR
by the following activity factor.

Activity factor

Sedentary = BMR X 1.2 (little or no exercise, desk job)
Lightly active = BMR X 1.375 (light exercise/sports 1-3 days/wk)
Mod. active = BMR X 1.55 (moderate exercise/sports 3-5 days/wk)
Very active = BMR X 1.725 (hard exercise/sports 6-7 days/wk)
Extr. Active = BMR X 1.9 (hard daily exercise/sports & physical job or
2 X day training, marathon, football camp, contest, etc.)

Continuing with the previous example:

Your BMR is 1795 calories per day
Your activity level is moderately active (work out 3-4 times per week)
Your activity factor is 1.55
Your TDEE = 1.55 X 1795 = 2782 calories/day


Katch-McArdle formula (BMR based on lean body weight)


The Harris-Benedict formula also has separate methods for calculating the needs of men and women because men usually have a higher lean body mass and a larger bodies. Since the Katch-McArdle
formula accounts for LBM, this single formula applies equally to both men and women and it is the
most accurate method of determining your daily calorie needs.

BMR (men and women) = 370 + (21.6 X lean mass in kg)

Example:
You are male
Your weight 78 kilos
Your body fat percentage is 14% (10,9 kgs fat, 67,1 kgs lean)
Your lean mass is 67.1 kilos
Your BMR = 370 + (21.6 X 67.1) = 1819 calories

Again, to determine your daily calorie expenditure from BMR, you simply multiply BMR by the
activity factor:

Continuing with the previous example:
Your BMR is 1819
Your activity level is moderately active (you work out 3-4 times per week)
Your activity factor is 1.55
Your TDEE = 1.55 X 1819 = 2820 calories


As you can see, the difference in the TDEE as determined by both formulas is statistically
insignificant (2782 vs. 2820 calories) because the man we used as an example is average in
body size and body composition. The primary benefit of factoring LBM into the equation is
increased accuracy when your body composition leans to either end of the spectrum (very
muscular or very obese). This is yet another reason to monitor your body fat percentage and
not just your body weight.



Adjust your caloric intake according to your goal


Once you know your maintenance level, the next step is to adjust your calories according to your
primary goal. And as I established on my earlier post, the mathematics of weight control are simple:

1) To keep your weight at its current state, you should remain at your daily caloric maintenance level.

2) To lose weight, you need to create a calorie deficit by reducing your calories slightly below your
    maintenance level (or keeping your calories the same and increasing your activity above your
    current level).

3) To gain lean body weight, you must increase your calories above your maintenance level (and
    engage in a program of progressive resistance training).



How to adjust your calories for fat loss


Now, let’s talk about how many calories you should consume to lose body fat. A calorie deficit
that’s too large or maintained for too long, will eventually wake up the starvation response and
slow down your metabolism. Still, you must be in a calorie deficit if you want to lose fat. The secret
is to use just a small calorie reduction and to avoid those "magic diets" that advertise for extremely
large calorie reductions.

Body fat is nothing more than stored energy in our body. To release that energy, you must enter a
calorie deficient state. Calories not only count, they are the most important variable in a fat loss
program. Simply enough, if you eat more calories than you burn, you will not lose fat, no matter
what you’re eating or how much of training you’re doing. Some foods may get stored as fat more
easily than others because of the way they affect your hormones and blood sugar, but always
remember that too much of anything will get stored as body fat. You can never override the laws
of energy balance


In a kilo of stored body fat, there are 7700 calories. So in theory, if you create a 3800-calorie
deficit per week through diet, exercise or a combination of both, you will lose about 0,5 kgs.
If you created a 7700 calorie deficit in a week you will lose a full kilo. The calorie deficit can
be accomplished through diet, exercise or better yet, with a combination of both. And as we
already factored in the exercise deficit by using an activity multiplier, the deficit we are concerned
with here is the nutrition deficit.

The strictly mathematical model of calories in versus calories out doesn’t always work because of
the body’s weight regulating mechanism – also known as the starvation response. Nevertheless,
the mathematical model gives you a very good starting point, and as long as you follow the
8 strategies you learned in my earlier post, for avoiding the starvation mode, you will continue a
steady, permanent fat loss by using a small, temporary calorie deficit in conjunction with aerobic
exercise and weight training.