6 major factors affecting your calorie requirements

Your calorie requirements per day depends on six factors. The formulas for calorie calculations
I'm about to tell you take into notice of all six of these factors to get the most accurate estimate
possible.


1) Your basal metabolic rate (BMR)


BMR is the total number of calories your body burns for normal bodily functions, including
circulation, respiration, cell construction, digestion, temperature regulation and every other
metabolic process in your body. In short, your BMR is the total sum of all the energy used
for basic bodily functions, excluding physical activity.

Those basic functions usually make up the largest amount of your daily calorie consumption
 - about 2/3. BMR is at its lowest when  asleep,  and you’re not digesting anything.
It can also vary dramatically from person to person depending on genetics. We all probably
know someone who eats anything they want yet they never gain an ounce of fat. This type of
fast metabolism person has inherited a naturally high BMR.


2) Activities you do


Behind basal metabolic rate, your activity level is the second biggest factor in how many
calories you require daily. Simply, the more active you are, the more calories you burn.
Become more active and you'll burn much more calories. Sit on the couch all day long
and you hardly burn any.


3) Your weight


Total body weight and total body size are also major factors in the number of calories
you require. The bigger you are, the more calories you’ll require to keep your body going.


4) Your muscle mass (or lean body mass, LBM)


Total body weight follows with the number of calories you require, but sorting your total weight
into its lean and fat mass allows you to calculate your calorie needs even more accurately. The
higher your LBM, the higher your BMR will be.

This is a major factor when you want to lose body fat because it means the more muscle you
have, the more calories you will burn at rest. Muscle is metabolically active tissue, and it requires
very much energy to sustain it. The best way to increase your BMR is to increase your LBM. 
This is why you could say that weight training helps you lose body fat.



5) Your age


Metabolic rate slows down with age. Therefore, the number of calories you, as an average person,
require also goes down with age. Luckily, you can prevent and even reverse the age-related slowdown
in metabolism by developing more muscle through weight training and good nutrition.


6) Gender


Men usually need more calories than women. The average man has a maintenance level of 2800
calories per day. The average female requires only 2100 calories per day to maintain. The reason
for this difference is body weight and muscle mass differences between men and women; the average
man carries much more muscle mass than the average female and this explains the spread in calorie requirements between men and women. In exception are those genetically gifted individuals with
higher BMR.



Methods of determining caloric needs


There are many formulas you can use to determine your daily calorie needs using these six factors.
Any formula using lean body mass in the calculations will always be more accurate than one based
only on total bodyweight. However, even if you only have total body weight to work with, you can
still get a very accurate results.


The "quick" method (based on total bodyweight)


A fast and simple method to determine how many calories you need is to use your
total current weight times a multiplier for TDEE.

Fat loss = 26-28 calories per kg. of bodyweight
Maintenance (TDEE) = 33-35 calories per kg. of bodyweight
Weight gain = 40 to 44+ calories per kg of bodyweight

That is a very easy method to estimate caloric needs, but its most obvious flaws are not taking into
account your activity levels or body composition. If you’re extremely active, this formula underestimates
your calorie requirements.

Using this formula, a lightly active 50-year-old woman who weighs 105 kgs would have a TDEE
of about 3400 calories per day (105 X 33). Since almost all women will rapidly gain weight on
3000 calories per day, this illustrates another flaw in the quick formula – it will overestimate your
calories if your fat percentage is significantly higher than average.

Despite these drawbacks, the quick formula is a good way to get a quick ballpark
estimate, as long as your body fat is at an average level or below that.


On my next post I'll go more deeply in other methods of figuring out your caloric needs, whatever your
goals are. And regardless if these might come off as a little boring to you, don't still underestimate the importantness of this subject!
Keep going, until tomorrow!