What is Basal Metabolic Rate (BMR)
Your body burns through calories even at rest. Basic human functions like breathing, repairing muscle tissue, cell regeneration and renewal and the processing of nutrients uses a tremendous amount of energy.
Your BMR is the number of calories that your body needs in order to fulfil all of these functions.
As you age, your BMR will fall and so will your TDEE. You can calculate your TDEE using our TDEE Calculator here.
Note that BMR is different from RMR, which you can find out more about and calculate using our RMR Calculator
Calculating your basal metabolic rate and caloric needs
One of the most important things to do when embarking on a training plan or new diet is to calculate your caloric requirements. The main number you will need to find is your basal metabolic rate (BMR).
Calculating your BMR
It’s easy enough to find a rough estimate of your BMR. Though actual amounts will vary according to person - there are too many variables to take into account to be 100% accurate all the time - a simple BMR calculator will be able to put you in the right ballpark.
Alternatively, you can do it yourself using a simple enough equation. This is called the Harris-Benedict equation, and it goes like this:
For women: BMR = 655 + (9.6 × weight in kg) + (1.8 × height in cm) – (4.7 × age in years)
For men: BMR = 66 + (13.7 × weight in kg) + (5 × height in cm) – (6.8 × age in years)
Why your BMR is so important
Once you know your Basal Metabolic Rate, any changes you want to bring about in your body become suddenly much more achievable.
We’re always being told that weight loss requires a caloric deficit, and that weight gain requires a caloric surplus. Knowing exactly how much food to eat to achieve any deficit, surplus, or even maintenance, requires knowing how much energy your body uses: your BMR.
In short, you can use your BMR to aid in weight loss, gain or maintenance.
How many calories your lifestyle demands
Once you’ve got your BMR, you need to multiply it by your activity level. This will make sure that you allow for the extra calories needed for things like walking around, playing sports, training and rebuilding muscle through hypertrophy.
To include the number of calories you burn during daily activities based on your lifestyle, use the following multiplications:
Sedentary: If you get little or no exercise, multiply your BMR by 1.2.
Lightly active. If you lightly exercise one to three days per week, multiply your BMR by 1.375.
Moderately active. If you moderately exercise three to five days per week, multiply your BMR by 1.55.
Very active. If you take part in hard exercise six to seven days per week, multiply your BMR by 1.725.
Extra active. If you engage in very hard exercise six to seven days per week or have a physical job, multiply your BMR by 1.9.
The number you get is the number of daily calories you need in order to maintain your current weight. Obviously, these are rough guides, so you may need to play around with the numbers to better suit your needs as you go along.
If your goal is to maintain your current weight, eat this amount. Add 500 calories to the total to gain around 1lb per week or deduct 500 calories to lose roughly 1lb per week.