You can calculate your calorie needs in 3 easy steps
Calculating your caloric needs is more easy than you think. Just follow the steps mentioned below.
Step 1: Calculate BMR
Step 2: Use Harris benedict formula to calculate daily caloric needs.
Step 3: Calculate the calorie deficit need you need to lose weight (20% of the daily calorie needs)
Step 1: How to calculate BMR
The BMR formula uses the variables of height, weight, age and gender to calculate the Basal Metabolic Rate (BMR).
Use the formula below to calculate your BMR:
Metric BMR Formula
Women: BMR = 655 + ( 9.6 x weight in kilos ) + ( 1.8 x height in cm ) – ( 4.7 x age in years )
Men: BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) – ( 6.8 x age in years )
English BMR Formula
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) – ( 4.7 x age in years )
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.8 x age in year )
Case Example:
Calculate the daily caloric need of John, a 28 year old man, man weighing 76 kilograms with a height 178 cms.
Using the above formula for men:
Men: BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) – ( 6.8 x age in years )
Applying the equation above:
John’s BMR = 66 + (13.7 x 76 ) + (5 x 178) – ( 6.8 x 28)
= 66 + (1041.2) + 890 – 190.4 = 1806.8
Therefore Johns BMR is 1806.8 cals.
Formula 2 for calculating BMR:
The method outlined above is fairly accurate and can be used in people with average build.
However The Katch-McArdle Formula more accurate than other formulas because it factors in lean body mass to calculate BMR. This formula is usually used for those who have a very high amount of body fat or a high amount of muscle.
This gives a more accurate basal metabolic rate reading.
You need to know your lean body mass before you use this formula. To figure out your lean body mass, you simply need to know your body fat percentage. You can have your body fat percentage measured at a gym or at a physiotherapist’s office.
For example… if John weighs in at 76kg and has a body fat percentage of 16%, this means that his body is made up of 12.2kg of fat and 63.8 kg of lean mass.
Once you have calculated your lean body mass, use the formula below to get an accurate reading of your BMR:
BMR = 370 + (21.6 X lean mass in kg)
Step 2: Use Harris benedict formula to calculate daily caloric needs
The Harris Benedict Equation is a formula that uses your BMR and then applies an activity factor to determine your total daily energy expenditure (calories).
The activity factor:
To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:
| 1) If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.22) If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.3753) If you are moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.554) If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.7255) If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9 |
Case Example:
John’s BMR is 1807 cals, he is moderately active, what is his daily caloric expenditure?
Using the equation above:
If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.55
Therefore John’s daily caloric needs = 1807 x 1.375 = 2800 cals.
The only factor omitted by the Harris Benedict Equation is lean body mass. Remember, leaner bodies need more calories than average bodies. Therefore, this equation will be very accurate in all except the situations where there is too much muscle mass or too little lean mass i.e. very muscular people (will under-estimate calorie needs) and the very fat people (will over-estimate calorie needs).
However if you are not obese or too muscular , this formula will give your total daily energy expenditure.
Step 3: Calculate the calorie deficit required
The right calorie deficit is around 20% of your total daily requirement.
Therefore in the above example John’s daily calorie requirement is 2800 cals.
His caloric deficit = 2800 x 20/100 = 560cals
Therefore John must now reduce his calorie intake by 560 cals in order to burn fat.
So his daily intake must now be 2240 cals.