For those interested, this is the Harris Benedict Equation used to calculate daily calorie needs.
A lot of these calculations are inaccurate for people that are either very muscular or fat! So the way I used it was to input my details as if I was ‘in shape’.
First you need to work out your Basal Metabolic Rate or BMR. This is a calculation of the calories you’d basically need if you stayed in bed for 24hrs! This is how many calories your body consumes to stay alive.
Here are the (revised*) calculations:
For a man, his BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)
For a woman, her BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)
These figures obviously do not take into account physical activity. To add that in you have to assess your activity level, select it from the following list and multiply the BMR by the figure given. A word of warning though!! Most people overestimate their physical activity, so it is advised to choose the category below the one that you think you are in, unless you’re absolutely certain you’re being honest with yourself.
Little to no exercise = BMR x 1.2
Light exercise (1–3 days per week) = BMR x 1.375
Moderate exercise (3–5 days per week) = BMR x 1.55
Heavy exercise (6–7 days per week) = BMR x 1.725
Very heavy exercise (twice per day, extra heavy workouts) = BMR x 1.9
Hey presto, now you have a rough idea of how many calories you need to consume in a day to maintain your weight.
*the original 1918 calculations were revised in 1984 by Roza and Shizgal.