How many calories does a person need? Here is how to tell:
First you need to determine your Basal Metabolic Rate (BMR) with the following equation. Your BMR is the total number of calories your body needs if you did nothing but lie in bed all day with no activity at all.
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)
- Note: 1 inch = 2.54 cm and 1 kilogram = 2.2 lbs.
Example:
Male, 27, 180lbs, 5’11"
66 + (13.7 x 81.81kg) + (5 x 180 cm) - (6.8 x 27 yrs) = 1903
Now to calculate in the calories you need for your activity level:
Activity Multiplier
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)
Extremely active = BMR X 1.9 (hard daily exercise/sports & physical job Or 2X day training, i.e marathon, contest etc.)
Example:
BMR = 1903, we’ll use 1.725 for a very active individual.
1903 x 1.725 = 3282
So, in this example you need 3282 calories per day to maintain your current weight.
To lose weight the best thing to do is to adjust it slightly, perhaps 500 calories less per day. Do it too much and you can loose muscle as well as fat. Which throws off the metabolism even more.
See why eating 800 calories a day is terrible?