I have asked clients what their total caloric intake is like each day and the numbers they give me is sometimes very alarming. Some are obviously way too high and a lot of them are surprisingly way too low. Basal Metabolic Rate (BMR) is a number of calories your body needs each day to provide enough energy to perform vital functions. This number is what your body needs to perform those functions at rest. BMR for each person is a little different due to many factors. Some of these factors include, age, lean muscle mass, height, weight and sex.
So how do I figure out what my BMR is?
You can figure this number out a few different ways. Most people use a mathematical equation to determine their BMR. The most common equation is the Harris Benedict Formula. This equation is not 100% accurate but will give you a pretty good idea with a +\- of about 200 k/cal.
Harris Benedict Formula
Men: BMR = 88.362 + ( 13.397 x weight in kg ) + ( 4.799 x height in cm ) – ( 5.677 x age in years )
Women: BMR = 447.593 + ( 9.247 x weight in kg ) + ( 3.098 x height in cm ) – (4.330 x age in years )
Estimating Total Calorie Expenditure:
To estimate your total calorie burn each day you take your BMR or what you are burning at rest and add that to your activity each day.
Sedentary: Office Job, little to no exercise each day.
BMR x 1.2= Total Calorie Expenditure
Light Active: Job that involves walking throughout the day or 1-3 days of intense exercise for 20 mins
BMR x 1.3-1.375 = Total Calorie Expenditure
Moderate Activity: Exercising 3-4 days a week between 30-60 mins
BMR x 1.5-1.55=Total Calorie Expenditure
Heavy Activity: : Labor intense job like construction worker, farmer, landscaper or similar occupation or 5-7 days of 60+ mins
BMR x 1.7=Total Calorie Expenditure
Extreme Activity: Professional Athlete doing multiple training sessions a day, an intense labor worker working 10+ hours daily. Most people do not fall into this category.
BMR x 1.9=Total Calorie Expenditure
Example Client: Female, Office worker that works out 3 days a week for about 45 mins which puts her into the moderate activity category
38 years old, 5 ft 4 in (162.56cm), 162 lbs(73.48kg)
BMR: 447.593 + ( 9.247 x 73.48 ) + ( 3.098 x 162.56 ) – (4.330 x 38 )=1466.13 k/cal
Total Calorie Expenditure: 1466.13 x 1.5=2199.2 k/cal
Weight Loss: We take the Total Calorie Expenditure and we take 500 calories away from the total, which in this case would be 1699.2 k/cal per day. With a 500 calorie a day deficit you will create a weekly deficit of 3500 k/cal which is equal to 1 lb.
Maintain Weight: Intake Total Calorie Expenditure
Building Muscle: We take the Total Calorie Expenditure and we increase by 200-500 calories per day. I like to stay on the lower end of that range to ensure minimum fat gains.
