Total Daily Energy Expenditure (TDEE) is a measure of the amount of energy you consume during the day. It is made up of your basal metabolic rate (BMR), which is the energy you use to stay alive and the energy you use to do everything else (walk, talk, eat, and exercise).
BMR varies from person to person and between the sexes. Men tend to have a higher BMR than women of equal weight and height. This is because men have less fat than women. Other factors that can affect BMR include:
Height,
Weight,
Age (BMR decreases approximately 2% per decade after age 20)
How your thyroid behaves (thyroxine is a regulator of TMB),
Diet (starvation diets lower your BMR)
Internal temperature,
External temperature,
· Physical exercise.
There are many ways to estimate the TDEE, but the most used are:
Quick and dirty (based on body weight)
The Harris-Bededict formula
The Katch-McArdle formula (where your lean body mass has been estimated)
We will use the following example for the calculations:
She is a 40 year old woman
5 ft 4 in = 1.63 m in height
150 lb = 68 kg weight
% Body fat = 32%
You want to lose weight.
The quick and dirty method:
Losing weight = 12 – 13 calories per pound of body weight
Maintenance = 15 – 16
To gain weight = 18 – 19
In our example, Our Lady should consume between 1800 and 1950 calories a day to lose weight.
The Harris-Benedict (HB) formula (when you don’t know your lean body mass)
As this method does not contain a variable for lean body mass, it will underestimate the caloric needs of the extremely muscular and overestimate the needs of the extremely obese. You must first calculate the BMR and then add your activity factor to determine the TDEE
Men: BMR = 66 + (13.7 x weight in kg) + (5 X height in cm) – (6.8 x age in years)
Women: BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years)
For our example, BMR = 655 + (9.6 x 68) + (1.8 x 163) – (6.8 x 40) = 1343 calories / day
The multiplied activity is estimated as follows:
Sedentary = BMR X 1.2 (little or no exercise, desk work)
Slightly active = BMR X 1.375 (light exercise / sports 1-3 days / week)
Modification. active = BMR X 1.55 (moderate exercise / sports 3-5 days / week)
Very active = BMR X 1,725 (intense exercise / sports 6-7 days / week)
Extremely active = BMR X 1.9 (hard daily exercise / sports and physical work or 2-day training, i.e. marathon, competition, etc.)
Our lady estimates that she is Slightly active, so her TDEE can be estimated at 1,375 x 1,343 = 1846 calories / day.
The Katch – McArdle (KM) formula (when lean body mass is known)
Men and women BMR = 370 + (21.6 x lean mass in kg)
Our lady has measured her% body fat at her local gym at 32%, so her lean body mass would be 68 x (100 – 32) / 100 = 46.24 kg
So your BMR = 370 + (21.6 x 46.24) = 1369
Your TDEE using this formula would be 1,375 x 1,369 = 1,882 calories / day
You can see that the KM and HB formulas produce very similar results of 1846 and 1882 calories / day, but this is just TDEE and needs to be adjusted because our lady wants to lose body fat. So how much could you reasonably reduce your caloric intake to lose fat? Well that’s like asking how long a piece of string is and it would easily fill another item (hmm, I could write that one someday!) However, as a general rule of thumb, you might consider cutting your calories 15-20% and increasing your exercise. include moderate workouts 3-4 times per week. You decide to cut your calories by 15%, so your total calories with all three methods are:
Questions and Answers = 1800
HB = 1569
KM = 1600
I can’t say for sure if you lost weight on any of these diets, but I’d like to bet that your results would be better with the last two methods than the first. If you are trying to lose body fat; Good luck.
