How To Calculate Your BMR and TDEE

Learn To Manage Your Own Health and Wellness

It is of vital importance to your health and wellness journey to learn, understand and master all the information you can on food intake as energy, energy expenditure, and energy balance. The primary focus should be around learning how you metabolize food energy and how to properly nourish your body. My hope is that this article will help build a basic understanding of Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). This is to help understand how energy is utilized by the body and how much you should consume in a given day to get the results you plan on achieving from fat loss, maintenance, or to gain muscle.

What is known is that many people drastically under-estimate the caloric value within foods consumed while at the same time also over-estimating their work output and exercise-related caloric use. This leads to eating far too much while at the same time burning far too little.

This fundamental disconnect is what leads to the health epidemics of obesity, diabetes, and cardiac arrest. The United States and many other countries have suffered the consequences of bad or no nutritional and physiology being taught or understood by the general populace.

In this post, we will be covering building an estimate of your calorie use in a day and how you can use this data to help manage a weight loss plan, maintenance plan, or mass gain plan.

Understanding Basal Metabolic Rate

What Is BMR?

BMR stands for Basal Metabolic Rate and is a measure of how much energy your body utilizes while fully idle. This would mean being in a physically and psychologically undisturbed state, in a heat neutral environment, and while not actively digesting food. To put it simply this is the very primal level of just surviving, so it is only the first step in learning about your body energy use.

How To Calculate Basal Metabolic Rate

There are multiple methods over the years that have been made available to calculate your BMR. Each uses just a couple of specific input variables. Our preferred method though utilizes your lean body mass number as this will be more precise area and approximation.

  • Revised Harris-Benedict Equation
    • 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)
  • Mifflin St Jeor Equation
    • Men: (10 x weight in kg) + (6.25 x height in cm) – (4.92 x age) + 5
    • Women: (10 x weight in kg) + (6.25 x height in cm) – (4.92 x age) – 161
  • (Preferred) Katch-McArdle Formula
    • BMR = 370 + (21.6 * (LBM in kg))
  • Aragon BMR Equation (Very Fast and Close) [ Good for Men and Women with Same Equation]
    • METRIC: 25.3 x lean body mass in kg
    • IMPERIAL: 11.5 x lean body mass in pounds

Comparing the Equations

Let’s see how these formulas compare to one another. We’ll use “Sean” as an example. Sean is…

  • 154 Lbs (70 kg)
  • 10% body fat
  • 5’9″ (175 cm)
  • 25 Years Old

Here are his BMR base level existence calorie estimates from the formulas above:

  • Katch-McArdle: 1731
  • Mifflin-St Jeor: 1676
  • Revised Harris-Benedict: 1760
  • Aragon: 1594

If you looked at the above you see each of these formulas are within 200 calories of each other. Since this is just an estimate and will need some modification and evaluation, it makes sense to use the Aragon formula and save yourself a few minutes if time-strapped.

Since you now understand how to estimate your basal metabolic rate. Let’s move forward to calculate how many calories you burn through formal exercise and daily movement.

Understanding Total Daily Energy Expenditure

What is TDEE And Why Does It Matter?

Total Daily Energy Expenditure (TDEE) is approximately the number of calories you burn in a day. This measure is best estimated by scaling your Basal Metabolic Rate (BMR) to your level of physical activity. TDEE is critical in building a proper nutrition plan to accomplish your desired fitness goals. 

How To Calculate TDEE

After you’ve estimated your BMR above, you can apply one of these physical activity factors to estimate your total daily energy expenditure.

  • Sedentary (little or no exercise, desk job) – BMR x 1.2
  • Lightly Active (light exercise/sports 3-5 days/week) – BMR x 1.3-1.4
  • Moderately Active (moderate exercise/sports 3-5 days/week) – BMR x 1.5-1.6
  • Very Active (hard exercise/sports 6-7 days per week) – BMR x 1.7-1.8
  • Extremely Active (very hard daily exercise/sports and physical job or 2/day training) – BMR x 1.9-2.0

How To Use This Data For Results

How do you put all this information into practice to give quality results? Below we explore 3 different paths and the approximate calories of our fictional character.

Sean is an office worker and mostly sedentary in his life. Since this is his activity level we can do the following to get his TDEE:

 

How To Lose Fat With Your TDEE

  • BMR: 1731 
  • Activity Level – Sedentary: 1.2 Multiplier
  • Lose Fat Multiplier: 25%

TDEE: 1731 * 1.2 = 2077 kcal

25% Caloric Deficit: 2077 * (1 – .25) = 1558 kcal 

How To Maintain With Your TDEE

  • BMR: 1731 
  • Activity Level – Sedentary: 1.2 Multiplier

TDEE: 1731 * 1.2 = 2077 kcal

How To Gain Mass (Muscle) With Your TDEE

  • BMR: 1731 
  • Activity Level – Sedentary: 1.2 Multiplier
  • Add Calorie Multiplier: 25%

TDEE: 1731 * 1.2 = 2077 kcal

25% Caloric Surplus: 2077 * (1 + .25) = 2597 kcal