When it comes to losing weight, gaining muscle, or even maintaining your current weight knowledge is power. For you to successfully achieve your goals in this matter, you have to properly understand all the factors that influence it. On the topic of weight, BMR and TDEE are two topics that come up every now and then, with experts claiming that understanding either (or even both of them) will help you achieve your weight goals better. In this article, we shall be covering the meaning behind BMR and TDEE, how to calculate them, and above all, answer the age-old question that is, “What is the difference between TDEE and BMR?”.
What Is BMR?
Also known as your Basal Metabolic Rate, BMR is the total number of calories that your body needs to perform basic, life-sustaining functions. Such functions include things like blood and oxygen circulation, breathing, cell production, nutrient processing, protein synthesis, etc.
Resting Metabolic Rate And Basal Metabolic Rate: Are They One And The Same?
According to Healthline.com, BMR and RMR are often used interchangeably, and many people think that they are one and the same. While this is true, and the two are quite similar, there is still a slight difference in these two metabolic rates.
As we have seen above, the BMR meaning relates to calories your body needs daily to help it perform basic functions to sustain your life. On the other hand, RMR (Resting Metabolic Rate) is the number of calories that your body burns at rest. Your resting metabolic rate is usually used to help calculate your basal metabolic rate.
Verywellfit.com further states that another difference between the two is that the most accurate measure of your BMR is one that is done in a lab setting under very restrictive conditions. Meanwhile, RMR is often measured in the morning, after a full night of restful sleep, before either eating or exercising.
BMR is at its lowest when you are sleeping and increases a little every time you eat to digest that food. This metabolic rate also increases if you have a high percentage of lean mass, such as muscle. Since muscle is more active than fat, a muscular person will be able to eat more because they have a higher metabolism.
Read More: Ideal Body Weight Calculator: When Should You Knock Off Those Unwanted Fats?
Is BMR Truly Important Concerning Weight-Related Matters?
Yes, it is. Individually, knowing your basal metabolic rate helps you determine how many calories you should consume to lose weight, maintain it, and gain some muscle- a fact that has been supported by several studies (4, 3). But this is not all that it is good for. According to a study published online in 2013, on a global scientific scale, understanding the basal metabolic rate helps with (1):
- Developing dynamic prediction models of weight gain and loss.
- Identifying patients with potential metabolic abnormalities.
- Informing the design of public health programs promoting obesity prevention in diverse populations.
- Assessing potential energy deficits in metabolically stressed patients, such as burn victims.
How To Calculate Your BMR?
If you are wondering, “what is my BMR?”. The best and most accurate answer will only come from a test done in a lab. However, because such tests are often quite expensive, most dieters and others looking to lose weight cannot afford to get one at the drop of a hat. This is where a basal metabolic rate formula comes in handy. Such a formula can easily find out your BMR at the comfort of your home without spending an inordinate amount of money.
With that being said, it is important to note that there are multiple BMR formulas available today. In fact, according to a 2013 study, there are about 248 BMR estimation equations that have been developed using diverse ranges of age, gender, race, fat-free mass, fat mass, height, waist-to-hip ratio, body mass index, and weight (1).
Of these 248 formula variations, the most commonly used ones in clinical practice are by Harris-Benedict, Mifflin-St Jeor, Owen, and World Health Organization. These formulas are said to give the most reliable predictions of BMR.
BMR Formulas
This equation uses your age, gender, height, and current weight to determine your basal metabolic rate.
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Revised Harris-Benedict Equation
This equation uses your age, gender, height, and current weight to determine your basal metabolic rate.
BMR Calculation For Men = 88.4 + (13.4 x weight in kg) + (4.8 x height in cm) – (5.68 x age in years)
Example: Here is the BMR of a 5 feet 10 inches, 35-year-old man who weighs 88 kilograms:
88.4 + (13.4 × 88kg) + (4.8 × 177.8cm) – (5.68 × 35years)
= 1922.24
BMR Calculation For Women = 447.6 + (9.25 x weight in kg) + (3.10 x height in cm) – (4.33 x age in years)
Example: To calculate the BMR for a 5 feet 5in, 32-year-old woman who weighs 60 kilograms:
447.6 + (9.25 × 60) + (3.10 × 165) – (4.33 × 32)
= 1375.54
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Mifflin-St Jeor Formula
According to Medicalnewstoday.com, while the Harris-Benedict equation might be more popular than the Mifflin Jeor formula, the latter is actually considered to be more accurate than the former.
Mifflin-St Jeor Formula For Men = (9.99 x weight in kg) + (6.25 x height in centimeters) – (4.92 x age) + 5
Example: Basal metabolic rate for a 29-year-old, 6 foot man who weighs about 70 kilograms:
(9.99 × 70) + (6.25 × 182.88) – (4.92 × 29) + 5
= 1704.62
Mifflin-St Jeor Formula For Women = (9.99 x weight in kilograms) + (6.25 x height in centimeters) – (4.92 x age) – 161
(9.99 × 80) + (6.25 × 152.4) – (4.92 × 28) – 161
= 1452.94
What Is TDEE?
TDEE stands for total daily energy expenditure, which is the full amount of calories that you burn each day. This includes not only calories spent while at rest but also calories burned by the body’s basic, life-sustaining functions, and calories burned through daily activities and physical exercise.
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How Does TDEE Affect Your Weight?
As seen above, TDEE basically refers to how much energy you expend in a day, which is your total daily energy expenditure.
This expenditure varies not only from person to person, depending on body size, sex, body composition, genetics, and activity level, but it can also vary from day to day in the same person.
What does this mean exactly? Imagine that on:
- Monday. You woke up, did some yoga, went on a hike, came back home, worked for a couple of hours, then later in the evening walked around your neighborhood with your dog.
- Tuesday. You had no time to work out and spent the whole day at your desk working and attending meetings.
- Wednesday. You did some light 20 minutes of cardio in the morning, then spent your day working at your desk.
- Thursday. You spent half the day at your desk; the other half at the beach running around with your dog and some friends.
In the example above, even if the person above eats the same thing on these four days, the amount of physical exercise/activity that they took part in will affect their total daily energy expenditure. For example, the amount of energy spent on Monday will highly differ from Tuesday or even Thursday.
So how does this affect weight, especially weight loss?
The energy that your body expends on a daily comes from calories and thus:
- To lose weight. You must create a negative energy balance where you consume fewer calories than what your body requires.
- To gain weight. You should create a positive energy balance, which is done by consuming more food than you need, i.e., giving it more fuel than it needs.
- To successfully maintain your current weight. The number of calories you consume must equate to the amount of food energy you expend daily.
In light of this, it is quite easy to see how your total daily energy expenditure directly affects how much you weigh and even how some simple changes can help you lose, gain, or even maintain weight. According to bodybuilding.com, understanding TDEE will help you lose weight by helping you achieve a calorie deficit. Research also suggests consuming 80 to 90 percent of your total daily energy expenditure will help you lose weight (2). To gain weight, consuming about 500 calories more than your TDEE will help you achieve these goals.
Read More: TDEE Calculator: How Do You Keep Your Weight In Check?
How To Calculate TDEE?
If you are wondering, “what is my TDEE?” Here is how to go about it. As we stated before, BMR is used to calculate, estimate, and determine TDEE. As stated above, BMR (Basal Metabolic Rate) is the total number of calories your body requires for normal bodily functions like keeping your heart beating, inhaling and exhaling air, digesting food, making new blood cells, maintaining your body temperature, and every other metabolic process in your body.
Once you have determined your BMR by any of the formulas given above, either the revised Harris-Benedict formula or the Mifflin-St Jeor method. In short, the TDEE formula is multiplying your BMR by your activity level. Since activity levels differ from person to person, here is how you can use the TDEE formula to figure out your total daily energy expenditure:
- Sedentary lifestyle (little or no exercise, desk job) = BMR x 1.2
- Lightly active (light exercise/sports 1-3 days/week) = BMR x 1.375
- Moderately active (moderate exercise/sports 6-7 days/week) = BMR x 1.55
- Very active (hard exercise every day, or exercising 2x/day) = BMR x 1.725
- Extra active (hard exercise 2 or more times per day, training for a marathon, triathlon, etc.) = BMR x 1.9
If you do not want to manually calculate TDEE, you can try using an online calculator to help you determine this. Online calculators for this usually use the person’s weight, height, workout routine, and gender. Not only do these calculators help determine TDEE, but they also show your body mass index (BMI), basal metabolic rate (BMR), macronutrients, and other details.
What Is The Difference Between BMR And TDEE?
Here are the main differences between basal metabolic rate and total daily energy expenditure:
- TDEE Varies On A Daily Basis. It includes activity level, and we don’t usually do the same activities using the same amount of energy every day; your energy expenditure will vary. On the other hand, your basal metabolic rate remains the same. Your body does the same life-sustaining functions every day; whether you work out or not, it remains the same.
- Amount Of Energy Used. Another difference between BMR and TDEE is that the latter refers to all the energy used by the body, which is BMR plus physical activity level. On the other hand, BMR only refers to the energy that your body uses to help keep you alive and functioning daily.
Basically, TDEE factors in daily activities and exercise while BMR does not.
The Bottom Line
When it comes to the difference between BMR and TDEE, the main differentiating factor is that the latter, unlike the former, includes how much physical activity a person does in a day. While the latter does not and is only concerned with the energy used to keep you alive and your body functioning normally.
The other slight and often overlooked difference is that TDEE will vary daily depending on how much you exercise – if at all. Please note that while manual calculations can help you estimate these two things, getting them done by a professional or even at a lab is more accurate. For things like weight management and related planning, a calculated estimate is perfectly fine and can be useful.
DISCLAIMER:
This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. A licensed physician should be consulted for the diagnosis and treatment of any medical conditions. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!
SOURCES:
- Best Fitting Prediction Equations for Basal Metabolic Rate: Informing Obesity Interventions in Diverse Populations (2013, ncbi.nlm.nih.gov)
- Body composition and power performance improved after weight reduction in male athletes without hampering hormonal balance (2015, pubmed.ncbi.nlm.nih.gov)
- Energy expenditure and requirements in aging humans (1992, pubmed.ncbi.nlm.nih.gov)
- Modeling the dynamics of human energy regulation and its implications for obesity treatment (2002, onlinelibrary.wiley.com)
