How fast is your metabolism? Many people don’t know the exact answer to that question. They may have a good idea of whether or not their metabolic rate is slow or fast, depending on their ability to gain or lose weight, but the actual numeric rate is something else entirely.
How can you determine what that number is? What do you need to know about your metabolic rate to use to your advantage when trying to become healthier?
Our experts answer both of those questions and more here.
What Is Your Metabolism?
You’ve probably heard the word “metabolism” before and had a good general idea of what it is. However, to understand the differences between aerobic and anaerobic metabolisms, it’s a good idea to have a solid grasp of the concept of metabolism in general.
When you’re at rest, your body is still burning calories. This makes sense because your digestive system is still doing its thing; the cells in your body are consuming energy as you breathe, your heart beats, and your nervous system remains functioning, even when you’re asleep.
To fuel all those actions and meet your calorie needs, you need to consume foods that are digested even when you’re at rest. This provides what your body needs to keep going. Your metabolism is just that: the amount of calories and energy your body burns while it’s running.
Your resting metabolic rate (RMR) is measured as the energy your body needs even while you’re sleeping, sitting in front of the television, and resting outside reading a book, among other things. Most people have a metabolism that burns some calories while their bodies are going about their normal states of business, but too often, you eat more calories than your body needs, so you’ll start to gain weight.
What Affects Your Metabolism?
There’s more than one thing that affects your metabolism. It doesn’t come down to a single factor or even two or three. All of these things play a role in the general speed of your metabolism:
Your Muscle Mass
Muscles burn more calories than body fat due to their overall makeup. If you have plenty of lean muscle mass, you’ll have a higher metabolism than you would if you didn’t hit the gym. This is why it is important to build muscle through strength training.
The younger you are, the faster your metabolism is. Typically those who are under the age of 30 have a pretty metabolism. However, once you hit that age (30, of course), your metabolism begins slowing down and continues to do so as the years go by.
Your Weight and Height
In addition to your age, your overall height and body weight affect your metabolism. After all, this measures how many daily calories your body burns while it’s at rest, so someone who weighs more, even if they’re less active, will have a slightly higher metabolism.
The same is true for your height. Taller people have quicker metabolisms because their circulatory systems need to move more to function.
When gaining lean muscle mass, men tend to win out over women. They have no issues gaining those muscles quickly and easily and tend to lose weight faster.
This is because men tend to have faster metabolisms than women. Thankfully, women have some control over their metabolisms, and things like eating the right foods and exercising can help.
If anyone in your immediate family had a fast metabolism, you might as well. One of the things that you can’t control (your genetics) plays a part in your overall metabolism. This can be either good or bad, depending on the overall metabolic rate of your close loved ones.
Two main hormones can play a role in how fast your metabolism moves. The first is your estrogen levels. Women have metabolisms that tend to slow down once they get near or enter menopause because their estrogen levels drop.
The second is your thyroid. If you have any issues with your thyroid — either it makes too much of the thyroid hormones or too little — your metabolism will either speed up or slow down.
Your Activity Levels
How active are you? People who head to the gym regularly or exercise outdoors practically every day have a faster metabolism than those who are more sedentary.
The very act of physical activity can speed up your metabolism quite a bit. On the other hand, if you spend a lot of your time relaxing or sitting, your metabolism will be slower.
Calculating Your Metabolic Rate
Understanding what affects your metabolism is just the first step. The next involves calculating that metabolic rate. To do this, you’ll need a few different measurements, a calculator, and some equations. Ready to get started? No need for a BMR calculator here!
What You Need for Calculations
To determine your metabolic rate, you first need several important measurements. These are:
- Your Weight in Pounds
- Your Height in Inches
From there, you’ll do a few quick mathematical equations, turning those numbers into your weight in kilograms and your height in centimeters.
Those equations are:
Your weight in pounds / (divided by) 2.2. This gives you your weight in kilograms.
Your height in inches X (multiplied by) 2.54. This gives you your height in centimeters.
Write down those two numbers because you’ll need them for the next steps.
Determining Your Metabolic Rate
Two equations are used to determine your metabolic rate, which is the number of calories your body consumes (or burns up) when you’re resting. There’s one set of mathematical equations for women and one for men.
For Men: BMR = (10 x your weight listed in kilograms) + (6.25 x your height listed in centimeters) – (5 x age in years) + 5 = calories
For Women: BMR = (10 x your weight listed in kilograms) + (6.25 x your height listed in centimeters) – (5 x age in years) – 161 = calories
Note that the number you end up with isn’t the total calories you should eat daily. Instead, it measures how many you should start with because your body needs extra daily calories to survive and perform basic functions. (And remember that some are burned off in other ways via the thermic effect of food and other things.)
Taking the Next Steps
Once you know your BMR or basal metabolic rate, you need to determine your daily expenditure. This requires you to take a look at how active you are on a regular basis.
There are four levels of activity:
- Sedentary – People in this category spend most of their days sitting down. They might do some light cleaning or walk a little, but that’s it.
- Low Active – If you spend around half an hour or 45 minutes of your walking or jogging at a slow pace, on top of everything you do at the sedentary level, then you’re in the low active category.
- Active – Do you tackle a number of different daily activities at a moderate level (raised heart rate) every day? Things that fit this active category include vigorously cleaning for an hour or exercising for at least 60 minutes or more each day.
- Very Active – Finally, there are the people who are super active. If you spend a good portion of your day on your feet and do some vigorous workouts, you’re considered to be very active.
Calculating Your Total Daily Energy Expenditure
Are you ready for more math? It’s time to take your BMR (basal metabolic rate) and apply it to your activity levels.
- Sedentary – For both men and women, you take your BMR and multiply it by 1.00
- Low Active – For women, this number is your BMR times 1.12. For men, it’s BMR times 1.11
- Active – For men, take your BMR and multiply it by 1.25. Women, multiply your BMR by 1.27
- Very Active – Women, obtain your number by taking your BMR and multiplying it by 1.45. Men, it’s your BMR times 1.48
The number that you end up with is your TDEE or total daily energy expenditure.
What Does Your Metabolic Rate Tell You?
Knowing your metabolic rate and your TDEE will help you determine how much you should eat daily. If you want to lose weight, eat healthy foods, keep your calories lower than your TDEE (calorie deficit), or start an exercise routine (adjusting your TDEE as needed.) Healthy weight loss really is that simple!
Have questions about this or anything else? Contact us!
Your No-Nonsense Guide to Metabolism | UNC Health Talk
How to Calculate Your Metabolism, According to a Dietitian | Eating Well