What does having a fast or slow metabolism actually mean, and how many calories do you burn in a day even if you don’t exercise? Can you actually improve your metabolism? There are many diets or supplements that promise to “boost your metabolism,” but to understand the problem with those fad diets it’s important to understand how your metabolism works. Your resting metabolic rate (or the similar basal metabolic rate) shows you how many calories you burn in a day. Knowing this number will help you if you’re trying to lose weight or stay healthy through walking.
Your resting metabolic rate (RMR) determines how many calories you burn when you’re not exercising. Combine this with the calories you burn walking, and healthier choices, and you can reach your fitness goals! Here’s what you need to know about your RMR and how you can use it to lose weight.
What Is Metabolism?
At a basic level, life is all about taking in substances and turning them into energy to produce, maintain, and destroy other substances in the body. The term metabolism is what we call all the chemical and physical processes involved in doing that. It can be broken down into two components: anabolism is where parts of the body are built and maintained, and catabolism is where bigger molecules are torn into smaller parts for energy.
Well, that’s what the dictionary says. When people talk about metabolism, they generally are referring to how fast someone burns calories, which is to say how fast your body turns food into energy and then uses it. An important thing to remember is that your body uses calories just to keep your heart pumping and your lungs working. Everything else, from walking 10,000 steps to doing dishes, burns even more calories on top of that minimum amount. How much you need to do the minimum is called the Resting Metabolic Rate.
What You Need To Know About Your Resting Metabolic Rate
Your resting metabolic rate is the minimum amount of energy expended in calories when all you’re doing is breathing, maintaining body heat, and pumping blood through your veins. There’s a related measure called basal metabolic rate, or BMR. Basal metabolic rate measures the estimated calories you burn through basic body functions. BMR and RMR are similar and often used interchangeably.
RMR varies from person to person, depending on their sex, muscle mass, weight, and age. Gyms will sometimes offer to find your resting metabolic rate, and there are labs that will figure it out for you. However, you can determine a pretty good estimate for yourself by applying the Harris-Benedict Equation, which is a formula created by Francis Benedict and James Harris back in 1919. It was updated in 1984 to the formula you see here.
The math is pretty simple.
88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)= RMR/BMR
447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)= RMR/BMR
Need a second opinion?
Another update to the Harris-Benedict Equation was proposed in 1990 by Mifflin and St. Jeor:
(10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5 = RMR/BMR
(10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161 = RMR/BMR
What about other activity?
Online calculators will use this equation to determine your resting rate and then add it to any additional exercise you do. You could theoretically do this yourself by adding back all of the activity you do (which includes more than steps). If your BMR is 1,750 and then you go for a 1-hour walk that burns 325 calories (and did no other activity during the day), you’d be burning 2,075 calories. In reality, just going about your daily life will burn more calories than that one particular walk.
While you can use Pacer to track your steps, there are a lot of other small things that you do that can’t be counted so easily. Standing in place doing dishes, for instance, does burn some calories. A recent study found that this kind of light activity is often undercounted, but is effective in reducing health risks including your risk of death! Light stretching also burns calories which are difficult to track, while step tracking may not account for activities like walking stairs or playing basketball. There’s another way to estimate your total calories burned…
Use multipliers as a shortcut
Even the most sedentary or injured people do some activity during the day. You can estimate your actual Total Daily Calories Expended (TDEE) by multiplying your RMR by a number corresponding to your activity level. Pacer Coach’s weight loss model (see our upcoming blog post) does this automatically based on your step count.
- Sedentary: RMR × 1.2
- Lightly Active: RMR × 1.375
- Moderately Active: RMR × 1.55
- Very Active: RMR × 1.725
- Extremely Active: RMR × 1.9
Moderately activity means doing moderate exercise 3 to 5 times per week. Very active increases this to hard exercise as many as 7 days per week.
If you’re not sure where your activity lies, you should probably tend to use a lower multiplier just in case. It’s easy to overestimate our activity and therefore overestimate our calories burned. That may feel great, but it can be counterproductive.
How Does Resting Metabolic Rate Differ Between People?
Is this number strictly accurate for everyone? The short answer is that it’s a useful guide, but your actual number may vary. The formula has been revised twice for accuracy, and it still doesn’t take your muscle mass into consideration. Muscle requires more energy than fat to maintain, so if you have a high muscle mass percentage (or low body fat percentage), your resting metabolic rate may be higher than shown. Due to other differences between individuals, some people simply have faster metabolisms than others (within reason – the difference is less than you might think).
Still, estimating your resting metabolic rate a pretty good way to figure out how much you should be eating.
How Can You Use This Info?
Though may supplements, articles or fad diets claim to be able to boost your metabolism, you can’t dramatically increase it without a lot of work. There isn’t any evidence that any substance can increase your metabolism by much, and most of the claims are baseless.
Minor metabolism boosts
There are some things that you can do to boost your metabolism, though they’re typically either temporary or only give a minor boost.
Interval training is a great way to boost your calorie burn and get more steps in a given time. It consists of alternating fast, intense exercise (like a fast walk) with slower resting periods (like a regular walking pace). Interval training causes you to consume more oxygen when training, which can boost your metabolism temporarily even after you finish your activity. Interval training workouts burn more calories than slow walks, which can help you with weight loss goals as well.
Build Muscle Mass
Strength training has many benefits, and one of them is that it increases your muscle mass. Maintaining muscle tissue burns more calories than maintaining fat tissue. This means that getting stronger can also boost your basal metabolic rate. You should be realistic, however. Most people don’t build up enough muscle to make a big impact on their metabolism. You can still make small gains, according to MedlinePlus.gov. Getting stronger can help you in your daily life, and can also help prevent injuries during your walks.
Other Things to Try
If you can’t increase your metabolism, you can still burn more calories an eat a bit less and achieve the same effect.
Watch what you eat
If you eat slightly fewer calories than you burn off, your body has to burn existing energy stores (including fat) to make up the difference. Don’t cut back too fast, too quickly, however. You’ll feel bad, it’s a health risk, and there’s some evidence that your body can adjust by reducing your metabolism or making you feel more hungry (at least in the short run). In fact, going on a crash diet can mess with your body long after you go off it. Instead, make little swaps like swapping out soda for a zero-calorie option. It’s easier, you’ll feel better and you’ll be healthier too.
While certain activities (like building muscle) can slightly increase your metabolism, there’s no magic diet that will dramatically increase your metabolism with no work on your part. Use this info to help avoid fad diets, and choose healthier eating plans.
Increase Your General Activity Level
Anything you do on top of breathing, eating, and keeping your heart beating increases what your body has to burn. Housework, playing with your pet, taking the stairs, and fidgeting counts. Walking is a great way to get your cardio in – try to get at least 30 minutes per day, 5 days per week. While it may not be possible to melt off belly fat through a specific workout, by walking more over time you’ll make gradual progress towards your goal.
Add Aerobic Exercise
The most efficient way to increase how many calories you use is to increase how much oxygen-consuming exercise you perform. Even 30 extra minutes of walking can add quite a bit to your energy needs. There are a lot of other great, low-impact activities that are really fun that you can try as well. You can find free resources on yoga, pilates, tai chi and more online, or find a class in your area. Ideally, you’ll want to take a class or two with an expert to make sure you’re doing things correctly, and make sure that you’re staying safe and avoiding injury. If all else fails, even standing or doing housework burns more calories than sitting on the couch.
Understanding your metabolism is an important part of maintaining a healthy weight and staying in good condition. Now that you have the basics, you’re are well on your way to mastering your own resting metabolic rate.
If you haven’t downloaded the Pacer app yet, download Pacer for free (on mobile)! You can also check out our website (mobile or desktop) or follow our blog for more great walking and healthy lifestyle tips.