Have you ever heard of the term “basal metabolic rate”? Do you know what it is and why it’s extremely important to know your numbers? Do you know what to do to make your BMR numbers work for you regardless of whether your goals are to lose weight (body fat) or gain weight (lean muscle) and do it in a safe and effective way?
Your BMR (Basal Metabolic Rate) is defined as the minimum number of calories your body burns whether at rest, working out or lying down. This means that everyone has a set number of calories that they need in order to stay alive and it’s as different for you as it is for your children, friends, parents or even siblings. These calories are the absolute minimum amount of energy your body burns, and includes all involuntary (independent of your own will) activities that your body does to stay alive such as digestion, respiration, circulation, removing waste products and regulating body temperature.
Factors that affect your BMR include age, genetics, weight, heredity, body fat percentage and gender. For example, your BMR is the number of calories your body would need to spend 24 hours asleep in bed. Your BMR number will depend on many factors such as your weight, your diet and your current activity level.
The BMR includes the number of calories used for activities from breathing, maintaining your body temperature, your heart pumping, to your brain working at various levels and other functions that occur in the body while asleep. The calories you burn when awake, moving (including exercising) are not included in the BMR. Think of your BMR as the number of calories needed to stay alive if you were bedridden.
Your BMR slows down at roughly 2% every 10 years after the age of 20. This is why many people can’t understand why they gain weight as they get older, but they still have the lifestyle (or eat) the same way they did in their 20’s, 30’s and even 40’s. They need to reset their BMR to reflect the changes that are taking place in their bodies!
Women will naturally have a lower BMR than men, as men usually have a lower percentage of body fat and a higher percentage of muscle. Of course this does not included female bodybuilders as their body fat is kept below the essential body fat amount (10-12%). By having a lower body fat percentage and a higher percentage of lean muscle mass, men require a higher metabolism to maintain that muscle.
Also, women that are leaner (those having body fat percentages between 15-25%, as well as those who are physically active in weight lifting and strength training (2-4 days a week) will also have a higher BMR than women who are more sedentary, have a higher level of body fat, and/or are overweight.
Your BMR also increases with your body weight, in both males and females, so the heavier you are (weight) the higher your BMR is. At the same time, your BMR decreases with age, due to the decrease in lean body mass that often occurs in older adults. Again, keep in mind the fact we noted earlier that there is about a 2-3% drop in your BMR every decade after the age of 20.
Did you know that your external temperature can also be responsible for raising BMR? If the weather is cold, the body must create more heat to keep warm. Anything that affects body temperature and tries to raise or lower it will cause the BMR to increase in order to counteract this effect.
Why It’s Important To Know Your BMR
Whether your goal is to lose weight (body fat), gain weight (lean muscle), or to just maintain your current weight, knowing your BMR can help you attain and maintain your goals. If like so many Americans who are eating right, exercising and living a healthy lifestyle, but still can’t seem to shed those extra pounds, knowing your BMR could be the missing link to your weight and health goals. To figure out your BMR the long way you’ll need to use the following formula:
Calculate Basal Metabolic Rate for Women
Women: 655 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
Example 1: You are a 38-year-old woman, who is 5’4″ and 142 pounds. First, convert your height into inches. 5’4″ equals 64 inches. Now include your values into the equation above.
- 655 + (4.35 x 142) + (4.7 x 64) – (4.7 x 38)
- 655 + 617.7 + 300.8 – 178.6 = 1394.9
- Your BMR = 1394.9
Example 2: You are a 28-year-old woman, who is 5’7″ and 172 pounds. First, convert your height into inches. 5’4″ equals 64 inches. Now include your values into the equation above.
- 655 + (4.35 x 172) + (4.7 x 67) – (4.7 x 28)
- 655 + 748.2 + 314.9 – 131.6 = 1586.5
- Your BMR = 1586.5
*Note: you can see that the younger (28 years old) woman’s BMR’s higher than the older (38 years old) woman’s BMR due to her height, weight and age.
Calculate Basal Metabolic Rate for Men
Men: 66 + (6.23 x weight in pounds) + (12.7 x height in inches) – (6.8 x age in years)
Example 1: You are a 40-year-old man, who is 5’9″ and 175 pounds. First, convert your height into inches. 5’4″ equals 69 inches. Now input your values into the equation above.
- 66 + (6.23 x 175) + (12.7 x 69) – (6.8 x 40)
- 66 + 1090.3 + 876.3 – 272 = 1694.6
- Your BMR = 1694.6
Example 2: You are a 30-year-old man, who is 5’9′ and 220 pounds. Now input your values into the equation above.
- 66 + (6.23 x 220) + (12.7 x 69) – (6.8 x 30)
- 66 + 1370.6 + 876.3 – 204 = 2108.9
- Your BMR = 2108.9
*Note: you can see that the younger (30 years old) male’s BMR’s higher than the older (40 years old) male’s BMR due to his height, weight and age.
Okay, now that you know your BMR, you’ll need to calculate your activity level. Keep in mind the more active you are, the more calories your body burns on a daily basis. After you’ve entered your activity level (choices range from light to heavy) you’ll have the amount of calories you must consume daily to stay at your current weight.
Calculate Total Calorie Needs
Did you know that even the most inactive individual will burn additional calories over their BMR by just doing normal bodily functions like laughing and smiling? For a much better understanding of how many calories your body uses each day, you need to add your activity level into the overall equation. To find out your total daily calorie needs or TDEE (total daily energy expenditure), just multiply your BMR by the activity factor that is appropriate for your lifestyle as indicated below:
- Sedentary (little or no exercise): BMR x 1.2
- Lightly active (easy exercise/sports 1-3 days/week): BMR x 1.375
- Moderately active (moderate exercise/sports 3-5 days/week): BMR x 1.55
- Very active (hard exercise/sports 6-7 days a week): BMR x 1.725
- Extremely active (very hard exercise/sports and physical job): BMR x 1.9
With the example above, let’s presume you are only lightly active. All you need to do is multiply your basal metabolic rate from above (1394.9) by 1.375 to get the total of 1,917.98 calories. This equals the total number of calories you would need to consume in order to maintain your current weight. If you are consuming more calories, you will gain weight, and if you’re consuming fewer calories, you will lose weight. The key in all this is again, is knowing your basal metabolic rate.
Tying It All Together!
We all know that in order to lose weight, you must consume fewer calories than your overall needs. Weight loss can and will occur when you burn more calories than you eat. To lose one pound a week, you’ll need to reduce your intake of calories by at least 500 calories a day.
You can also lose one pound a week by burning an extra 500 calories a day with exercise. For some, the combination of both diet and exercise works the best (burn 250 calories during exercise and decease caloric intake by 250 calories = 500 calories x 7 days = 3,500 or 1 pound). Keeping a journal handy to document your workouts as well as your caloric intake will help you stay on track with your fitness goals. If you’re not sure how many calories you’ve burned during your physical activity, estimate the amount and decrease that total by 100-200 calories.
When journaling for weight lost (now that you know your BMR) make sure that you write down everything you eat and drink each day. This will include the serving size amount, calories, fat, protein, fiber and carbohydrates that are contained in all of the foods and liquids that you consume. Documenting your water intake is also a great idea.
For weight gain, make sure that you’re eating clean carbs (i.e. lots of vegetables), and lean proteins so that you succeed in gaining nice lean muscle tissue not extra body fat.
Calculate Calories to Lose Weight
One pound, whether it’s body fat or lean muscle, is equivalent to 3,500 calories. This means that an individual must reduce that many calories from their food intake or burn those calories with exercise in order to lose a one pound a week. By creating a deficit of 500 calories a day, you will end up losing one pound a week. If your total daily calorie needs equal 1,917.98 to maintain your current weight, just decrease 500 from that, and you will have the amount of calories you can eat every day and still lose 1 pound each week. In this example, the total will be 1,418 calories per day.
Calculate Calories to Gain Weight
To gain one pound per week, you’ll need to increase your calories by 500 in your nutritional plan each day. If your daily caloric need is 1,917.98 to maintain your current weight, adding 500 to your overall calories will mean you can consume a total of 2,418 calories a day. Again, make sure those calories are coming from nutrient dense foods so that you’re eating clean and lean!
How to Improve Your Metabolism
So, what is the big deal with the metabolic rate and why is it so important? Your metabolism is the true indicator of your overall dieting and fitness success. You really need to keep your engine running hot in order to burn the most amount of calories each day. Unfortunately, there are lots of things that can slow it down. These include:
- Age: Your metabolism actually slows down by 5% every 10 years.
- Fat: Lean muscle tissue burns 3 times more calories than fat.
- Dieting: Drastically cutting calories shocks your body and sends it into starvation mode. It basically slows way down and runs cooler in order to maintain calories because it believes that there is a short supply of food available. When this happens, your weight loss progress hits a plateau.
Building lean muscle mass with weight training two to three days a week (minimum) can increase your metabolism which in turn can help you decrease unwanted body fat and help you get leaner. Remember, knowing your BMR and utilizing these important numbers, along with good nutrition and exercise will give you the body that you’ve been working so hard for!