In part one, we looked at what makes up most of your daily caloric need: your basal metabolic rate (the energy cost of maintaining life) plus the calories you burn through movement.
Now we’re going to see how you can actually increase your basal metabolic rate by gaining metabolically active lean tissue: in a word, muscle.
The magic of muscle
Building muscle means reversing the decline in metabolism that takes place in sedentary people as they get older. It means creating a body that is more resistant to gaining fat.
But maybe when I talk about building muscle, you envision sprouting a bulky, manly physique as soon as you pick up the weights.
Not gonna happen.
Please believe me when I say that the vast majority of women who want to grow large muscles find it a very challenging, difficult task. If you’re not taking anabolic steroids or human growth hormone, you have nothing to fear from barbells, dumbbells, and weight machines.
The she-hulks you’ve seen in women’s bodybuilding competitions have created their physiques with a little (or a lot of) help from banned substances.
You probably don’t want to be a female Arnold, but I know you want a flat stomach, a curvy butt, firm legs, and shapely shoulders. They’re made out of muscle.
And even if you’re not motivated by vanity, you still want more muscle because it
- burns more calories than fat
- preserves function and independent living as you age
- increases bone density through the force muscles apply to bones during strength training
- improves posture and balance
- enhances confidence
- and, frankly, makes you feel great in your own skin.
Did I mention that I think strength training is the closest thing we have to a fountain of youth?
I could show you an enormous stack of studies proving that 1. strength training has amazing health benefits and 2. people of all ages (including the very elderly) can do it and enjoy measurable improvement.
But for now I want to show you some hard numbers that reveal the metabolic payoff of building muscle.
A tale of two sisters
Let’s compare 45-year-old identical twins, Karen and Margaret. They’re genetically the same, so we know life dealt them the same metabolic hand.
They’re 5’ 6” tall. Karen weighs 150 pounds, and Margaret weighs 140.
Karen is sedentary and has a bodyfat level of 35 percent. If we multiply her bodyfat percentage by her total weight (.35 x 150), we can determine that she’s carrying 52.5 pounds of fat.
If we subtract the fat from her total weight, we can see that she has a lean body mass (organs, skeleton, muscles, skin, water) of 97.5 pounds (150 – 52.5).
Margaret, in contrast, is very active. She bicycles and also trains with weights. She weighs 10 pounds less than Karen but is more than 10 pounds leaner.
How? Her bodyfat percentage is 22. Multiply that by her total weight (.22 x 140), and we see that her body composition includes about 31 pounds of fat. Thus, she has 109 pounds of lean mass (140 – 31). And she has 21.5 fewer pounds of fat than Karen.
There are lots of ways to figure out your bodyfat percentage, but one of the easiest is to plug a few measurements into the calculator on this website: primefit.org/estimate-your-bodyfat/. Tracking your bodyfat every week or so is much more helpful than stepping on a scale. Only the bodyfat measurement can tell you whether you’re maintaining, gaining, or losing lean muscle.
Now that we know both Karen’s and Margaret’s lean body mass (LBM), we can calculate their basal metabolic rate (BMR) and then their total daily energy expenditure (TDEE).
We’re going to use the Katch-McArdle formula for our calculations because it takes LBM into account and will highlight the metabolic difference between the sisters.
(You can find the complete formula in my free fat-loss report. To receive a copy, just sign up for my e-mail list. Or, if you wish to use another formula that does not consider LBM, use the calorie calculator here on the site.)
I’ve run the numbers, and Karen’s BMR is 1,327.
Margaret’s is 1,442.
Remember that BMR reflects only the energy cost of existing each day. So even if both women slept around the clock, Margaret would burn 115 calories more than Karen—even though Margaret weighs less.
We haven’t even looked at the energy cost of their daily activities.
Let’s do that now. Once you know your BMR, using either of the formulas I’ve just mentioned, you can multiply it by an “activity factor” for a good estimate of TDEE:
- Sedentary—person doesn’t exercise: multiply BMR by 1.2
- Lightly active—person does light activity or sports one to three times weekly: multiply BMR by 1.375
- Moderately active—person does moderate activity or sports three to five days a week: multiply BMR by 1.55
- Very active—person does hard exercise or sports six or seven days a week: multiply BMR by 1.725
- Extremely active—person trains intensely more than once a day or performs a job that is very physical: multiply BMR by 1.9
Karen should use 1.2 because she’s sedentary—so her TDEE is 1,592 (BMR of 1,327 x 1.2). That’s the number of calories she needs to maintain her weight. And it isn’t all that many.
Margaret should use 1.55, the multiplier for a person who is moderately active. Her TDEE is—are you ready for this?—2,235 (BMR of 1,442 x 1.55). She can consume 643 calories more every single day than her sister and maintain her weight.
Her greater lean body mass gives her the “right” to eat 115 more calories each day, and her active lifestyle increases the advantage by 500+ additional calories.
So does Karen have a slower metabolism? Absolutely. But she isn’t doomed.
If she gets sick and tired of it, she can start training with weights to increase her lean body mass. She can add some regular cardio sessions to torch still more calories.
Yes, it’ll take time for her to grow her muscle mass through strength training. But at the same time she’ll be improving her bone density, her balance, and her mental health. Oh—and she’ll be catching up with her sexy sister.
A note about individual variation
The formulas used to determine BMR and TDEE are accurate for most people. But some people were born with a metabolic rate that’s faster or slower than average, and the variability can range from 10 to 30 percent.
It isn’t fair, but that’s life.
Is the person with the lower energy requirement doomed to obesity? Of course not. But she does have a lot less wiggle room in her diet.
The best things she can do to even the odds are to increase her muscle mass and add as much activity to her life as possible, through both exercise and non-exercise activity thermogenesis (NEAT), described in part one of this article. With NEAT—standing, walking, and simply changing posture more often—she can burn another 200+ calories a day.
Protecting lean body mass
We’ve looked at how adding muscle and increasing activity can ramp up your metabolism.
Now I want to offer some tips for protecting your hard-won muscle.
Three of the greatest dangers to your lean tissue are
- sedentary lifestyle
- overly restrictive dieting and
- lengthy workouts.
In part one of this article I talked about the gradual loss of muscle that takes place each decade in people who are inactive. It’s that relentless gradual loss that turns a vigorous 50-year-old into a frail 82-year-old who can’t rise from a chair without assistance.
And as I hinted earlier in this installment, it’s never too late to gain strength. Researchers are working with people in their 70s, 80s, and 90s, and all of them make significant gains with regular resistance training.
The dangers of dieting
One of my biggest pet peeves: people think they want to lose weight. .
No, they don't.
They want to lose fat.
They step on the scale and see that they weigh five pounds less than two weeks ago—and they think it’s a victory.
But if they lost three pounds of muscle and two pounds of fat, it’s actually a miserable failure. For every ounce of muscle lost, their metabolic rate goes down.
I want you to understand that safe dieting means muscle-sparing dieting. And that the number that really matters is bodyfat percentage, not scale weight. If your bodyfat is going down, you’re getting leaner, your clothes will fit better, and you’ll look better, even if the scale doesn’t budge.
So how do you diet safely and avoid starvation mode? The keys are
- moderate, not severe caloric restriction (cutting 10 to 20 percent of calories is a good place to start—see my free fat-loss report for a full explanation)
- adequate consumption of protein and
- strength-training exercise at least twice a week.
Oh, and “moderate caloric restriction” absolutely does not include fasting. If you’re under a doctor’s care and on a medically supervised fast, that’s one thing. For everybody else fasting is dangerous and counterproductive.
How much protein is adequate? The American Dietetic Association says that people who do resistance training need .54 to .77 grams per pound of body weight. I think this is a little low. The National Strength and Conditioning Association’s (NSCA) Essentials of Strength Training and Conditioning notes that “when caloric intake goes down, protein requirement goes up.” So dieters need more per pound than non-dieters.
NSCA further indicates that people involved in athletic activities need more protein. It recommends an intake of .68 to .9 grams of protein daily per pound of bodyweight. This is closer to the old bodybuilder rule of 1 gram per pound and, I think, safer.
(Added benefit: Did you know that you actually burn calories digesting food—and that you burn more calories breaking down protein than carbs or fats?)
The combination of regular strength training and plenty of protein will help prevent your body from consuming its own muscle tissue when you’re dieting.
Above I mentioned that lengthy workouts could endanger your muscle. That’s because in training that lasts more 90 minutes, your body begins to use protein (that is, your muscles) as an energy source.
After 90 minutes, from 3 to 18 percent of the fuel you burn is likely to be amino acids—protein liberated from your muscles. When you’re dieting the risk is greater.
So work out hard in the gym, but keep your sessions brief and intense. Unless you’re training for a competition, there’s no reason not to get in and get out in an hour.
More on protein
For more information on the benefits of protein, check out these posts:
Want more?
I hope this two-part series has helped you understand your metabolism and how you can enhance it.
I’d love to hear your comments and questions. Please contact me through the comment box.
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{ 4 comments… read them below or add one }
Xllnt! I really love the detailed examples with the twin sisters it is so much more clear to me how effective muscle mass is. Simply amazing. I'd read about it of course but your description really solidified how important it really is.
thanks so much! I'm glad it was helpful.
M
THANK YOU for your note that women WON'T get big without steroids! People who see me lifting heavy weights ask if I am scared of getting big, and my standard response is "no, I'm not on the 'roids." Nobody seems to get it. Strength is sexy!
I know. It\’s amazing. You\’d think that fear would have died out 20 years ago. But it never changes. My first exposure to weights, in college at age 19 (and this was late 1970s), was a strength-training class. I\’ll never forget the really good-looking cheerleader who was in the class and dropped out because she was afraid of \”getting big.\” Weights are the best!
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