Speed up your metabolism, part 2

by Mary C. Weaver, CSCS on June 1, 2012

Last week, in part one of this post, 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.

Many will envisage when I talk about building muscle a bulky, manly physique as soon as you pick up a set of 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 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 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 40-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 pounds of total body weight — 52.5 pounds of fat).

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.


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 this calculator.

Tracking your bodyfat every week or so is much more helpful than just 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).

I’m going to use what’s called the Katch-McArdle formula for our calculations because it takes LBM into account and will highlight the metabolic difference between the sisters.

(If you wish to use a formula that is pretty accurate for most people but does not consider LBM, try this calorie calculator.)

I’ve run the numbers, using the Katch-McArdle formula:

  • Karen’s BMR is 1,327, and
  • Margaret’s is 1,442.

Remember that basal metabolic rate 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, the number of calories you burn every day:

  • 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 cardio sessions to burn additional calories–as well as some interval training to torch even more.

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:

Dieting? Focus on protein

How much protein do you need?

Want more?

I hope this two-part series has helped you understand your metabolism and how you can enhance it. You can learn even more by joining me at 7 p.m. EDT Tuesday, June 19, for a free teleseminar. Check it out here.

I’d love to hear your comments and questions.


{ 23 comments… read them below or add one }

1 Suzan St Maur June 1, 2012 at 12:45 pm

That’s astounding, Mary. It all makes sense now. And thanks to you I can know speak “savvy” with my son who is a keen body-builder / weight training fan … Sadly I can’t exercise as much as I would like to due to medical issues, but at least I now know how to make the best of whatever exercising I CAN do. Thanks so much!


2 Mary C. Weaver, CSCS
Twitter: themusclediva
June 1, 2012 at 1:22 pm


Give yourself a pat on the back for whatever you can do. I came across a quote online the other day that said something like “no matter how slow you are, you’re lapping everybody who’s still sitting on the couch.”



3 Sarah Arrow
Twitter: saraharrow
June 1, 2012 at 1:21 pm

Awesome Mary, just awesome.
It all slots into place nicely – thank you. Muscle is amazing, especially when we use it correctly.


4 Mary C. Weaver, CSCS
Twitter: themusclediva
June 1, 2012 at 10:36 pm

Sarah–yes, indeed. Forget diamonds: muscle is a girl’s best friend. :-)


5 Leanne Chesser
Twitter: leannechesser
June 1, 2012 at 9:42 pm

Thank you for this wonderfully informative article! I knew the concepts in general, but now I have a much more thorough and detailed understanding . . . and some exact numbers.


6 Mary C. Weaver, CSCS
Twitter: themusclediva
June 1, 2012 at 10:35 pm

Leanne, thanks!


7 Margreet June 1, 2012 at 11:05 pm

Good to know!

I guess just eating spinach isn’t going to give me muscles :-) got to get to the gym to dip into the fountain of youth.

So is it better to lift weights than to do aerobics, or is any kind of fitness going to give me more muscles?


8 Mary C. Weaver, CSCS
Twitter: themusclediva
June 2, 2012 at 6:10 am

Hi, Margreet–

Thanks for commenting! Aerobic exercise has great health and fat-burning benefits, and weight-bearing aerobic work (e.g., running) can help prevent the loss of muscle. But it won’t build muscle.

For that, you need strength training–with machines, free weights, or body-weight moves (think pushups and body-weight squats).

Next, I think I need to write about how much strength training we need to get results. Good news: you can get fabulous benefits without spending a lot of time.


9 ije June 2, 2012 at 2:32 am

great article. i loved how you broke it down and used the example of the twins. that’s great motivation for getting out of bed every morning to work out. thanks for the inspiration:-)


10 Suzanne
Twitter: WorkoutNirvana
June 2, 2012 at 9:44 am

Besides very comprehensive explanations of how to figure out body fat and lean muscle mass, you share some valuable truths. There was never a more true statement than “the vast majority of women who want to grow large muscles find it a very challenging task.” Secondly, yes, a fast metabolism is something you can be born with and if you weren’t, having “less wiggle room” with diet is the perfect way to look at it. Agreed about the protein recommendation; there is much conflicting info out there and it gets confusing. I think your previous protein article explains it the best. Great work Mary!


11 Mary C. Weaver, CSCS
Twitter: themusclediva
June 2, 2012 at 12:19 pm

Thanks for the lovely comment. I appreciate it so much!


12 Te Ratahi
Twitter: saymonkeyphotos
June 2, 2012 at 12:22 pm

Great post! My husband encourages me to weight train with him for all the same reasons. It helped me lose 30kg in 8months after I had a 35kg pregnancy weight gain. Still have a little bit to go but I’m getting there!


13 Mary C. Weaver, CSCS
Twitter: themusclediva
June 3, 2012 at 1:16 pm

Excellent, Te! Glad to hear you’re getting such good results. :-)


14 Pamela Hernandez June 2, 2012 at 4:28 pm

Great point – losing weight and losing fat aren’t always the same thing. And it is hard to gain muscle! I keep trying and trying and it takes a lot of work!


15 Mary C. Weaver, CSCS
Twitter: themusclediva
June 2, 2012 at 4:32 pm

Pamela—I know . . . believe me, I know! I always want more.


16 Elaine Sturgess June 3, 2012 at 6:48 am

Fantastic post Mary. Can you tell me what you mean by “lengthy workouts”. What kind of length of time and balance between aerobic and strength traning would you recommend? Thanks!


17 Mary C. Weaver, CSCS
Twitter: themusclediva
June 3, 2012 at 1:15 pm

Hey, Elaine–thank you.

Some kinds of athletes (paid professionals, marathon runners, triathletes, etc.) can’t escape really long workouts. For everyone else, 90 continuous minutes should be the max. But we certainly don’t need to go that long to get the benefits of working out.

The standard recommendation these days from bodies like the American College of Sports Medicine looks like this: 150 minutes of cardio each week plus two resistance-training sessions (specific length of time not given because the object is not to lift for a certain number of minutes but to adequately work all the body’s muscles).

Beyond that, let your preferences be your guide. And I’ll make two observations:

1. Anything you do is better–far better–than nothing. So even if you got only 90 minutes of cardio total per week, you’d be getting most of the benefits of having done 150 minutes.

2. Anything that elevates your heart rate to, say, 65 percent or more of maximum heart rate can be considered cardio. You can get there by walking, running, taking an aerobics class, raking leaves, or even doing resistance training, provided you keep moving. Most of my strength training actually qualifies as cardio too because my heart rate stays elevated.

More info about heart rate here: http://primefit.org/heart-rate-upgrade/


18 jamie G. Dougherty June 3, 2012 at 4:04 pm

So many good points but my favorite…” One of my biggest pet peeves: people think they want to lose weight. No, they don’t. They want to lose fat.” Perfectly said.


19 Mary C. Weaver, CSCS
Twitter: themusclediva
June 3, 2012 at 9:24 pm

Jamie, thanks!


20 Linda Mattacks
Twitter: Linda_Mattacks
June 4, 2012 at 7:59 am

Question for you, Mary :-)

I’m taking up more space than I’d like to but am apparently well within the “norm”/ acceptable. So I played around with the bodyfat calculator you link to, changing various measurements and noticed that the alarm bells definitely started sounding when the waist measurement got bigger.

How much is that a real healthy/ unhealthy indicator and how closely should we watch and control that?


21 Mary C. Weaver, CSCS
Twitter: themusclediva
June 4, 2012 at 12:43 pm

Linda, really good question! Waist measurement is highly correlated with overall health. Why? Because abdominal (or visceral) fat is much more dangerous than fat that accumulates on hips and thighs, for example.

Of course, we can’t really control where fat is deposited. It’s a factor of gender, genetics, and hormonal balance. As women get older and become less estrogenic, they are more likely to deposit fat around the waist and back. Speaking as a midlife woman who has coped with “back fat,” I say yuck!

What we can do is work on 1. slowly reducing our level of body fat through healthy, moderate calorie restriction and exercise and 2. increasing our muscle mass through strength training. As the body-fat level drops, the abdominal fat will go down.

So–quick answer–if your waist measurement is increasing, yes, you should be concerned and start taking action.


22 Shira June 4, 2012 at 10:24 am

Mary, what fantastic info! Muscle is the fountain of youth more than a botox injection or facelift ever could be. I appreciate all of this great, helpful info, including the muscle mass calculator too. :)


23 Mary C. Weaver, CSCS
Twitter: themusclediva
June 4, 2012 at 12:36 pm

Shira, thanks so much!


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