Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
10 Aug

How Many Calories Does Muscle Really Burn? (and Why It’s Not About Calories Anyway)

The hallowed halls of the Academy of Broscience contain untold tomes of knowledge, wisdom, and recipes for “sick” pump stacks. Over the years, their scholars have elucidated the arcane esoterica of muscle confusion, thereby making it palatable for the layman. They discovered that any gram of carbohydrate eaten after dusk turns immediately to fat, and that curling in the squat rack engages more muscle fibers than curling elsewhere. Their field researchers are reportedly close to confirming the existence of spot reduction. But perhaps their greatest contribution to modern physical culture has been the establishment of the unassailable fact that muscle burns fifty times more calories than fat, at fifty calories per pound per day. (Even Dr. Oz says it, so it must be true.) As they have so painstakingly shown, adding twenty pounds of muscle increases your resting metabolic rate by 1000 calories. With that kind of leeway, you could eat a delicious twenty egg-white microwaved omelet with low-fat cheese and a side of plain oats and never worry about body fat accumulation!

This, of course, is complete nonsense. Broscience is not even peer-reviewed and their application for accreditation is still in administrative limbo.

No, but seriously: the idea that muscle significantly boosts resting metabolic rate is pretty much nonsense. Now, don’t get me wrong. I like muscle. Love it, even. Nothing I like more than a bit of lean mass, but I don’t like how this notion of “muscle burning fat at rest” has taken hold in the collective psyche. It leads to lofty expectations that come thundering down to shatter to pieces. It gets people on a single, obsessive fitness track where all they want to do is lift, lift, and lift (and eat, eat, eat) some more to the exclusion of other, perhaps more enjoyable pursuits. And, it can even negatively impact one’s health or progress toward desired body composition, either via overtraining the heavy lifting and undertraining the other stuff, like sprints, walks, hikes, and simple play.

Anyway, I came across an article several months ago detailing the author’s discovery that muscles don’t actually burn that many more calories than body fat. He doesn’t cite any specific studies, but he does cite Claude Bouchard, an obesity researcher from the Pennington Biomedical Research Center, who revealed that a pound of muscle, at rest, burns about six calories per day (and a pound of fat burns about two). That’s a far cry from the 50 calories per day figure “cited” by others. This number isn’t available in the abstract of some specific study. It’s drawn from extensive reading of the “biochemical and metabolic literature”. If you have literature to suggest otherwise I’m all ears. For the purposes of this post, though, I’ll take Claude at his word.

So, straight from the guy that studies this stuff for a living, muscle doesn’t burn a significant number of calories at rest. To illustrate the point let me quote the author of the LA Times article:

The 20 pounds of muscle I’ve gained through years of hard work equate to an added 120 calories to my RMR. Not insignificant, but substantially less than 1,000. However, I also engaged in a lot of aerobic activity and dietary restriction to lose 50 pounds of fat, which means I also lost 100 calories per day of RMR. So, post-physical transformation, my net caloric burn is only 20 calories higher per day, earning me one-third of an Oreo cookie. Bummer.

Or a single macadamia nut as the case may be. But that doesn’t mean having more muscle isn’t good for body composition and overall leanness, because it definitely is. Let’s look at some of the metabolic and other benefits of having more muscle mass.

Recent epidemiology (13,644 participating subjects) reveals that skeletal muscle mass strongly correlates with improved insulin sensitivity. With each 10% increase in skeletal muscle index (a measure of how much muscle is on one’s body), HOMA-IR (a measure of insulin resistance) saw a relative reduction of 11%. Folks with higher insulin sensitivity have better glucose control (carbs don’t destroy them) and lower rates of diabetes. Another study looked at the relationship between sarcopenia, or muscle wastage, and insulin resistance. There was a distinct relationship between sarcopenia and insulin resistance, independent of obesity, which can also exacerbate insulin resistance. So, based on epidemiology, a lack of muscle is linked to increased insulin resistance and poor glucose regulation. This should go without saying, but sarcopenia was also linked to obesity.

How does one get increased muscle mass? Why, by lifting heavy things. And what does lifting heavy things do to insulin sensitivity in addition to its effects on muscle mass? It improves it. To show this, a study placed older Hispanic adults with type 2 diabetes on a 16-week resistance training regimen and measured their baseline and post-treatment muscle mass and markers of insulin sensitivity. Folks in the strength training group got stronger, leaner, built more muscle mass, and developed more type 1 and type 2 muscle fibers. They also became more insulin sensitive. The increase in type 1 fibers, in fact, was strongly associated with the improvements in insulin sensitivity, as this graph shows. Note how the sedentary group didn’t do so hot in either department (increasing muscle mass or decreasing insulin resistance). That looks like a pretty strong link between increased muscle mass and insulin sensitivity to me.

Why is this important? Being insulin sensitive means you handle glucose well, which means less dietary glucose becomes body fat and less insulin is required to handle your business. This is far better than the idea of having a rumbling muscular engine idly burning calories as you watch TV, mostly because while the latter is a fun story to tell your bros at the gym, it’s not really true.

Having greater muscle mass also acts as metabolic reserve in times of trauma. I’m not talking about famine or starvation. I’m talking about car accidents, internal damage to organs, severe burns, cancer, sepsis, and catastrophic injury. A great review article (PDF) from five years ago summarizes the role skeletal muscle plays in recovery from and survival of trauma. In these unfortunate but very real instances, protein requirements shoot up to repair damage, and muscle protein breakdown increases. More muscle mass means you have more reserves to keep the amino acids flowing. When healing from burns, dietary protein needs increase to 3 grams per kg of bodyweight. If you can’t stomach that much or dietary protein isn’t available to you, it comes from existing muscle. And, if you don’t have much muscle to spare, you’re going to recover more slowly from severe burns. Same goes for cancer patients; those who have the greatest muscle mass tend to suffer fewer recurrences and live longer. Think of skeletal muscle mass as a buffer for hard times.

Finally, muscle looks good when attached to a human skeleton by tendons and covered with skin. And don’t we all want to look good naked, ultimately? Heck, I’d say this last one is enough reason to lift heavy things by itself.

Now that you’ve (hopefully) ceded the “idle muscle burns fat” idea, we need to go further. Let’s stop thinking of exercise and weight loss in mechanistic terms. Let’s not think of “burning” calories by subjecting our bodies to punishment. Sure, you could grind away and, with enough volume and intensity, “burn” off calories through sheer force of will. If your only concern is that you maintain low body fat, you could eat a bad diet and run fifteen miles a day. I did, and I was skinny. It “works.” But isn’t it much more freeing to realize that 80% of your body comp will come through proper diet, meaning you don’t have to grind on the treadmill and you can instead explore the joy of movement for its own sake? Isn’t it more elegant to imagine the hormonal cascade that heavy lifting jumpstarts and which gently nudges one’s physiology toward leanness and away from adiposity? Whether you see it as science, art, or a blend of both, the way we do things is more effective and enjoyable than hammering away at your fat stores.

Some may continue to hold their peace of mind ransom for those 500 calories of donut they just ate. That’s not me. While they’re waiting for “500 cal” to pop up on the elliptical’s readout, I’ll be eating real food, lifting heavy things, and appreciating the beauty of a complex physiological system allowed to do its thing. I suggest you do the same.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Iron Heart by Brian Boyle is great story and a perfect example of how extra muscle and fitness can save your life in a severe car accident when the average person would not make it to the hospital let alone live after having his organs put back where they belong including his heart which had relocated to the other side of his chest.

    Devin wrote on August 10th, 2011
  2. Mark, the first paragraph of this post rules! With all the bad snark on the internet, its great to see someone who can still do it right. (The rest of the post is great, too).

    Broscience. Perfect.

    Duncan wrote on August 10th, 2011
  3. Awesome awesome article

    lisa wrote on August 10th, 2011
  4. “Nothing I like more than a bit of lean mass,…” that’s what she said.

    Sorry coudn’t resist :)

    ema wrote on August 10th, 2011
  5. No evidence here, but just some “food” for thought.
    While it might not be the additional muscle mass in and of itself that contributes to calorie expenditure, could it be the very processes that help maintain that muscle AND the additional work they contribute while exercising at high intensity that offers the real contribution of additional muscle.
    The greatest expenditure while at rest comes from the internal organs and the brain, however those processes are involved in providing the energy required for cell turnover and fiber development.
    All else being equal, larger stronger muscles will contribute more to any activity and calorie expenditure than smaller ones. Again, all else being equal.

    Tom wrote on August 10th, 2011
  6. I love it!!
    I used to be on the hampster wheel, running up to 30 miles a day (training for ultraruns) ate anything I wanted. I thought I was really healthy! Now I perform body weight exercises, lift heavy stuff, swim, paddle and run medium short distances and practice yoga. I eat primal and feel much better and way stronger! I’m enjoying life!!!

    Syllamo wrote on August 10th, 2011
  7. Oh, I forgot barefoot running!!!!

    Syllamo wrote on August 10th, 2011
  8. I recently gave up on my Lotte Berke inspired workout DVDs in favor of Primal Fitness. The DVDs promise to whittle our hips and thighs if we do the dozens of plies every day for an hour. I kept hearing, “Feel the burn! Keep going! Ten more! This is your calorie-burning muscle! After this you can eat whatever you want!” I always thought it sounded like fiction, especially when my jeans got tighter instead of looser. Talk about frustrating. Now I know why. These days my jeans are looser doing less and eating Primal. Thank you for another nail in the CW coffin.

    elise a. miller wrote on August 10th, 2011
  9. 8000 calories a day!?! WOW!!!

    Mark wrote on August 10th, 2011
  10. Great post Mark!! Keep up the work. I have a question that is off the subject… in your experience do you think some women are turned off by fit men? Also, are some men intimitated by fit women? Just a topic to expand on…

    Mark wrote on August 10th, 2011
  11. Someone posted to the Nutrition and Metabolism Society FB group the other day about greater muscle mass being linked with less risk of insulin resistance. I wondered then whether it was because the muscle fended off the IR specifically, or whether it was because people with IR lose muscle mass–you need insulin to put amino acids into muscle, which is why eating protein triggers insulin release. But if muscles are IR already, they won’t be able to grow any and may even deteriorate, which probably explains the beach ball on a stick look that so many middle-aged people have (well, that and abdominal fat).

    So I guess, from what you’re saying here, that actually both are true. Iiinteresting. And this points up why diet is so important. Building muscle might reduce the risk of IR somewhat, but ultimately diet has the greatest effect, and the less IR you have, the easier it will be to build up the muscles, which reduces the risk of IR further.


    Dana wrote on August 10th, 2011
    • @Dana, probably both as you note. Muscles get larger through lifting heavy things. When you lift heavy things, you must burn glycogen stored in the muscles, after which time those muscles want to restore gycogen levels. In order for that to happen they have to become receptive to the insulin that allows glucose (and amino acids for repair and growth) in. That’s why exercise is such a great “cure” for IR. It’s a constant depletion and refilling of glycogen that keeps insulin sensitivity.

      OTOH, when you don’t exercise, you lose muscle mass and you don’t ever really tap into glycogen storage, so the insulin knocking at the door gets the response “nope, don’t need any more glucose here, take it somewhere else.”

      The muscle mass correlation may have more to do with exercise growing muscle AND improving insulin sensitivity than just the observation that less mass correlates with IR. Either way, lifting heavy things will generally improve sensitivity AND mass.

      Mark Sisson wrote on August 11th, 2011
      • That IS interesting. I was wondering, then, if a person is constantly needing to restore glycogen levels–and so the muscles are “sopping up” more of the glucose from the bloodstream–would less insulin be produced in the first place? (Since there would be less of a spike in blood sugar?) Or maybe it doesn’t work that way, I don’t really know. But I was thinking that anything that reduces the amount of insulin released would reduce IR?

        This is particularly interesting to me because I just visited my 18-year-old, who’s been working on a trail crew for the last two weeks. It’s extremely hard physical labor, long days and they get very little protein or fat. And she’s lost a good deal of weight around her waistline and gained muscle. She was hardly overweight to start with but now her belly is sure flat. She already was pretty strong in the arms and shoulders from rock climbing and now she’s swinging a pick to crush rocks for trail drainage and cutting logs with a handsaw in the wilderness areas where power tools aren’t allowed…and building up more shoulder strength. I asked her if she was getting enough to eat and she said sometimes the mosquitoes are so bad they don’t want to lift their face netting to eat! So probably she isn’t getting enough fat, protein OR calories. This got me thinking both about the post earlier relating to countries where people eat almost entirely carbs and stay slim and the link to the article about how people shouldn’t jump to conclusions about the reasons people are overweight. Although I definitely don’t believe it’s all about “calories in/calories out,” calories and exercise do have a role, clearly. It just depends–there are a lot of factors. Well, I gave the girl a bag of protein bars and encouraged her to continue her practice of buying a quart of whole milk every time the trail crews stops at a mini-mart. (In camp, it’s mostly bread and pasta, every day, and they drink powdered sugar drinks right out of 5 gallon bins.) She’s a vegetarian, which makes it even more difficult to get enough calories, fat and protein on the job. But people can and do subsist on carbs.

        DThalman wrote on August 14th, 2011
  12. Dennis, I agree completely!

    Richard wrote on August 10th, 2011
  13. Rob & Jason

    At no point did Mark make a plea that you must believe him or the article sited. All he did was give a hypothesis and site a study that supports it and leads him to believe the way he does.
    The purpose for this article was to pose a question and give a possible answer not come to a definitive conclusion.

    If you have sone information that conflicts then state it. Don’t just bitch and complain that he didn’t do all your research and thinking for you.

    An appeal to authority is saying, you must believe something because so and so believes it, not I believe something because someone I trust beleives it. The second one leaves it up to you to choose for yourself to believe or not, and is a statement of why he believes something not a cry for you to believe it to.

    What do they teach in schools nowadays,

    Josh Kruschke wrote on August 10th, 2011
  14. It’s like Coach Rippetoe says, “Strong people are harder to kill than weak people, and more useful in general.”

    Aaron wrote on August 11th, 2011
    • Put another way, “être fort pour être utile” — be strong to be useful. That was the motto of Georges Hébert, paleo forerunner and father of parkour.

      Timothy wrote on August 11th, 2011
  15. Interesting how something people want to hear soon becomes a ‘well known fact’. Just to add, McArdle, Katch and Katch (2007) suggest that for every lb of lean muscle mass an additional 7kcal per day are burned.

    I know many PT’s who use the 50kcal/lb/day ‘fact’ to sell personal training to their clients, and I can see why – for simplicity: Say you gain 10lbs of muscle, you will burn an extra 500kcal per day, so that’s 3500kcal per week. This is the number of kcal held in 1lb of fat, so therefore you will burn 1lb of fat per week at rest! SOLD!

    Nico wrote on August 11th, 2011
  16. Although resting metabolic rate might only be minimally influenced by muscle mass, what about metabolic rate while exercising?

    Maybe a bodybuilder going for a walk/ run/ swim might only ‘burn minimally more calories’ than a skinny marathon runner, but imagine them ‘lifting heavy things’ to the best of their ability.

    I know that, after a few sets of bodyweight pull-ups/ dips/ squats or bench presses etc, I’m hardly sweating (I’m 1.80m, 64kg, frustratingly losing weight), but huge guys (this kind of applies to fat guys too), after a few warm-up lifts are already in full workout mode; heart rate elevated, sweating unpleasantly.

    Any thoughts?

    Dzoldyinglei wrote on August 11th, 2011
  17. Humans had been dead long gone if our muscles spent so much energy not doing anything. Everything´s evolved for survival. That includes saving energy!

    Wille wrote on August 11th, 2011
  18. Hello Mark,
    Since the subject is muscle, I have a question. I’ve been reading your blog for several month’s now, and I love all of your diet advice you give here. I tried being primal for 2 month’s now, maybe a little longer.
    Today, when I was looking through some of my pictures from 2 month’s ago, and some of my recent pics as well, I’ve noticed a huge difference in my body composition. I’ve lost a lot of muscle.

    Before, I’ve always had a lot of muscle, I workout 4 times a week.
    But in since I tried primal diet, I’ve lost so much muscle, my body doesn’t look the same as it did a few month’s ago. But I train the same, I am a bit confused.

    Tatianna wrote on August 11th, 2011
    • When I started eating primal I initially had low energy and lost some muscle. It turned out I just had to adapt to the diet and eat more. That took some time as so much fat didn’t sit comfortably in my stomach so I had to split up my eating through the day to get all the necessary calories and eat lots of fruit for energy. Now, six months later, I normally drink tea or coffee and eat a bit of fruit and maybe small protein containing snacks through most of the day, as well as a big glass or two of milk during my workouts, and at night I FEAST on protein and fat.. a lot of it.. and I think I’m gaining muscle. I at least have lots of energy compared to before and I keep increasing my endurance. (That might just be due to getting in better shape but I think I just had to adapt after 20 years of eating high-carb). Maybe you should try adding more carbs into your diet from fruit to help with the transition because I think it takes at least a few months to truly get into primal mode.

      Animanarchy wrote on August 11th, 2011
  19. Is there a whiff of an anti-gym agenda in some of the responses here? Some people seem to love to knock gym based lifters.

    I know this isn’t the case, because Mark lifts heavy things in the gym, but the article does come across as a bit of a downer on gym based weight training. It just reads that way to me.

    Remember folks, that lifting in the gym can get dramatically varying results. You can get fitter, leaner, stronger or bigger. It just depends on how you go about it.

    Mark wrote on August 11th, 2011
  20. Another great article. Have to love “Bro Science”! I really like the point on play being a larger part of our fitness. It can be fun to go into the gym and pound out a great workout but even there you have to keep it fresh, do new challenging movements, take it outside for a trail run or, even better, free running in nature. Learn something new. Play like children and if you have children, get outside and just play with them. That is what life is meant to be.

    Erik wrote on August 11th, 2011
  21. Yeah, I got the sense there is some anti-gym sentiment here as well.

    I have several explanations for this:

    1) Many are intimidated and/or put off by many people who go to the gym to lift weights, because lets face it: the majority of those doing it are young immature guys. There is an element of vanity as well, since the majority of these people are doing it for aesthetic or cosmetic reasons. This is not debatable since we all observe the most popular exercises are training the pecs, arms, and abs.

    2) Some have tried weight-training but have not really progressed due to various reasons: improper exercise selection, poor or incongruent diet that would otherwise assist the progress made by weight-training, and lastly lack of a killer-instinct in the gym. I hate to say it, but most people do not work as hard as they can in the gym and do not attempt to get stronger (and thus get more muscle).

    I used to be a skinny-fat guy. But weight-training has changed my life and physique. I also have to say I could not have achieved what I have without training inside a gym. Nobody can get increasingly strong without lifting heavier and heavier weight, and this can only (well almost, unless you have some sweet equipment at your disposal…like heavy atlas stones) inside a gym.

    Those who bash the gym can, but to their own detriment. Not everybody weightlifts for only aesthetic reasons. But even if they did is it so wrong? We all do things (we all visit this site for instance to be more healthy, to look better without clothes) to improve our appearance, albeit differently. That pic of the guy in this post was bashed…but does the person who made that remark know the kind of work needed to achieve that physique? A lot of dedication is needed.

    FYI I am not a bodybuilder, just a former speed-skater that somehow found the gym the past several years. The gym has helped me manage my depression and it’s continually amazing to me how my hard work is reflected in me incrementally getting stronger. I am a proud gym-goer that practices the Olympic-lifts.

    Lastly, for those of you that don’t go to the gym or lift weights: you are likely not very strong (unless you’re very big). You may look in-shape, with abs showing and everything, but that doesn’t mean you’re strong. I will offend, but it is true.

    But who needs strength you may ask. I do, but it’s not for everyone.

    Ewan wrote on August 11th, 2011
    • I think what can be achieved in a gym is very much underestimated and misunderstood. I’d expect that from the wider population but I thought the PB crowd would be more enlightened. There is too much anti-gym snobery IMO. The prevailing CW about ‘gym rats’ needs to be challenged. The gym is the ideal place to get fit, to burn body fat, add some healthy lean muscle and improve your functional strength. You just need to know what you are doing. Most people don’t.

      BTW, Once a week i do sprint training and functional outdoor training. Stuff like dragging tires, bear crawling, lunging with beer kegs etc.

      Mark wrote on August 11th, 2011
      • hi Mark,

        I agree with you. The gym is very much misunderstood, even amongst the PB crowd.

        I am a ‘gym rat’, mind you. The gym is my sanctuary (when I’m not doing experiments — I’m a PhD student in evolutionary biology). Many hold the stereotype that all gym rats behave a certain way. Far from it in my opinion. I get a lot of intellectual stimulation from immersing myself in technique and programming.

        Those who have never put in the time in lifting iron will never appreciate and understand the explosiveness and absolute strength that can be garnered through barbell training.

        Perhaps the gym is an artificial environment that doesn’t fit with ideal PB philosophies? Maybe outdoor ‘Strongman-type’ training (as you do…btw I’d love to train with you!) is more applicable? But then again, I feel those who are anti-gym would be anti-Strongman as well.

        Their loss.


        Ewan wrote on August 11th, 2011
  22. great article, thanks Mark. I love that eating primal + crossfit with a strength bias esque training means I dont have to worry a damn about calories. And that’s calories down the pie hole or calories that may or may not be burned in or out of the gym. Who cares about calories when you eat good food until your full and carry a 6 pack.

    alan wrote on August 11th, 2011
  23. As long as Dr. Oz agrees with it…then its all gucci.

    Robin wrote on August 11th, 2011
  24. “and that curling in the squat rack engages more muscle fibers than curling elsewhere.”


    … and when you ask them to move, point out that girls have no business in the squat rack in the first place. Bro.

    That’s exactly how it went on my lunch break.

    Lauren wrote on August 11th, 2011
  25. Great article, and at just the right time. Thanks as usual. I think some people are being hyper-technical/critical however–and that was not the point of this article.

    I think the point was lost that has been stressed time and time again in the book and on this site–don’t get bogged down in the minutiae od kcal in and out, RMR and other things–that is why so many burn out so easily.

    The way I see primal is that the underlying science is critical, but MUST BE BALANCED by the overall philosophy of not over thinking things and possibly not enjoying the journey.

    exilio wrote on August 11th, 2011
  26. A professional athlete of ANY kind should NOT be used as an example of anything, since they basically burn their candle at both ends for a living; it’s no wonder they burn more calories, but that’s in a day– not a lifetime, since they DIE much sooner too.

    If you’re trying to IMPROVE your health, don’t look to someone who places health secondary to performance… it’s like taking auto maintenance tips from the demolition-derby.

    Brian Armstrong wrote on August 12th, 2011
  27. I love your reference to moving for the sake of the joy of movement, of play. A lifestyle comprised of punishing workouts for the sake of eating more, is a sad life indeed.

    Once tapped, the instinct to play is powerful. Great and very thought provoking article, whether you agree with it 100% or not.

    don mcgrath wrote on August 13th, 2011
  28. After reading those articles I don’t want to build more muscle I want more organs. Livers would probably be easiest. I could have three extra livers spliced into my system. Then my RMB would be up by 60% and I’d be able to eat all the pizza and milk shakes I want. I could keep the extra livers on my back disguised as babies or a back pack. And if I ever need another liver, I’m ready. Win, win.

    SugarySnax wrote on August 18th, 2011

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