How much can your metabolism increase when you gain muscle?
Frivolous calorie-spender!
“More muscle leads to faster metabolism.”
That statement makes sense, right? More muscle, more caloric upkeep. But have you stopped to wonder how it actually works?
As a coach, I’ve read my fair share of fitness tips. And from all kinds of sources too, from your average gym bro talk to peer reviewed papers from the science guys (gym bros with a PHD). When it comes to metabolism, I think everyone can come to a consensus that more muscle equals better metabolism, which means more calories required daily.
Anecdotally, I too am well experienced with this phenomenon. Nowadays, at around 11% body fat and approximately 51% muscle mass, I find myself struggling to eat enough to maintain weight (in a clean manner). Quite drastic of a change compared to my bubble tea-chugging university days.
Is the metabolism boost really as magical as people claim? Let’s find out.
1 pound of muscle is commonly claimed to add 30 to 50 kcal to our basal metabolic rate, which is honestly quite mind-blowing. Using another gross generalization, untrained beginners can add 8 to 15 pounds of muscle in their first year of training. If we take the top end of both claims, we’re looking at an extra 750 kcal (50 kcal x 15 pounds) added to our daily total allowance in just a year’s worth of training.
To put that into perspective, nutrition labels and our dietary recommendation percentages are based on a 2000 kcal diet. Adding 750 kcal is a 37.5% increase. Something’s probably off.
To science we go!
According to a study published in The American Journal of Clinical Nutrition on the specific metabolic rates of major organs and tissues, an average adult burns ~13 kcal per kilogram of skeletal muscle (~6 kcal per pound). Not only is this lower than many bros claim, it’s also set to gradually decrease as we age into our 50s.
How does that compare with the caloric upkeep associated with other parts of the body?
Interesting, right? Think of all the benefits of having a bigger heart!
Jokes aside, despite how calorically taxing organs are, we can’t exactly grow our organs. (Technically, you could fatten your liver, but that’s really not the point I want to make.) So in order to increase our basal metabolism, we look to increase our muscle mass.
With more science-backed data, let’s once again calculate how many extra calories we can consume after a year of training. Taking the same generalization of approximately 8 to 15 pounds of muscle in our first year of training, we get the following: 15 pounds x 6 calories = 90 kcal.
The results are pretty depressing - that’s a year of hard work for 8 Lays chips. But fear not, there’s more to muscles than just increasing basal metabolism!
The overall effect of muscle on metabolism
Keep in mind that with more muscle, the energy we burn during exercise increases too. The calculation starts to get a little more complicated, but here’s a well written article from Stronger by Science, authored by Greg Nuckols, that explains the calculations in detail if you’re interested in digging deeper.
In short, most people have an active energy expenditure of about 1 to 6 kcal per pound of muscle, depending on how active you are. If you’re mostly on your couch or your desk, you’re probably looking at 1 to 2 kcals per pound. Add this to our passive metabolic rate of 6 kcal per pound, and we get a total of 7 to 12 kcal burnt per pound of muscle.
For simplicity’s sake, let’s go with 10 kcal per pound – which represents a moderately active lifestyle. Ultimately, we come to a grand total of 15 pounds x 10 kcal = 150 kcal gained from our first year of training. This extra allowance of calories is certainly not enough to tip the scales (nor is it as magical as we first thought), but hey - as overused and clichéd as this is, it’s a marathon, not a sprint! Keep progressing for a couple of years, and you’ll eventually end up with a whole set of new problems: not eating enough to sustain your weight (this is both a first world and third world problem…dark shower thoughts).
We’re on this health journey right up until we’re unalived, so it’s a good idea to keep investing in every step of it. It’s my humble opinion based on my lived experience. I’m not here to force any ideas on you – just knowledge. And with more of it, I hope you’ll be empowered to form your own informed ideas about your journey.
Anyways, I hope you learned something new from this!
Keep grinding!
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