How much does muscle mass really increase your metabolism?
We have repeatedly heard that building muscle mass increases your metabolism. But how accurate are these claims?
Does an increase in muscle mass increase your metabolism?
Yes, it does!
But by how much?
The answer may surprise you.
A study found that an increase in lean muscle mass does increase your basal metabolic rate, but by a whopping 13 calories per day for every kilogram of extra muscle tissue you build.
No, that’s not an error!
The study which measured the increase concluded the paper by saying ‘the change in RMR was non-significant and non-meaningful; thus, this study contradicts the commonly held anecdotal perception that an increase in skeletal muscle mass will result in a significant increase in metabolic rate and daily energy needs.’ You can read the study here.
I know, I was surprised too.
Especially when we consider how long it takes to build 1kg of muscle mass. I covered this in my last LEARN blog but let me cover it again here. Some people assume that eating more protein will lead to a faster rate of muscle growth. Still, the amount of muscle we can gain as a natural trainee (someone not on performance-enhancing drugs) is far less than you’d think, depending on your training age. For example, a woman who has been resistance training for less than one year can gain a maximum of 5.4kg of muscle mass per year (as an absolute maximum). This is because the untrained person will gain muscle much faster than a trained person, and the more advanced you become, the slower the process becomes. So if we look at the muscle growth potential of a trained woman, it decreases to a staggering 680g per year!
Yes – that’s 680g of muscle mass over twelve months compared to 5.4kg in an untrained woman.
It is worth considering that someone who has never resistance trained before has a unique potential to grow muscle mass fast! Let’s look at the muscle-building potential of a newbie I mentioned earlier (5 or so kilograms). They may increase their metabolism by approximately 65 calories per day. Which isn’t mind-blowing, but it is something. Unfortunately for the trained athlete, aiming to increase muscle mass purely to increase metabolism probably won’t make a meaningful difference.
So does that mean we should ditch resistance training?
Not if you want to build an elite-level physique or promote quality of life. Mark and I often stress the importance of not seeing resistance training as a means to ‘burn’ calories. There is no doubt that cardio burns far more calories than resistance training when time is equated between the two. But we don’t resistance training to burn calories – we resistance train to build lean muscle tissue, which:
- Improves overall aesthetics.
- Increase bone mineral density.
- Strength decreases the risk of injury.
- Improves muscle mass and balance.
Cardio is a tool that we use to increase energy expenditure in a fat loss phase when food consumption is getting too low or to speed up fat loss. But resistance training is and always will be the main focus of our training programs.
Why?
People often think that to build the physique they dream about, they must get leaner and leaner. However, we find that those who haven’t spent time doing the groundwork (building muscle) lose fat only to find that they don’t look the way they envisioned. So, if your goal is to have a bikini body physique, you shouldn’t live in a calorie deficit, and you should even consider doing a building phase (scary, we know), but it is how some of the best bodies in the world have been built – which says something!
Yours in health,
