Why does bodybuilding / resistance training burn fat?

This was very pondering to me when i started my journey.

We have always been told that we shoul do cardio for fat loss. But this is not true.

There is a way to manipulate your body and your BMR (basal metabolic rate) so that you actually burn more calories by doing absolutely nothing.

Now to debunk this we need to get a little technical.

According to science 1 kg of muscle will increase your BMR by aproximately 15 kcal per day (McClave et al., 2003). That does not sound like alot. Even if you consider the total energy spent extra on a month it is only around (30×15) 450kcal extra per week.

And some will have you believe that this is the end of the story and that is why you should do cardio.

But as usual if you dig deeper this is only partly true!

It is true that if you do absolutely nothing with that extra kg of muscle you have gained that you are stuck with an extra 15 kcal per day – and even adding 10kg of muscle (which is alot) will only improve daily expendure with 150kcal / 4.500kcal pr month.

But what if you use the muscle ?

This is extremely interesting because it turns out that if you are using that 1 kg of extra muscle for training that 1kg of muscle will burn an additional 20-40kcal depending on intensity (moderate to intense training).

Adding to that comes the EPOC (Post Excersize Recovery) where the muscle is beeing rebuilt. This also draws energy up to 48 hours after training. For 24 hours this will give an additional 5-15kcal.

Therefore if you use the beforementioned 1kg of muscle in your workout you will burn in total an extra 50-70kcal and not the initially stated 15kcal.

Looking at a month that 1 kg of muscle burns between 1500kcal and 2100kcal extra.

And yes you can now imagine what 4 extra kg of muscle will do for your metabolism (6.000 – 8.000 extra kcal per month!)

These charts show within a certain margin what will be burning the kcalories post workout.

Also you will notice that the lower graph says “+high-protein diet”. This is also interesting but we will cover this in a dietery blog post. However (spoiler alert) eating a high protein diet will elevate your BMR even more.