How many calories does 1 kg of muscle burn at rest? We keep reading figures like about 100 calories per day, but in reality, the figure is much lower. These numbers don’t refer to how many calories muscles burn at rest. They refer to the increase in protein turnover in the entire muscle mass during training. If you're training hard and regularly, you are not only increasing your muscle mass, you're also increasing the protein turnover in the muscles and of course you boost your metabolic rate. So, all these crazy numbers are not actually about the amount of calories burned by muscles at rest.
So, how many calories does muscle burn at rest?
About 13.0 kcal per kg or 6 calories per pound! Now that’s not anything to write home about. As you can see muscle has a very low metabolic cost when at rest and in fact your internal organs burn a lot more calories per day. More specifically, the brain burns 109 calories per pound, the heart and kidneys about 200 calories per pound and the liver 91 calories per pound. As for fat, it only burns 2 calories per pound.
Where does this myth actually come from? Nobody knows. It’s just one of these myths that have been around for ever and is now a dietary dogma that is no longer questioned by anyone.