T Nation

Question about metabolism and muscles

Ok, this might sound a bit dumb but I’ve always heard that the more muscle mass you have, the higher your metabolism is. But why is that? Is it because your muscle breakdown (catabolism) is excellerated and muscles obviously weigh something? And/Or is it just the muscles themselves that have some unique effect on the metabolism like the higher intake of nutrients they need to maintain mass?
To put it simply, if I were on a diet, would I lose more weight with anti-cortisol supplements or less? Thanks guys.

I don’t think there’s any magic to it.
I’ve seen estimates (no basis given)
of 50 calories per lb LBM, but in my
own case, a 50 lb LBM gain has been
worth only about 1000 or maybe 1200
calories. That would be just 20-24
calories per lb.

The added muscle no doubt burns calories
because muscle expends energy simply maintaining tonus, and also because
you are moving more weight around when you’re
active.

Let’s say my 20-24 cal/lb figure is correct.

If that were true for all bodyweight, then
a 200 lb man would burn 4000-4800 calories
per day.

That is somewhat more than actual, but
it stands to reason that muscle weight could
burn more calories than fat or bone weight.

It is because muscle is highly metabolically active tissue, has a large blood supply and it has an energy cost associated with it. It takes energy in the form of your calories just to maintain muscle…even if you do nothing but sit around all day.

Joe: In simple terms (this actually is some pretty need biochemistry!) it means that the muscle is much more energy producing and consuming. Producing because of the much greater concentration of cellular “energy” or ATP producing “factories” known as Mitochondrion. Consuming simply because of a much greater activity of the enzymes involved in carb, fat and protein metabolism.(Both oxidation and synthesis). (Whew!) If a basic biochemistry or Cellular Biology course is a possibilty for you, take one; it’s pretty neat stuff! Muscle is amazing tissue (and I didn’t even get into the biochemistry of muscular contraction!)