All that we had to do was train and adapt his muscles so that he could be more dynamic and explosive, and be able to perform more quickly.
And the only way to be able to do that is that you have to be able to understand that one pound of fat is the same as one pound of muscle.
I'm not sure if I follow what's being said by Heredia here. Is he explaining the consistency in Marquez' weight, in other words that his body has been reconstituted (far to muscle) instead of getting heavier or lighter?
If he is, then the only problem with that is that it's quite difficult to simultaneously lose fat and gain muscle, especially for guy who's 38/39. You can do it, but it takes a lot longer to gain muscle mass, and bulk/cut cycles are probably preferable.