Since American football has existed, there have been fat, lazy defensive linemen. There will always be fat, lazy DTs. Particularly fat ones.
And then, rarely, there will be the Casey Hampton of the bunch. More likely, someone you dare to mention in the same breath. Fat but with a motor. Ones who aren't just hard to budge, since they're so fat, but who get after the ball. TFL. QB sacks. Causing fumbles.
Herman's not going to make that fat disappear, but maybe he can motivate some into developing more of a motor.