Well it really depends on what you're trying to do. Most people who body build look toward bulking up for a start, in which case cardio isn't essential. It starts becoming more and more necessary if you want to cut up though, and actually have some body definition as opposed to just being a huge glob of mass.
I've just started with it, but I've found it's important to do it just to feel healthy. It just doesn't feel too pleasant to constantly eat as much protein and carbohydrates as you can, then push your body to its limits, without actually being fit.
So even if someone is just bulking, it could be nice just to do like 2 or 3 20 min sessions of cardio a week.
And aside from that, it just feels really disappointing having very defined abs, but not being able to see them through all the fat, haha.
I don't take any protein shakes, nor any other supplements at the moment. I may start soon though. I've read that the best way to get protein to the body is through ingesting meat anyway. There's too many supplements out there... wouldn't even know where to start, haha.
. Props to you if things like that comprise your diet \m/
