Of course you can't go around eating pizza and potato chips all day every day. But keep in mind a dude like the Rock has ppl fixing him 10-12 meals a day(at no cost to him), access to the top illegal PEDS that is the safest as that kinda stuff can get. The Rock is a billion dollar investment so he's gonna have it all. He's likely taking 3-5 different types of stuff. Take him off of it and you'll see him shrink down like he was when he did that football movie several years ago.
It IS just as easy as taking PED's
People just don't have access to it or they don't wanna deal with the side effects of it.
If you have any sort of self-discipline PED's can do wonders for your physique.