What most androgenic steroids do is increase the muscle:fat ratio to unnatural levels.
ALL bodybuilders who get off will look different six months later. The body has a homeostasis.
Either you attempt to maintain your muscle mass and gain fat. Or you try to keep the body fat down, and you'll lose significant amounts of muscle fast.
It's just how it works.
Overeem probably ate the exact same amount of food after getting off in an attempt to hold on to as much muscle as possible. He got noticeably fatter.
You will never maintain 100% of your muscular gains either, whatever anyone says. Not even if you eat a shitload and accept the fat gain.
Steroids work very well. But most knucklehead bodybuilders will preach to you about hard work without ever mentioning steroids as if they're akin to a regular multivitamin in terms of boost.