Fat and water are two different things, hard to distinguish visually. My guess is that he was mostly watery in the off-season.
Ronnie was/is the best of all time, true genetic freak no question.
However he's fat in those off season pics, not just holding water.
If he was "holding water" in his off season why wouldn't he be holding water in the hospital pics?
He's done being huge, so he now stays lean.
Obviously great genetics, and as was said obviously on drugs for life.