Dustin Diamond alleged in Behind The Bell that Mark-Paul Gosselaar took steroids between his stints on Saved By The Bell and Saved By The Bell: The College Years. Of course, Mark-Paul Gosselaar's change in appearance could easily be due to simply working out and growing up, and there was never any real evidence that he was juicing up. The Franklin & Bash star never addressed the rumors specifically, though he did side-eye Screech's tome, telling interviewers, "Everything that I've heard about his book is negative and I don't remember those things. My experience on the show was very positive and that's why when people say, ‘Oh, you don't like talking about it.' It's like, No, I don't mind talking about it, I just don't really remember that time, and also everything I do remember was extremely positive."
Mark-Paul Gosselaar as Zack Morris on 'Saved By The Bell: The College Years'