You are thinking of a PSA from Fox Kids' 'Totally for Kids' ad campaign, which would have run on TV between 1993 and 1997. I am absolutely positive that this particular one was not part of the initial ones in 1993, but it most likely premiered in early 1994. Nevertheless, the PSA featured John Walsh and the Totally for Kids Detective Agency (which were not featured in every PSA) and they help a young girl make a better choice by eating healthier food rather than junk food. She initially eats junk food and enters into some realm for kids who eat junk food. The bounce-house kind of world you speak of is called 'the hyper chamber', where kids who are too hyper from eating sugar go. She then falls into the dungeon where she sees a kid who has spots all over his face...I assume this was supposed to insinuate that eating junk foods like chocolate causes you to have acne...In the end, the girl is saved from the junk food realm by the Totally Kids Detective Agency after they convince her to avoid drinking sodas and eating candy by instead eating a sandwich.
I do not believe I have the entire PSA in my vast records, but I know for sure that I have bits and pieces of it (on multiple tapes). Unfortunately, I have no idea which tapes they are on. I'll try to look for it and if I find it, I will encode it for you. Nevertheless, you can see other 'Now A Message Totally For Kids' PSA's that were encoded by me on Youtube. I personally did not upload them to Youtube, but I was the one who made them (They are currently down on my website, so you must go to Youtube to view them).
Hope this information helps.