You know, I was invited to go watch Super Size Me in the theater with a Catholic youth group, and I more or less believed every claim and depiction that was shown on-screen at the time. After all, this guy was consulting with actual, reputable physicians about his condition. And everyone knows that McDonald's food is horrible stuff to begin with.

https://en.wikipedia.org/wiki/Super_Size_Me#Counter-claims

But I was unsurprised, years and years later, to discover that Spurlock's extensive and growing liver damage, and other adverse symptoms, were being helped along quite a bit by his severe alcohol abuse throughout principal photography. It really sort of drove home that there is more than one side to this story they put up on screen, no matter how much they appear to seek and depict the truth.