It made me stop eating **** all the time. I'm still too lazy to cook, but instead of taking the tasty way out and just grabbing some fast food, I'll eat oatmeal or something less poisonous to my body.
Also, though I doubt many people on these forums will seek to discredit the movie, I need to say this in anticipation of the inevitable. Yeah, everyone understands that if you eat anything for 30 days, you'll have harmful health effects. What you, the person who goes and points this out, should understand, is that the whole 30 day thing works as a ploy to spread the movie. "Did you hear about the movie where the guy ate McDonalds for 30 days?" Its a gimmick, whereas the movie's message is important and informative.