if you havent, you should rent coffee and cigarettes by jim jarmusch. there is a priceless segment featuring the rza, gza, and bill murray. rza drops some serious science regarding things that arent good for you.
I tried that with Jack in the Box. My undoing was in the fact that it's literally withing spitting distance of my apartment. Still, I got three good months out of my self-imposed fast food abstinence. I think in the end that will amount to four minutes added onto my life span. I won't vouch for the quality of those moments, though.