Yeah dude, cut out anything that has any food dyes in it or preservatives. A quick google search gave me this list, which is pretty good to start with. Also make sure to cut out high fructose corn syrup, that one isn't on this list if I remember correctly.
http://tpzoo.wordpress.com/2009/07/...ditives-you-need-to-eliminate-from-your-diet/
It might make everyone think you're pretentious or some shit, but they're the ones eating poison. You need to read the ingredients of EVERYTHING you eat. No big names, those are all pretty much bad. The shit you buy in the grocery store like chips and candy and soda are wayyyy worse than fast food. Just make sure you know what you're eating and have a strong ass will because that shit is designed for your taste buds.