I read an article in the NY Times called Six Meaningless Claims on Food Labels. I don't know how this doesn't violate false advertising laws. One reason, I suppose, is that there is no standard definitions for claims like "all natural." But when things like fruit snacks become "all natural" there's definitely some intense marketing (read: lying) going on.
I've only taken one nutrition class. It was an intro class, a prerequisite I had to take for nursing school. But just the basic information I learned there has served me so well. It also was the beginning of what I hope is a life-long love affair with vegetables. Seriously, they're wonder foods!
For example ingredients on a package are listed by weight in descending order. So if something claims to be "whole wheat" or "seven grain" or "super healthfoodlicious" but the first ingredient is sugar or enriched flour (meaning that by weight there is more flour or sugar than anything else) then you know it is not as nutritious as it claims to be. I don't know if that's something that most people already know. I didn't learn that until college.
I always read labels. It helps me to be able to buy food with the least amount of processed ingredients and additives. And reading allows me to evaluate what I am buying despite what the marketing claims may say. Anyways, if you want to know more you might look at the article. It's short and it has some additional resources at the bottom, I believe.
Also, aren't my cats cute?!?