Okay, here's my stone to throw in: the evil E word.... evolution baby!
If most of us were originally hunter/gatherers, then we got meat sporadically... but were primarily vegetarians..... now I've read that certain cultures (more linked to DNA, to establish origins than culture) are more accustomed, or their bodies are more atuned to a vegetable-based diet, or a meat-based diet. If this is true, then we really can't "sell" our opinions about what is the best diet to have, without first accepting that we're not all built for the same types of foods. Some cultures can eat all sorts of carbs (rice for example) and be super skinny, where another culture may try living the same way and not have the metabolism to process it properly, gaining weight/becoming fat.
I know I'm rambling, but there's truth up there somewhere, eh?
My personal conclusion is: find out where your heritage originated (sometimes a bit difficult!), and build your diet on that. AND DON'T EAT FAST FOOD!! duh....
