Up front I'll state that this post isn't about the danger of processed foods, the injustice that fastfood companies have done to the health of our nation. Although interesting topics, and probably ones that are worth consideration, I try to be a bit more simplistic in my eating values.
I've recently tried to be "cleaner" in my diet: more fruits and vegetables, less fried items, I'm trying to avoid candies and a lot of snacks (baked good is where I struggle the most), and smaller portions. I know that there have been scientific and statistics that talk about this. For me, however, it's simply about the way that my body feels.
I find that days that I'm not conscious about portions or about what I'm eating, I'm lethargic and don't feel optimal.