So true, once you realize that eating two ice cream sandwiches is a huge deal instead of a small one you start to think of things a bit differently. I could eat 650 calories of junk that will fill me up for about 30 mins eat something else that wont taste as good but be more filling.
I use to never think about calories and stuff, until I really understood caloric intake and how many empty calories things like soda, honey buns, and pizza gave you. I still enjoy those things but instead of eating junk twice or more a day its a once a day thing, and if I burn up all my calories in one sitting well my punishment is starving the rest of the evening. For me that works well... for others it might not so much.
It's gotten me to a point where I just dont want to waste 600 calories on a large fry or 300 on a soda.