Thanks for your responses! SoupDragon, in answer to your question, when I'm eating crappily, I notice that I'm more tired, and also have more seemingly random mood crashes (where I go from OK to feeling horrible in the space of a few minutes, without any obvious external cause)... probably related to blood sugar. I also will crave sugary foods more, which likely just continues the cycle. When I'm at work, I usually eat relatively unhealthy cafeteria food. Last night, I brought a garden salad and fresh fruit, and I noticed that I was more alert and less exhausted than usual at the end of my shift. I'm also finding that having high protein snacks (i.e., trail mix or a cheese stick) helps keep my energy level frrom crashing.

I've also been reading that drinking lots of caffeine is actually bad for your energy level... that it causes a brief energy spike, and then a crash. I'm not ready to go there yet... I do like my coffee in the morning! I guess, for me, it is a process of making small changes here and there, instead of abruptly changing everything at once.