I have been reading "Nutrition Periodization for Endurance Athletes" by Bob Seebohar. He is a Registered Dietician who works with Olympic Athletes among others.
He talked about how and what we eat. The thing he said that resonated with me was that we should eat to train, not train to eat. Having struggled with my weight for pretty much my whole life, I really did start running to be able to eat more.
Once I started racing, I discovered training and started working on being a better runner. Part of this progression is that I have had to look at my eating and hydration habits for more than just weight control.
To me, eating to train means that my choices of fuel and hydration and their consistency are the things that prepare me to run--the meal I eat the morning of my race, while it may help me is not the determining factor in my performance.
I've always said that running is a cummulative event--it is not a History final, you cannot cram for it. I hope I can continue to do prepare and not cram.