I eat a bit more before a long ride, but less out of necessity and more out of "I'll likely burn this off anyway, so why not indulge?" I like pasta, so that's usually my meal of choice before a big ride, but I remember reading somewhere (the New York Times perhaps) that carb loading isn't as effective for women as it is for men.

Now water and hydration is a different story. Even if I don't change my eating habits much before a big ride, I will up my fluid intake 48 hours or so before the ride, especially in the summer. The first thing I do the morning of the ride is down another big glass of water. While it makes for more frequent stops, it makes for a better ride overall.