Well here is the trouble.
Before a marathon, I usually carb load. Whole wheat pasta for me (pasta night is always guaranteed before a good marathon) or, if we are out of town and out of our element. My friends and I go to Chipotle and get extra rice. (starving right now and it is midnight!)
The "trouble" is that I have had 3 dietitians tell me carb loading is fake and really doesn't do anything. I didn't believe it and I did do some research (grant it I am not a registered dietitian), but I did see studies where carb loading proves nothing substantial as a pre-marathon meal as opposed to any other well-balanced meal. The research states that athletes who metabolize at a higher rate (anyone who runs a half or full marathon) will use the carbs ingested the night before right away. Carbs don't store well, they are for use within a reasonable amount of time.
Take it for what you will. I have carb loaded before marathons and I have not (actually got a damn doner in NY once, that was dumb) but at both marathons, I felt the exact same way--really fcking pissed that I was up at 5 am and about to run a lot of miles.
My advice is to go with a good, solid meal and do not dive off the deep end ingesting 2lbs of angel hair pasta.