Before Boston I tried Crazy Jason's glycogen depletion/carbo loading. I felt wasted during the process and had a bad race for a lot of reasons which I keep written in my wallet. For Chicago I am just going to increase the percentage of carbs in my diet for the three or four days prior, and lots of water.
I have never run close to Jason's times, so he's a better authority. Everyone's different so my only suggestion would be not to do it for the first time before a big marathon. Here's Jason's deal:
6 days out until 4 days out:
Begin carbo depletion. Eat a little fish, lots of raw veggies, some cooked veggies and LOTS of water. Jog about 90-100 minutes each day SLOWLY.
3 days out:
Begin to put carbs back in slowly today.
2 days out:
Eat your carbs! Maybe do 1000 at MP or rest.
1 day:
Maximize rest. Have a fight with your wife over dinner about how you have been tense all day.
Marathon: Take the bus to Hopkinton and lay around for four f***ing hours while it gets hotter and hotter. When it's 87 you know it's time to get up. Get bad directions to the start line from a fat cop and wind up at the very last corral. Struggle in a panic to get to the front while Hopkinton residents threaten you with brooms because they think you are trying to pee on their lawn like everyone else. Have a bad race. Force a smile when your co-workers congratulate you. Write down your excuses and keep them in your wallet. Strive to do every single thing differently in Chicago.