A couple things to add here. I qualified for trials in 2000 and went through the same carb intake problem thing then. Problem for me is that I have juvenile diabetes and I have to take insulin shots. This kind of makes me a "test-tube" experiment for carb metabolism because I have to control my metabolism with shots of insulin and taking in carbohydrates - in short, I know exactly what my metabolism does because I can measure mine. This is what works for me: a MetRx bar 60 to 90 minutes before the marathon, then start using gel at about mile 6 (not a whole packet at once, but a little squirt every minute until the pack is gone in about 5 to 6 miles). Another pack of gel, a little at a time, by mile 18, and one more by around 24. No more gel for the last two miles. I use only water when I'm using gel because the gatorade or whatever will make me puke when I'm using gel. I puked for the last 8 miles of my first marathon because I used gatorade with gel. Never made that mistake again! I always carry 4 packs, just in case. Don't use safety pins because you'll have a gross, sticky mess in your bun huggers. I use those little black binder clips that you find in office stores. They work perfectly. Also, clip the packs on the upper inside of your running bra. The inside of you huggers or shorts lets them move too much and over such a long distance, the edges will cut your skin open. Been there, done that. If it's cold enough to wear gloves, you can stick one pack inside the back of each glove and it won't bother you. I will agree with "confused" though - you should have practiced this in training way before now. It's called practice for a reason.