First, keep in mind that glucose is NOT converted to ATP. Glucose is broken down to water, plus carbon dioxide. There is another process the body uses from taking one of the ions of glucose and using it to drive another reaction of ADP + phosphate= ATP. How much ATP is produced is dependent on if the process is done during anaerobic efforts or aerobic efforts.

See the post I did recently about the Krebs cycle for a better understanding... I greatly simplified this explanation I gave above for the sake of time. The thread with the better explanation: http://bikeforums.net/showthread.php?s=&threadid=20602

If you're planning for a long endurance ride, the best thing you can do is carbo load the night before, then bring some snackies on the trip that will convert energy over several hours upon eating, like a powerbar, or a banana.

If you're just planning for a shorter endurance ride, consider eating a light carbo meal before leaving (like a half an hour so you can fully digest the meal and not ride on a full stomach) and carry a snackie along just in case. You never know if you consumed enough carbs!

If you've got a high intensity ride you're planning, best to eat about half an hour before leaving- something high carb. Then you'll probably want something the body can quickly use for a glucose source in case you start to feel like you're bonking. In this case, something with simple sugars is best- gatorade and Gu are the first things that come to mind.

Proteins have little to do with this- it's not entirely useless, but when you're needing a quick energy source, it's easier for the body to break down say a bananna for energy than a steak! So for your optimal performance, choose that bananna over the steak anyday as your quickie energy source!

Fats are a bit different. I'm not sure what you're meaning by lack of fats, except maybe foods high in fat? Or lack of fats in the diet?

When eating for performance, just think carbs- simple (gels and gatorade) vs. complex (banannas and energy bars) and consider which situation you'll be riding under, then eat for your optimal performance!

Koffee