Read this:
http://sportsmedicine.about.com/library/bl_acsm_fluid.htm

I think Gatorade fits the amount of sugar that should be in the drink for optimal absorption. I started making my own sports drink with the following recipe, very easy to make:
Recipe (makes 1 quart):
1/3 cup sugar (about 5 tablespoons)
1/4 teaspoon salt (or use Morton's lite for some potassium)
1/2 package of your favorite kool-aid, unsweetened of course
mix in 1 quart water, adding the kool-aid last