It took a bit of trial and error to come up with an energy drink that tastes good and works well for my GI.
The basic energy powder mixture is this:
* If not adding additional sugar later, use only 2 packs of Koolaid, unless you like it sour.
Pour ingredients into a big container and shake for a while. For a 700 ml bottle, use 2-3 scoops (50 – 75 g) for 190-280 cal. Add 2-3 tablespoons (120-180 cal) of Karo corn syrup, and fill up with water.
In researching what goes into making a good energy drink, I ran across this study that summarizes everything that I believe to be true from reading various other articles: http://home.trainingpeaks.com/articles/general-fitness/the-straight-dope-on-sugar-in-sports-drinks,-by-matt-fitzgerald.aspx
In order to intake more than 250 cal/hour from maltodextrin alone, which is the maximum amount of carbs that can be absorbed through one absorption channel through the gut, I experimented with adding different kinds of sugar:
The first thing I tried was fructose. Fructose is a neat type of sugar in that it is somewhat slowly digested, but completely independent of maltodextrin. Some people, however, like me, are a bit fructose intolerant. Here’s an easy test to do: drink a big glass of apple juice and go for a medium-level bike ride lasting at least an hour. Feeling bloated and getting stomach cramps? Probably best to stay away from fructose-only sports drinks.
Fructose is more easily digestible when it comes with glucose, so I tried sucrose next. Instead of going for plain table sugar, I opted for coconut sugar. Coconut sugar is basically table sugar with a bit more minerals, so it consists of fructose molecules bound with glucose. This didn’t suit my stomach terribly well, either.
My next trial was glucuse: Karo corn syrup, to be exact, which contains a lot of glucose and di-glucose units. During the 100 mile race when I first tried this, my stomach felt no worse than it usually does. I had some GI bloating after 6, 7 hours. but not bad enough to stop me from riding. My legs had plenty of energy.