GI issues with Gatorade?

Took me two months to figure out that the sports drinks were causing my gi issues when I went through this.  For some unknown reason, the dyes affect me adversely during training and racing.  Therefore, I forego foods/drinks with dyes for about 12 hours before working out, and about 2 hours afterward.  Which pretty much means all the time during the racing season. 

Some useful replacements for me include: nuun, any of the clear sports drinks, hammer products (typically dye free and free of anything that causes others' gi issues like gluten), and one specific flavor of gu that doesn't appear to have any dye.

I hope my experience helps.

Like every other metabolic process, you have to train your digestive system to function well under stress. It doesn't happen in one ride- or one season. It takes a couple years to adapt to being able to absorb calories effectively from different sources during exercise- and environmental factors influence absorption rates as well. That's another reason it takes time to adapt.

Give it a year. Keep at it. Experiment and don't give up. You're going to have bad stomach days. I remember a photo of Greg LeMond from the Tour de France, suffering on the bike, diarrhea streaming down his legs from under his shorts. After the stage Le Mond simply sponged off and said, "I had a bad stomach day."

Once you get acclimated you can take a wide range of things at an aid station and not suffer problems. It's like anything else in our sport: no quick fixes. Eventually we adapt with consistency and persistence. Nothing comes easy.