I Googled "Sports drink GI distress" and, after a little poking around, came across a story about Skratch labs. The writer complained about the same problems that I had, and the way that Skratch labs had approached this problem:
I found the company's website and checked out their list of retailers. Luckily for me, BikeWerks, a cycling shop just a few miles from here, was listed as a retailer. At $19.95 it seemed a little expensive to me, until I realized that this packet was the equivalent of 20 16-ounce sports drinks. And at 80 calories for 16 ounces, I didn't have to worry that I was going to overdo it on sugar if I started trying it during my training.
I mixed up 16 ounces to drink before my run today, and even though it was 86 degrees, I felt pretty good after running. No GI distress, no headache. For a short run like this, I would never use a normal sports drink, but since the calories and sugar content of this are so low, I thought it was worth it to practice.
I like their approach to postrace reccovery, too. Instead of offering some kind of weird protein drink, Skratch has two cookbooks, one for portable food for during and after a race, and one for everyday. I just ordered both books and as a bonus, got a free pound of drink mix. I just found one of the recipes online, if you want to get a sense of what they're like. I will review the books after I have tried some of the recipes.
As Skratch Lab's Allan Lim said in his interview with the Philly Enquirer, "Until we could figure out a way to make a protein recovery drink that tasted as good as a bowl of chicken-fried rice, we'd keep making chicken-fried rice."
This is a food philosophy that works for me. No weird bars, no creepy protein drinks -- just food that looks like food.