I was a faithful powerade zero drinker for the last year. I seemed to do good with it. I had a flair, and thought it was the powerade. I switched to the Gatorade G2, and now I'm so constipated.... Any thoughts? Anyone know if these are gluten-free? Web sites aren't specific enough for me, and the most current post I can find on the web is from 2011. Anyone have any other suggestions? I like the magnesium in them, and I can't stand straight water. Thanks!