I'm diabetic and am having problems with fountain sodas off and on. It seems that sometimes those labeled diet aren't. I can't taste the difference but notice the bump in blood sugar Upon researching, it appears to be a fairly widespread problem. It seems that if they run out and don't have any diet, a lot of places just hook up what they have. If your on a hardcore diet beware. It is possible, I'm told to test it with urine glucose strips. They are cheap and I'm going to look into it further....