Judging from the language of the class action suit against UCAN, too many folks used it without doing a little research to understand the effects of carbs on the digestive system. Lots of people get gassy from carbs, especially rice and pasta, and the effects of sugar alcohols and even maltodextrin are pretty well known. Heck, even beer can cause intestinal gas for some folks, and unpasteurized beers, especially milk stouts, can be even worse.
Carbs and sugars are great for fuel but they aren't free of risk.