In all fairness, you were warned. The Amazon description for sugar-free Haribo Gummy Bears reads, in part: "This product is a sugarless/sugarfree item with ingredients that can cause intestinal distress if eaten in excess."
"Intestinal distress," in this case, might be an understatement for what a series of viral Amazon reviews call, "trumpets calling the demons back to Hell," "guttural pronouncement so loud it threatened to drown out my own voice," and "100% liquid. Flammable liquid. NAPALM."
So why is it that gummy bears, an otherwise delicious, springy snack, become so sphincter-confounding once the sugar is removed?
A glance at the nutrition panel shows that the first (and thus most prevalent) ingredient in the sugar-free variety is lycasin, a hydrogenated syrup. Lycasin, meanwhile, consists mainly of maltitol, a sugar alcohol that is almost as sweet as table sugar but half as caloric. Maltitol is great because it doesn't cause cavities, but not so great because our bodies can't fully digest it, so it can ferment in the gut. The known side effects of the excessive consumption of lycasin are bloating, flatulence, loose stools, and borborygmi, the scientific term for tummy-rumbling.