Talkiet: Coke Zero. I am going to ignore any hysteria about how unbelievably dangerous the ingredients are since they are able to be sold in the USA with the FDA and Lawyers piled 3 deep in many places looking for class action suits, and focus instead on how it tastes just fine, and calorifically is basically water.
Devils Advocate: Cigarettes are also able to be sold it the US - but there is little disagreement they are horrifically bad for you