Is there a precise definition of what constitutes diet soda?  Of course, it includes things like Diet Coke and Diet Pepsi.  But what about non-carbonated beverages like Crystal Light lemonade?  Even if I believed the headlines about this study--which, as the previous commenter pointed out (and any deeper investigation about the study itself makes clear)--are over the top, I still wouldn't know whether I ought to give up my lemonade or not.