What do you think of a "soda tax" to discourage people from drinking so many calories? Is soda really the leading cause of obesity?The latest proposal for a "soda tax" comes from a prestigious group of researchers. These scientists authored a review of studies examining the contribution that sweetened sodas, energy drinks, sports beverages, and iced tea have on obesity, and published it in the September 16, 2009, issue of the New England Journal of Medicine. The group advocated a tax o