The so-called "sugary drink tax" is a topic we've been following on FutureOfCapitalism.com for some time (see, for example, here, here, here, and here). The topic even came up the other night at the Aspen Institute/New York Public Library event about Capitalism and the Future, as PepsiCo's CEO, Indra Nooyi, was pressed about whether her company's flagship product (not to mention some of its snack foods) contributed to child obesity. She responded by saying her company is pursuing a three-city test to put physical education back into schools, and that it is committed to transform its "portfolio" (by which, she means, I think, its product line) in a way that is audited by the Robert Wood Johnson Foundation. The latest development on this front is reported by HealthLeaders Media, which says that 20 doctors from Contra Costa Health Services in Martinez, Calif., have quit the American Academy of Family Physicians in protest of the AAFP's deal with Coca-Cola to develop "consumer education content about beverage sweeteners and other health topics." As the HealthLeaders Media dispatch suggests, there's a kind of cultural shift under way in which Coke and Pepsi seem to be headed the way of tobacco or alcohol or McDonald's meals as a product that, while still legal, is subject to all sorts of sin taxes and advertising restrictions. It's not necessarily because these beverages are more dangerous than other foods, such as, say, butter croissants or ice cream sundaes, but just that they've all of a sudden become unpopular. One wonders what this will mean for the Coca-Cola stake held by Warren Buffett's Berkshire Hathaway.