The externalites aren't priced in though. Heavy consumers of soft drinks require more health care on average which affects insurance prices of non-drinkers. To

The externalites aren't priced in though. Heavy consumers of soft drinks require more health care on average which affects insurance prices of non-drinkers. To be truly "fair" this should be factored into the price of such products so that buying a coke includes an x dollar tax for your estimated increase in medical needs. This is however only doable with a socialized medical system. The other option is to let insurance companies monitor your diet, but that sounds quite a bit more dystopic...