Commentary: Soda taxes, obesity, and the shifty behavior of consumers.

Rising obesity is a threat to public health, and taxing sugar-sweetened beverages (SSBs) in order to reduce consumption and thus caloric intake could be a viable policy response. But raising the price of SSB calories will raise the quantity demanded of relatively cheaper calories, and net effect on obesity is unclear. I review the evidence on shifting calorie demand and discuss the viability of soda taxes to achieve improvements in public health.