High U.S. obesity rates have prompted calls for a tax on caloric sweetened beverages. Faced with such a tax, consumers are likely to substitute nontaxed beverages, such as bottled water, juice, and milk. A tax that increases the price of caloric sweetened beverages by 20 percent could cause an average reduction of 3.8 pounds of body weight over a year for adults and 4.5 pounds for children.