What do households on food stamps buy at the grocery store? The answer was largely a mystery until now. The United States Department of Agriculture, which oversees the $74 billion food stamp program called SNAP, has published a detailed report that provides a glimpse into the shopping cart of the typical household that receives food stamps. The findings show that the No. 1 purchases by SNAP households are soft drinks, which accounted for 5 percent of the dollars they spent on food. The category of ‘sweetened beverages,’ which includes fruit juices, energy drinks and sweetened teas, accounted for almost 10 percent of the dollars they spent on food. “In this sense, SNAP is a multibillion-dollar taxpayer subsidy of the soda industry,” said Marion Nestle, a professor of nutrition, food studies…