The US fast-food industry spent $4.6 billion last year advertising mostly unhealthy products, with children and teens its key audiences, researchers say. Marlene Schwartz, director of the Rudd Center for Food Policy & Obesity at Yale University in New Haven, Conn., says the center's Fast Food FACTS 2013 report highlights a few positive changes since its 2010 report, such as healthier sides and beverages in most restaurants' kids' meals, but also shows restaurants fall far short of offering only healthier fast-food options to kids.Using the same methods they employed two years ago, researchers examined 18 of the top U.S. fast-food restaurants and documented changes in the nutritional quality of menu items, along with changes in marketing to children and teens on TV, the Internet, social media and mobile devices. The report says: Children ages 6-11 saw 10 percent fewer TV ads for fast-food, but children and teens continued to see three to five fast-food ads on television every day. Healthier kids' meals were advertised by a few restaurants. They represent one-quarter of fast-food ads viewed by children. Less than 1 percent of kids' meals combinations at restaurants meet nutrition standards recommended by experts, and just 3 percent meet the industry's own Children's Food and Beverage Advertising Initiative and Kids LiveWell nutrition standards. Spanish-language advertising to Hispanic preschoolers, a population at high risk for obesity, increased by 16 percent. Fast-food marketing via social media and mobile devices grew exponentially.