A U.S. company that supplies meat to some fast-food chains in China has pulled all of its products, some of which were chicken nuggets sold in Hong Kong, made by a Chinese subsidiary. Kin Cheung/AP hide caption

itoggle caption Kin Cheung/AP

McDonald's was the featured sponsor of the annual meeting of the California Dietetic Association in 2014. Alan Broadhead/Flickr hide caption

itoggle caption Alan Broadhead/Flickr

Fast-food workers march toward the Smithsonian's National Air and Space Museum in Washington, D.C., on Thursday. Similar rallies occurred in about 100 cities across the U.S. Morgan Walker/NPR hide caption

itoggle caption Morgan Walker/NPR