WASHINGTON (AP) — Wondering how many calories are in that hamburger? Chain restaurants still don't have to tell you, despite a 6-year-old law requiring calorie labels on menus. Passed as part of the health care overhaul in 2010, the rules will eventually require restaurants and other establishments that sell prepared foods and have 20 or more locations to post the calorie content of food "clearly and conspicuously" on their menus, menu boards and displays.