Fast food chain McDonalds has announced that it will now post calorie information on all its menus from Monday. We want to voluntarily do this, said Jan Fields,president of McDonald''s USA. "We believe it will help educate customers, Fields added. According to CBS News,the move by the worlds biggest burger chain cloud put pressure on other major restaurants to post the information next to all their foods. The decision to post calorie information follows a US courts decision to uphold President Barack Obama''s health care overhaul,which includes a regulation that would require restaurant chains with over 20 locations to post calorie information. According to experts,posting of calorie information is no magic bullet in fighting obesity,but could have a big effect over time. Obesity isn''t the kind of thing where one day you wake up and you''re fat. We gradually and slowly gain weight over time, Margo Wootan,director of nutrition at the Center for Science in the Public Interest,said.