In a move affecting the cooking of more than 6 million pounds of french fries a year, Marriott International is eliminating frying oil containing trans fats from its more than 2,300 hotels in the United States and Canada. [...] For decades, restaurants have been using vegetable oils that have gone through a process called hydrogenation, which increases shelf life but produces trans fats. The new oils are made with genetically modified soybean oil that contains lower levels of an acid that reduces shelf life.