CHICAGO (Reuters) - The Food & Drug Administration will no longer require companies that sell snacks and other foods containing the controversial fat substitute olestra to warn that it can cause cramping and other digestive problems. In a ruling Friday, the FDA eliminated that requirement, which has been in warning labels ever since 1996, when the agency allowed Procter & Gamble Co. to market the fat substitute, which is sold under the brand name Olean. The decision comes after an FDA review of new scientific data, including clinical studies of people eating olestra, a substance made from soybeans and sugar,...