New York City--Investors looking to beef up their portfolios as the economy recovers will likely see only modest gains from the top three burger makers in 2002. Indeed, this could be a lean year for McDonald's, Burger King and Wendy's, the chains that account for 75 percent of the more than $45 billion Americans spend every year at fast-food burger joints. Factors impacting the financial performance of these chains include the increasing popularity of fast-casual restaurants and weak international economies. Analysts, though, believe these are only short-term challenges for the companies to overcome. -Business Week