** FILE ** As part of first lady Michelle Obama's nationwide campaign to lower childhood obesity rates, Wal-Mart and other retailers plan over the next five years to open or expand 1,500 stores in areas without easy access to fresh produce and other healthy foods. "This is a really big deal," Mrs. Obama said. (Associated Press)

** FILE ** As part of first lady Michelle Obama's nationwide campaign to lower childhood obesity rates, Wal-Mart and other retailers plan over the next five years to open or expand 1,500 stores in areas without easy access to fresh produce and other healthy foods. "This is a really big deal," Mrs. Obama said. (Associated Press)