Most patrons of fast-food shops are regularly asked if they'd like to "value size" or increase the portions of their meal for a few cents more.
Experts say supersized meals and a "clean plate" culture largely contribute to a national obesity rate among adults greater than 33 percent.
But for a few weeks at a time in 2010, visitors to the Panda Express franchise at Duke University in Durham, N.C., were offered the option of less -- and a surprising number of people took it.











