There was a great special on PBS a couple years ago called "People Like Us" that explored how social class impacts our lives.
One of the segments, based on the social implications of white bread and wheat bread, featured a battle over a co-op in Burlington, VT. In this case a co-op had replaced a local chain grocery store. The poorer members of society were all up in arms because they could not buy white bread at the co-op even though the co-op offered loaves of organic wheat bread for less than a dollar.
The segment also went to a local food bank where they were unable to give away loaves of really expensive fresh-baked organic bread but quickly ran out of cheap processed white bread.
Basically the segment was arguing that poorer, working-class Americans view food as a status symbol. In this case organic wheat bread is the food of wealthy, bohemian liberals (Bobos) and the lower classes want nothing to do with it because it is incongruous to their social class.
The same could be said for espresso, non-iceburg lettuce, and pretty much all ethnic foods besides italian and chinese.
