Americans consume massive amounts of junk food for many reasons. Junk food tastes good. For many working families it saves time on meal preparation.  There is a temptation on almost every corner and some people do not have the will power to drive by the fast food restaurants and not buy something.  Junk food is cheap.  Some people just don't know what foods they should be eating.  Some people were raised eating junk food so they continue to eat that way.