Americans now spend more money on fast food than on higher education, personal computers, computer software, or new cars. They spend more on fast food than on movies, books, magazines, newspapers, videos, and recorded music - combined.
Schlosser describes the growth of the fast food industry as being driven by fundamental changes in American society. From the 1970s onwards, with a steady decline in the hourly wage (adjusted for inflation) of the average US worker, more and more American mothers were working outside the home. In 1975, about 1/3 of US mothers with young children did this. Today, almost 2/3 of such mothers are employed. A generation ago, three-quarters of the money used to buy food in the US was spent to prepare meals at home. Today, about half of that money used to buy food is spent in restaurants - mainly fast food restaurants (in 1968, McDonald's had 1,000 restaurants; today it has about 30,000, and 2,000 new ones each year).
http://www.nytimes.com/books/first/s/schlosser-fast.html