Actually, the government itself does not really do anything to fight fast food. Why would they?
"In 1970, Americans spent about $6 billion on fast food; in 2000, they spent more than $110 billion. 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."
It's a question of money.
Enjoy your chick food.