What is the theme in Fast Food Nation by Eric Schlosser?

Fast dood being unhealthy and dangerous is the main theme of the book. Americans can no longer ignore the multiple health hazards of a fast food diet. With the advent of fast food chains following World War II, Americans have latched on to the ease and convenience of ordering a meal which is ready within minutes and which, because of advertising and gimmicks, is especially popular with children. The all-American meal is now a hamburger, fries and a Coke, available at any number of chains, or tacos, delivered pizza, and fried chicken, all within a few miles of home. Fat content of these meals is horrendous, not to mention the dangerous amounts of sugar in the sodas which we consume daily.