Pull open the glass door and feel the rush of cool air. Step inside. Look at the backlit color pictures of food above the counter, look at the cardboard ads for the latest Disney movie, get in line, and place your order. Hand over some money. Put the change back in your pocket. Watch teenagers in blue-and- gold uniforms busy working in the kitchen. Moments later, grab the plastic tray with your food, find an empty table, and sit down. Unwrap the burger, squirt ketchup on the fries, stick the plastic straw through the hole in the lid of your drink. Pick up the burger and dig in.

The whole experience of eating at a fast-food restaurant has become so familiar, so routine, that we take it for granted. It has become just another habit, like brushing your teeth before bed. We do it without even thinking about it—and that’s the problem.

Every day about one out of fourteen Americans eats at a McDonald’s. Every month about nine out of ten American children visit one. McDonald’s has become the most popular fast-food chain in the world—and by far the most powerful.

In 1968 there were about 1,000 McDonald’s restaurants, all of them in the United States. Now there are more than 31,000 McDonald’s, selling Happy Meals in 120 countries, from Istanbul, Turkey, to Papeete, Tahiti. In the United States, McDonald’s buys more processed beef, chicken, pork, apples, and potatoes than any other company. It spends more money on advertising and marketing than any other company that sells food. As a result, it is America’s most famous food brand. The impact of McDonald’s on the way we live today is truly mind-boggling. The Golden Arches are now more widely recognized than the Christian cross.

Despite McDonald’s fame and all the money it spends on advertising, every day the vast majority of its customers don’t plan to eat there. Most fast-food visits are impulsive. The decision to buy fast food is usually made at the last minute, without much thought. People generally don’t leave the house in the morning saying, “I’m going to make sure to eat some fast food today.” Most of the time, they’re just walking down the sidewalk or driving down the road, not thinking about anything in particular. Maybe they’re hungry; maybe they’re not. Maybe they’re in a hurry and don’t have time to cook. And then they see a great big fast-food sign—the Golden Arches, the red-and-blue of a Domino’s pizza box, the picture of Colonel Sanders—and they suddenly think, “Hey, I want some of that.” So they stop to eat fast food. They do it because they feel like it. They just can’t resist the impulse.

The point of this book is to take that strong impulse we all feel— our hunger for sweet, salty, fatty fast foods—and make you think about it. Chew On This will tell you where fast food comes from, who makes it, what’s in it, and what happens when you eat it. This is a book about fast food and the world it has made.

Food is one of the most important things you’ll ever buy. And yet most people never bother to think about their food and where it comes from. People spend a lot more time worrying about what kind of blue jeans to wear, what kind of video games to play, what kind of computers to buy. They compare the different models and styles, they talk to friends about the various options, they read as much as they can before making a choice. But those purchases don’t really matter. When you get tired of old blue jeans, video games, and computers, you can just give them away or throw them out.

The food you eat enters your body and literally becomes part of you. It helps determine whether you’ll be short or tall, weak or strong, thin or fat. It helps determine whether you will enjoy a long, healthy life or die young. Food is of fundamental importance. So why is it that most people don’t think about fast food and don’t know much about it?

CHEW ON THIS: EVERYTHING YOU DON’T WANT TO KNOW ABOUT FAST FOOD by Eric Schlosser and Charles Wilson. Copyright (c) 2006 by Eric Schlosser. Reprinted by permission of Houghton Mifflin Company. All rights reserved.