“Oh, you’re just talking silly talk,” an unseen critic periodically puts in. It’s a delightful children’s read, but these days it’s a little worrisome, too. The fact is that many American kids today—if not quite convinced that rain makes applesauce—come pretty close.

Many kids have no idea where their food comes from or even, in some cases, what it is. In an excerpt from Jamie Oliver’s popular Food Revolution (half TV show, half healthy-food movement), Oliver visits a class of six-year-olds in Huntington, West Virginia, a city with the depressing reputation of being the unhealthiest in America, with an adult obesity rate of nearly 50 percent. He holds up a bunch of ripe tomatoes and asks if anyone knows what