Some of your favorite foods — sushi, extra virgin olive oil, Kobe beef, Parmesan cheese — may not be what you think they are. How can you get a handle on what you eat and where it came from? USA Today columnist Larry Olmsted explains in his new book, Real Food/Fake Food: Why You Don’t Know What You’re Eating and What You Can Do About It . Olmsted recently spoke with the Knowledge at Wharton Show on Sirius XM channel 111 about his book. An edited transcript of the conversation follows. Knowledge at Wharton: It was recently discovered and reported that much of the Parmesan cheese sold here in the United States had some level of wood pulp in it. Your book takes an in-depth look at many of the problems out there right now. What are the best foods out there that give us the best nutrition and are tasty as well? Olmsted: You mentioned the Parmesan cheese, the wood pulp thing. I’ll just start there as an example. I’ve been to Parma, Italy, where the real thing is made. That’s why it’s called Parmesan cheese.…