How does saliva work? Why doesn't your stomach digest itself? And did constipation really kill Elvis? In her new book "Gulp: Adventures on the Alimentary Canal," Mary Roach chronicles the surprisingly exciting journey that food undertakes in the human body. Roach joins us to talk about everything you ever wanted to know -- or might be disgusted to know -- about the digestive process.
Mary Roach's Adventures in Digestion
Mary Roach, author of "Gulp" and other books including "Stiff," "Spook," "Bonk" and "Packing for Mars"