Mary Roach's Inside View - NYTimes.com Mary Roach's new book, "Gulp," induces both belly laughs and the occasional gag reflex as it explores what happens to food as it passes through a person's alimentary canal. We asked the 54-year-old author of "Stiff" and "Bonk," who lives in the Bay Area, about the bites and sips that take the fantastic voyage past her mischievous grin. How to relish a cocktail by breathing "I discovered that we have internal nostrils. I like gin. So when I have gin in my mouth, I'll do this thing - this is since the book. It's called retronasal olfaction, where you're sniffing by exhaling, and you're wafting the gases in your mouth up into your nasal cavity. An early fondness for gin "I've liked gin since actually I was a small child, because my dad was British, O.K., and he drank a lot. For a while, his drink was the martini, before he switched to Scotch. When I was a kid, in fourth grade maybe, my dad would always give me one of the olives - or the olive. Back then they'd only give you one. How she savors an oyster "My idea of a great splurge is Swan Oyster Depot on Polk Street in San Francisco, which is only open during the day. A great selection of oysters from Tomales Bay - very fresh, really fantastic. There'll be a half-dozen different varieties that they'll have, and they'll throw them on a platter for you. And white clam chowder that's not gluey. It's not supposed to be gluey. You're not supposed to stand a spoon up in it. It's really great clam chowder, with sourdough and Anchor Steam on tap. I'm an oyster chewer. But there are people who just swallow. I like to chew. You release all the flavors, and the sweet after-finish - you're not going to get that if you just swallow it down like a pill. The food she was raised on "I grew up in New Hampshire, and I spent all my time over at the neighbors." It's frightening, the number of Vienna sausages and Slim Jims that I ate as a kid. I was raised on the 100 percent processed food diet. My mom was Catholic, so Friday was Mrs. Paul's fish sticks. We had canned ravioli - Ravioli O's. Swanson TV dinners - my brother had shrimp, I would get turkey. How that affected her body "I wonder if I'm going to be dead in 10 years. It seems like it must have had some lasting negative impact. Because I read about various findings on processed food - you name it, I ate the worst of it. The salt content in that stuff? Unbelievable. I mean, I pickled my insides for 18 years. And I don't know how it's going to play out. I do think I'll get cancer. How working on the book made her focus on the food in her mouth "I did have a period of time where I purposefully wanted to pay attention to what's called bolus formation. It's kind of important to get it right, and nobody really thinks about it. Because you don't have to. You're not supposed to think about it. What's actually going on in there when you take a bite "You chew. And then you've got your tongue and your cheeks and everything, and you're rolling it around, and you're like a sushi chef: You know, those guys pick up the rice, and they go" - she pantomimes a hand motion of squeezing and scrunching - "and it's this magic thing. They open their hand, and there's the rice bolus. They're doing a hand bolus, that's what they're doing. You want to be doing that. In your mouth. And then you position it. You've got to position it. And then you go to swallow it. And this is what I love - there's like a metering light in there. You know, a metering light holds the traffic back for a second? There's that, so that your body has time to rearrange the larynx, get ready for the swallow. When it all goes right, it's a beautiful ballet that's happening. But I tried to pay attention to it, for a while, and it's very hard to do. It very much detracts from the enjoyment of eating. Some say it's better for you to masticate your food thoroughly, even counting the number of chews "Your stomach does a perfectly good job of reducing what you put in there to liquid. With the exception of, like, peanuts and corn - your marker foods. Your marker foods travel all the way through. This interview has been condensed and edited.