Mary Roach passes through town to talk about Gulp

“It sounds so leisurely,” Mary Roach says. “Like sailing down the Danube – a picturesque adventure.”

The journey she’s telling me about isn’t a river cruise, though, but a float trip down the alimentary canal. That’s the subject of the author’s most recent book, Gulp, newly issued in softcover.

It’s the word canal that causes confusion, she says. That anatomical passage is a canal only in the most, you know, romantic sense. It’s really more of a fleshy tube that extends from your mouth to your anus and functions in the digestion and absorption of food and the elimination of waste.

Just what happens along the alimentary canal is one of the adventures in fascinating (and occasionally gruesome) bodily functions that Roach traces in Gulp. Roach discusses the book – and the research behind its often hilarious anecdotes – at 6:30 p.m. Thursday, April 24, at the Kansas City Central Library (14 West 10th Street, 816-701-3400).
Food, of course, is a primary passenger along the route, so Roach covers a range of culinary mysteries and answers some burning questions. Why is crunchy food so appealing? How much can you eat until your stomach bursts? Can constipation kill you? In fact, it’s just this kind of potentially embarrassing material that put Roach on the canal. She had gathered more research than you’d imagine possible for a magazine article about flatulence – or, more to the point, Beano, the over-the-counter enzyme that, the label assures you, “helps prevent gas before it starts.”

“I had a lot of wonderful material that I didn’t use in the article,” Roach says. “I had it sitting in a file, and I thought, I could do something with this. So I did.”

Roach’s Beano investigation makes up one of Gulp’s livelier chapters, “Dead Man’s Bloat,” in which she discusses the gas she produced – thanks to a hearty meal of chili – for a 1995 flatulence study.

That tale is somewhat less ghastly (and way funnier) than Roach’s account of a 1968 nutritional sciences study held at the Berkeley campus of the University of California. Six young men there were sequestered in a metabolic chamber for two days, eating meals created for them from dead bacteria.

“All of the subjects became very ill,” Roach says. “We’re talking vomiting, vertigo, nonstop bowel movements. They were being fed something described as a slimy slurry of aerobacter.”

Shocker: It didn’t taste good. Which is the one way the body warns you not to take chances with slurry. There’s also smell, which heavily influences how we taste.

“The tongue is much less important than the nose in terms of taste,” Roach says. “Did you know that we have two sets of interior nostrils? We can perceive five tastes – sweet, bitter, salty, sour and umami [a brothy sensation] – but an almost infinite number of smells. When you chew food or sip wine, gases are released, and as you exhale, these volatiles waft up through the nostrils.”

Another discovery for Roach was the importance of tooth sensitivity to the dining experience: “We think of our teeth as these blunt, dumb mallets, but they’re actually exquisitely sensitive.”

Roach says her book might make a fascinating animated film. (“The book trailer online is animated,” she says. “With puppets!”). And certainly it does for the human digestive system what Raquel Welch and Stephen Boyd did for the circulatory system in the 1966 sci-fi movie Fantastic Journey.

But the science in Gulp would stand Welch’s hair on end. Still, Roach’s sense of humor keeps the journey from mouth to anus a mostly upbeat affair.

“I try not to be a downer,” she says.