Gulp

It’s no coincidence that the word “visceral” refers both to entrails and to the sensation one feels on a roller coaster. We humans have a love-hate relationship with our guts, and Roach’s latest book capitalizes on that mix of fascination and repulsion to lure us into reading about the digestive system.

Gulp explores the alimentary canal, moving like a bolus of food from mouth to stomach to lower gastrointestinal tract. Along the way, Roach visits scientists studying the various elements of eating, digesting and eliminating.

Roach has an eye for the odd. Rather than write a treatise on the properties of stomach acid, for instance, she tells the story of surgeon William Beaumont and his career studying the fistulated stomach of Alexis St. Martin. An 1822 shooting accident left St. Martin with a fistula, or hole, through which the doctor could slip pieces of food and study their digestion. The rest of the book proceeds with similarly quirky research on saliva, chewing, gut bacteria and more.

Like her four previous books, Gulp is a whirlwind tour. Luckily, Roach makes you feel as if you’re on the tour bus with your funniest friend providing running color commentary. She’s completely fearless, perfectly happy to plunge her hand — nay, her entire arm — into a cow’s stomach to feel its digestive caress. The next thing you know, she’s off to a lab where she hopes a researcher “might be able to whip up a batch of artificial flatus.”

Some may say it’s all a bit silly, but Roach embraces the puerile attraction of her topic. “I don’t want you to say, ‘This is gross,’ ” she writes. “I want you to say, ‘I thought this would be gross, but it’s really interesting.’ ” And it is. — Erika Engelhaupt

W.W. Norton & Co., 2013, 348 p., $26.95