Have you ever wondered why humans prefer crunchy foods rather than mushy ones? How do competitive eaters train to eat 36 hot dogs and is it possible for you to eat yourself to death? Is there any truth to reports that a superworm can survive in a bullfrog’s gut after it’s been swallowed? And how did Elvis die—from a drug overdose or chronic constipation?
These are just some of the subjects explored by best-selling author Mary Roach ’81 in her latest book, Gulp: Adventures on the Alimentary Canal (W. W. Norton), yet another entertaining and well-researched foray into strange realms of science that other writers might avoid. Roach has gained a loyal following over the years with her books covering the scientific study of dead bodies (Stiff), the afterlife (Spook), sexual physiology (Bonk), and space travel (Packing for Mars), and now she tackles the digestive system with her usual sense of wonder and fun.
In the introduction Roach points out, “When it comes to literature about eating, science has been a little hard to hear among the clamor of cuisine.” Though she admires writings about the art of dining, by authors such as M. F. K. Fisher and Calvin Trillin, she is much more intrigued by the science of what happens to food in the human body after we eat it and with the “delightful, unusual people who study it.”
When she wrote her last book, Packing for Mars, Roach examined the bodily experiences of astronauts and did not turn away from their eating, digestive, and excremental habits. In Gulp, she focuses on the entire digestive process—what happens to food once it enters the body, progressing through tasting and chewing to swallowing, digesting, and excreting—and takes us to several unexpected places along the way.
“Feeding, and even more so its unsavory correlates, are as much taboos as mating and death,” she writes. “The taboos have worked in my favor. The alimentary recesses hide a lode of unusual stories, mostly unmined. Authors have profiled the brain, the heart, the eyes, the skin, the penis and the female geography, even the hair, but never the gut. The pie hole and food chute are mine.”
In her New York Times review, Janet Maslin says, “Gulp is far and away her funniest and most sparkling book, bringing Ms. Roach’s love of weird science to material that could not have more everyday relevance.” Last spring the book debuted on The New York Times nonfiction Best Sellers list at number two.
Roach has appeared twice on The Daily Show with Jon Stewart, and when she appeared on the program last April to talk about Gulp, the host opened the interview by saying enthusiastically, “I like your books! Very funny!” When Stewart and Roach talk together, it becomes obvious that they connect in their appreciation of word play.
“Whenever I hear that I’m going on the show, I get very excited,” Roach says. “Stewart is such a lovely person. He comes in and talks to you while you’re having your makeup done and puts you at ease. We both share the same love for jargon and surreal scientific terminology. It’s just a glee fest.”
The Seattle Times has written that “Roach is authoritative, endlessly curious and drolly funny. Her research is scrupulous and winningly presented,” and many other publications have echoed this praise. Yet curiously, she did not set out to follow her present career.
“At Wesleyan I had no plans, interest, or intent to become a writer,” she says. “I was one of those wonderful liberal arts students who just thought, ‘I don’t need to think about my career. I’ll just graduate from Wesleyan and the world will drop in my lap.’”
Her time at Wesleyan was a very positive experience.
“I attended a very preppy, sports-oriented public high school,” she says. “I didn’t really fit in. I wasn’t popular. I didn’t get invited to parties. Then I went to Wesleyan and it was like being born. From the day I got there I loved it, I loved everyone and everything about it. It shaped who I am. It was incredibly valuable and important to me for that reason.”
“I came from a small town in New Hampshire where everyone was kind of the same,” she says. “Suddenly I was involved with really interesting, funny, creative, appealing, charismatic people. I felt like I was home. I figured out who I am and that I fit in with this eclectic group of people, where you’re allowed to embrace your individuality.”
Roach didn’t start writing professionally until around 1984, when she did some humor pieces for The San Francisco Examiner. Her first paid writing job came in 1985, when she worked at the public affairs office of the San Francisco Zoo, writing press releases and articles for the membership magazine. She then became a freelance writer for magazines from 1986 through 2000.
One of the first magazines she wrote for was a smart health and medical magazine, Hippocrates, which won a lot of national magazine awards and put her in the position of being coached and encouraged by its editors. During this time, she also wrote pieces for Discover, Vogue, GQ, National Geographic, and The New York Times Book Review. In 2000, she signed the book contract for Stiff with W. W. Norton and her book-writing career was launched.
Reviewers have consistently praised her insightful research on quirky topics and her love of language, but they have also singled out her dry and often wicked sense of humor, a rarity among science writers.
“Humor is important to me but if it doesn’t serve the topic, I don’t push it,” she says. “I gravitate toward material that will enable me to have some fun, but sometimes there is no fun to be had. But I would feel a little out of my element if I took on a topic where there was no room for humor. Still, I don’t consider myself a humorist or a humor writer.”
Gulp took her two-and-a-half years to write. Most of her books present challenges in regard to meeting up with subjects. It was somewhat easier for her to write and complete Gulp because she didn’t have the kind of access problems she had dealing with NASA or with people doing cadaver research, who can be unenthusiastic sometimes about having writers or members of the media visit them. With her latest work, she was surprised that even the people she talked to at a state prison, as well as a surgeon who performs life-saving fecal transplants, were very accommodating.
Roach arrived at the subject matter of Gulp in the same way she has with her other works.
“I don’t really come up with ideas so much as I have a cluster of things I’d like to write about and then I look for an umbrella topic that would encompass them,” she says.
“Some years ago for one of my stories, I went to AkPharma, the company that created Beano, where they do some flatus research. I had a lot of great material, but the editor I had at the time didn’t want to take advantage of it.
“So I had that in the back of my head. I had also been communicating with a gastroenterologist. I remember saying to him, ‘What’s interesting and strange about the intestines?’ And he wrote back, ‘Everything is interesting and strange about the intestines.’ And he gave me some interesting facts, including this notion that the whole GI [gastrointestinal] tract is considered to be something outside of your body. We have this tube going through us where there’s filth and bacteria and decay and all these things that you wouldn’t want in the rest of your body, but it’s all contained in this tube, almost as if it’s outside of the body.
“That was kind of fascinating to me, the notion that the GI tract is like an offshore gambling zone. Other rules apply—it’s a whole other world in there: bacteria, foul odors, feces, saliva. This disgusting stuff is all in this tube. That was an interesting concept to consider, and the GI tract almost became like a travelogue, a visit to this foreign locale that happens to be running through our bodies.”
Writing about the alimentary canal involved dealing with subject matter that some people might find difficult to consider or taboo, but that appealed to Roach.
“I enjoy playing around in taboo topics, not because I want to upset or outrage people, but the opposite,” she says. “People often turn away naturally from particulars of sex, physiology, digestion, or excretion. I want to take people by the hand and bring them to a place that they might think would be upsetting but that in fact is really interesting. You go through your life with this body. How could that not be interesting? So I want, in a way, to encourage people not only to go there but to maybe have a little bit of respect or awe, rather than disgust
Roach begins her story, intriguingly enough, with the nose. In a chapter on tasting, she reveals that this sense relies a lot on smelling.
“The exact verb would be flavoring, if that could be a verb in the same way tasting and smelling are,” she writes. “Flavor is a combination of taste (sensory input from the surface of the tongue) and smell, but mostly it’s the latter. Humans perceive five tastes—sweet, bitter, salty, sour, and umami (brothy)—and an almost infinite number of smells. Eighty to ninety percent of the sensory experience of eating is olfaction.”
Roach introduces us to the first of many fascinating people in her book, Sue Langstaff, a sensory analyst who rides a Harley and evaluates products in the wine and brewing industries: “There are surely many things she enjoys about traveling by motorcycle, but the one Sue Langstaff mentions to me is the way the air, the great and odorous out-of-doors, is shoved into her nose.”
On one of several interesting field trips Roach takes in the book, she accompanies Langstaff to the Olive Center at the University of California, Davis, where the expert has been hired to train a new UC Davis Olive Oil Taste Panel. Roach tries out to be an apprentice olive oil taster but runs into trouble when she is given a test to rank four different olive oils according to bitterness.
“There were no volatile aromas of fresh- mowed grass or lemon or anything that’s going on in the nose,” she says. “To me, they all tasted just exactly the same and none of them tasted particularly bitter. I’m kind of a high-achieving gal, but I just gave up.”
Roach also visits AFB International, a center for testing pet foods that she finds fascinating. She soon discovers that these foods have to satisfy not only their pets but their owners as well.
“There are two things that a pet owner is concerned about,” Roach says. “One of them is ‘Will my pet like this?’ But the other concern is aroma. If the owner opens up the can or spills food from a bag into a bowl and it smells really rank, the pet may love the smell but the owner won’t want to deal with it. So the challenge is to find something that the pet will go crazy for and the owner won’t be repulsed by.”
And though pet foods come in a variety of flavors because that is what their owners like, pets may not like the choices at all. As the AFB vice president tells Roach, for cats in particular “change is often more difficult than monotony.”
“The extent to which Americans project their own food qualms and biases onto their pets has lately veered off into the absurd,” Roach writes. “Some of AFB’s clients have begun marketing 100 percent vegetarian kibble for cats. The cat is what’s called a true carnivore; its natural diet contains no plants.”
In another chapter, Roach journeys to Food Valley in the Netherlands, a group of universities and research facilities of nearly “fifteen thousand scientists dedicated to improving, or depending on your sentiments about processed food, compromising the quality of our meals.” She travels there in part because of her interest in the basics of chewing.
She discovers that teeth and jaws are impressive not for their strength but for their extraordinary sensitivity. Though people think of them as blunt elements of destruction like little mallets, human teeth “can detect a grain of sand or grit ten microns in diameter. A micron is 1/25,000 of an inch.”
Roach meets with Andries van der Bilt, an oral physiologist who has studied the neuromuscular elements of chewing for 25 years and possibly knows more about the subject than anyone else on the planet. He asks her to sample from a bowl of rubbery white cubes made of silicone, which can be used to track “‘masticatory performance’—how effectively a person chews.
“Van der Bilt and his colleagues are dealing with understanding how to help people whose swallowing mechanism is off,” Roach says. “In relation to chewing and swallowing, if you have any kind of disability in that area, you can choke very easily. Children, for instance, have immature swallowing coordination. They don’t have it all down, plus they get their front teeth first, before their back ones, so they can bite something off but not chew it and then may swallow and choke. There’s a lot of safety work that goes on in that oral processing world, but some of it is pure physiology—just understanding what the teeth and tongue and cheeks and lips are all up to.”
It turns out that, for most people, being able to chew properly and swallow is related to the enjoyment of food.
“If you have difficulty swallowing or you have some sort of a stricture from an accident or injury, and you have to be fed with an IV or something else, it’s very depressing because there’s no pleasure or joy associated with eating anymore,” Roach says.
“What one surgeon told me is that when people who have a problem with moving the voice box aside to allow food to go down—that business of moving the equipment around so that the airway closes off and the food tube opens—there are people who say, ‘Just take out my voice box. If it’s not working properly, I want to be able to chew and swallow.’ There are people who would rather be mute than not be able to chew and swallow food.”
During her research, Roach comes across Horace Fletcher, a “self-dubbed economics nutritionist” who lived at the turn of the 20th century and left his letters to Harvard University. Fletcher thought that by “chewing each mouthful of food until it liquefies, the eater could absorb more or less double the amount of vitamins and other nutrients.” He estimated that the United States could save half a million dollars a day by Fletcherizing. Though he had no background in medicine or physiology, he started a fad for extremely thorough chewing that was adopted by generals and presidents, as well as Henry James, Franz Kafka, and Sir Arthur Conan Doyle. Follow-up studies were undertaken by scientists at London’s Royal Society, Cambridge University, and Yale, with mixed conclusions.
In the Netherlands, Roach also meets with Italian-born saliva expert Erika Silletti, whose creamy skin tone, cashmere sweater, and black leather boots might grace the pages of a fashion magazine. Silletti shares her excitement in gathering saliva for study and finds delight in how fast the brain tells the mouth to produce saliva while eating. From Silletti, Roach learns that amylase is the main digestive enzyme in stimulated saliva, breaking down starches, such as bread, into simple sugars useful to the body.
“There’s just a tremendous number of components and processes going on with saliva that people aren’t aware of,” Roach says. “People think of saliva as just a moistening agent or something that is disgusting. When you spit at somebody, that’s the worst possible insult. But the things that most people—including myself when I started the project— aren’t aware of are saliva’s antibacterial and antiviral properties. Also, that the digestive enzymes in saliva that break down starch, protein, and fat are the same enzymes that are in laundry detergent.”
Roach also talks to Michael Levitt, a scientist at the Minneapolis VA Medical Center, who invented the breath hydrogen test, which “originated not as a flatulence assessment technique but to diagnose malabsorption of carbohydrates in the small intestine.” But he is best known as an expert on the secrets of noxious flatus.
“He was the first person to use the technology of gas chromatography to identify the components of intestinal gas,” she says. He found that three sulfur gases were responsible for flatus odor.
Roach is especially curious about the Mylar pantaloons Levitt invented to trap flatus in his study to simulate real-life gas-passing conditions. She asks the scientist if she can see them.
“He doesn’t know where they are stored,” she writes, “but digs out a photograph of a woman … modeling them. Shown uninflated, they fit more snugly than I’d pictured them. The material is silver, crinkly, and reflective. They’re the sort of clothes baked potatoes wear.”
Levitt eventually moved on to the study of hydrogen sulfide, which in extreme concentrations is lethal. But as Roach assures us, the concentration of hydrogen sulfide in offensive human flatus, around 1 to 3 parts per million, is harmless.
Roach takes us unexpectedly to Avenal State Prison in California, where she talks to inmates and guards. We learn that “well over a thousand pounds of tobacco and hundreds of cell phones are rectally smuggled into California state prisons each year,” which the prisoners resell for a lot of money. One inmate she talks to, whom she calls Rodriguez in the book, surprised her by taking the time to give her a very detailed anatomical description of his smuggling talents. She finds Rodriguez a “delightful man” who also happens to be serving life for murder.
“I was curious from an anatomical and physiological perspective how the inmates were able to accomplish what they do,” Roach says. “Here they were using the rectum for storage in an extreme way. I thought that their perspective on the rectum might be both illuminating and entertaining. I know how the rectum works. If you fill it to a certain point, it becomes very hard to hold things in there. You reach a point where you’re triggering stress receptors and can start fighting that urge. You can only do it so long.”
Oddly enough, one of the block captains at the prison tells her about an inmate “caught with two boxes of staples, a pencil sharpener, sharpener blades, and three jumbo binder rings in his rectum. He became know as ‘OD,’ for Office Depot. They never found out what he intended to do with the stuff.”
Roach’s relentless research leads her to examine whether constipation can become life-threatening. It turns out that the death of Elvis Presley provides an answer, and she speaks with Presley’s Memphis doctor, George Nichopoulos, about the singer’s condition of chronic constipation. Some people have thought Presley died from a drug overdose.
“Elvis had a grossly distended nonfunctional colon and might have had a congenital condition called megacolon,” Roach says. “Also, he did a lot of prescription drugs and painkillers and things that slowed down the motility of the gut, so that surely contributed. It may have been a combination of things.
“People with heart conditions in the ICU are put on stool softeners because if you’re pushing too hard from constipation, you can get this response where your heart goes into an arrhythmia that can be fatal. Elvis died on the toilet of fatal arrhythmia, according to his death certificate.”
Roach doesn’t hesitate to become a subject in her own research. After writing so much about the digestive tract, perhaps it isn’t surprising that she decides to have her first colonoscopy without drugs so she can have a look at what’s inside. She knew from speaking to gastroenterologists that the procedure without drugs was often not particularly painful. In Europe and parts of Asia, the procedure is performed with sedation on demand. “It’s ready to go if you ask for it, if you need it,” Roach says. In one recent study, 80 percent of patients didn’t ask for sedation. In America, however, one is rarely given an option.
“It’s interesting to look at how different cultures approach it,” she says. “People don’t have any real reason to think or know that it’s going to be a tremendously painful procedure without drugs if they haven’t tried it.”
Roach admits that if you’re a small person or you have a very kinky, twisted colon, like herself, it can hurt a few times, but it’s not unbearable. She preferred to be able to get up and walk out afterwards under her own steam.
In the book, she describes her experience as revelatory: “There is an unnameable feeling I’ve had maybe ten times in my life. It’s a mix of wonder, privilege, humility. An awe that borders on fear. I’ve felt it in a field of snow on the outskirts of Fairbanks, Alaska, with the northern lights whipping overhead so seemingly close I dropped to my knees. … Laying eyes on my own ileocecal valve, peering into my appendix from within, bearing witness to the magnificent complexity of the human body, I felt, let’s be honest, mild to moderate cramping. But you understand what I’m getting at here. Most of us pass our lives never once laying eyes on our organs, the most precious and amazing things we own. Until something goes wrong, we barely give them thought. This seems strange to me.”
Perhaps more unexpectedly, at the University of California, Davis (the first place she visits for this book), Roach puts her hand inside a cow’s rumen, the largest compartment of its four stomachs, which she describes as “just amazing and very cool.”
“It felt like it was some kind of industrial mixing machine. I was actually concerned that I might break a finger or something. There are very powerful steady motions going on in there like there was an automated mixing paddle because of the contractions.”
“And the cow was utterly bored,” she adds. “I didn’t mean to use the word ‘utterly.’ Extremely bored. Could not be more bored.”
Unlike Roach’s grateful readers, who never lose interest. When they read her books, they could not be more intrigued and entertained by her witty writing and boundless curiosity, hungry for more.