Accounting for Taste

For early humans, the entire world was a supermarket stocked with seasonal fare. Each forest crawled with potential edibles, each thicket offered a buffet. But alas, this open-air store was void of nutritional labels and the protection of the FDA.

People could only rely on instinct and harsh experience to guide them. Ripe fruit was safe and also packed with vitamins, and so our ancestors developed a preference for sweet foods over the years. At the same time, they evolved an aversion to bitterness, since natural poisons are bitter. Those who avoided such flavors were less likely to eat something toxic and die.

The legacy of the ancient food environment survives to this day. Babies are still born with a love of sugary foods like cookies and a dislike of bitter substances such as coffee. Most people crave fatty fare, which was scarce in the old days (and all too prevalent now). But beyond such general patterns, there are surprisingly few universals when it comes to the human diet. Some of us love tomatoes, or hot peppers, or stinky cheese, while others cannot abide them. When it comes to eating, "the larger problem of accounting for preferences is an area of considerable ignorance," says Paul Rozin, a psychologist at the University of Pennsylvania. But researchers are now beginning to understand the complicated stew of genes and environment that helps determine our favorite—and least favorite—foods.

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1: Picky Palates

Three decades ago, when Marla Lopez was out to dinner with the man who is now her husband, she announced her order: two dinner rolls, two orders of toast, an English muffin, and a croissant. Lopez told the incredulous waitress that she was on the "bread diet." Soon after, the other waitresses in the restaurant descended on slender Lopez's table, wanting to know all about this intriguing plan.

But Lopez, a 51-year-old Realtor in Idaho, wasn't cutting calories. She is an extremely picky eater. She doesn't like steak ("It's like biting the sole of a shoe," she says), or chicken, or any kind of meat—with the exception of very crisp bacon. She doesn't like fruit or vegetables, either. Breakfast is plain Cheerios or cornflakes with just a touch of milk. Lunch is often French fries and dinner might be a plain tortilla, a dinner roll, and a big glass of milk. "You can put pizza, a hamburger, a hot dog, escargot, and dog poop on a plate and I'd have a hard time picking which one I'd rather eat," she says. "To me, they're all gross."

Picky eating is common in children, who naturally exhibit food neophobia, or a reluctance to try new meals. "In the course of things, with repeated exposure, most picky eating in childhood remits," says Marsha Marcus, a psychiatrist at the University of Pittsburgh who is working to register adult picky eaters into a national database for research purposes.

Many of the members of PickyEatingAdults.com, an online support group, report the same aversions as Lopez—fruits, vegetables, and meats. And yet, they almost universally embrace grains and other carbohydrates. "Picky eaters usually dislike bitter and sour, and carbs aren't bitter or sour," explains Elizabeth Capaldi, a psychologist at Arizona State University.

More than flavor, what really seems to bother picky eaters is texture. Although texture is rarely cited as a reason for liking a food, often it is enough to make someone despise it. Many picky eaters are also opinionated about how food is combined and prepared. They might like both peas and rice but refuse to eat the two mixed together.

Where does this behavior come from? Lopez says she has been this way all her life and even gagged on all sorts of common baby foods. "I don't believe it to be a choice," she says. Indeed, a 2007 study of European twins found that food neophobia was strongly heritable.

In fact, a combination of genetic tendencies could be at work. Certain aspects of picky eating resemble known disorders—the concern with texture could be a sign of a sensory processing disorder, for instance, while a distaste for foods that mix or touch could be a manifestation of an anxious or obsessive streak. Picky eaters do score higher than others on tests of anxiety.

The behavior could also be linked to natural human variation in the taste system. Among a group of caucasians studied in the U.S., about 30 percent qualified as nontasters, who are unable to detect bitter compounds. Among the remaining 70 percent, a small subset had a mutation that makes them extremely sensitive to such tastes. These so-called "supertasters" may find the bitterness present in vegetables—and other compounds, such as cheeses and coffee—to be so extreme that they just can't stomach them.

Family environment may also play a role—or at least make picky eating worse. "Forcing children to eat something, or having them eat it in order to get dessert, or making them sit at the table until they eat something they don't like, will make them dislike the food in question even more," Capaldi says. Repeated exposure to new foods doesn't seem to help extremely picky adult eaters, Marcus says. Perhaps they're ultrasensitive, requiring more exposures than most of us. Or perhaps their visceral responses are so strong that they can't even get new foods in their mouths.

By age 30, Lopez (who is currently still slender and without health problems) had managed to add a few things—cheese and mashed potatoes—to her diet. But it's been a lifelong struggle. "When I was in sixth grade," she recalled, "my dad said, 'You eat six new foods and I'll buy you a horse.' I tried hot dogs, orange juice, and that was it. I couldn't get to three, four, five, and six."

2: Adventurous Gourmets

Durian. Stinky tofu. Insects. Jellyfish. Chicken feet. Blood sausage. These strange and unpopular foods—at least, among most Americans—were all on the menu when friends Andrew Abbott and Che Salazar, both 23, cofounded the Boston Gastronauts, a group devoted to eating "things that definitely don't sound appealing to most people," Abbott says.

Globalization has brought new cuisines and ingredients to our shores, making it possible to get exotic-sounding foods in American markets. "Now you can try anything," Rozin says. Meanwhile, television shows are exposing Americans to an ever-widening array of foods—consider, for instance, Anthony

Bourdain's No Reservations, in which he travels the globe eating international delicacies. In some circles, eating strange foods even carries a certain cachet, signaling sophistication. (The Boston Gastronauts is not the only club of its kind—there are adventurous eating clubs popping up all over the nation, as well as special events devoted, for instance, to bug-eating.)

But not everyone is partaking in the foodie revolution.

Particular environments, it seems, help foster adventurous eaters. Children learn a lot through observation, and when they see their parents and family members eating—and enjoying—a wide variety of foods, they're more likely to enjoy these tastes themselves. Research has repeatedly demonstrated this modeling effect, showing that kids are more likely to choose foods that they have witnessed others relishing. "You like things that you see other people liking," says Alexandra Logue, a psychologist and executive vice chancellor and university provost of the City University of New York. "Preferences are affected by what we see on the faces of other people."

Indeed, Salazar attributes his love of exotic cuisines, in part, to his upbringing. His mother is Jewish and his father is Mexican-American, and he grew up eating dishes common to both cultures. His parents are also both caterers—and they cook from a variety of ethnic and national traditions. "Food was so important to my household," he says. Abbott's mother was a caterer, too. "She was always making new things," he says. "I've always been willing to try new things, at least once."

Parents can set up their kids to be broad eaters before they're even born. The smell and taste of a pregnant woman's amniotic fluid reflects the food she eats. "The sensory system is sufficiently mature by the last trimester of pregnancy that the fetus can taste and it can smell," says Gary Beauchamp, a biopsychologist and the director of the Monell Chemical Senses Center. Babies can also detect certain flavors in their mothers' breast milk. In one study, Beauchamp and his colleagues randomly assigned some mothers to drink carrot juice while pregnant or breast-feeding. These moms' kids were significantly more likely to eat carrots as they got older than the children of mothers who hadn't been assigned to drink the vegetable juice.

But modeling and priming don't entirely explain adventurous eating. For one thing, Salazar and Abbott don't always like the strange foods they seek out; Salazar couldn't take more than a few bites of his stinky tofu and wasn't too fond of quail eggs, either. Indeed, what may be most important, then, is having a personality that embraces new experiences. Some research has, in fact, linked eating habits with a trait known as sensation-seeking. Sensation-seekers love stimulation—they tend to be thrill-seekers and risk-takers—and, it turns out, they're more likely to try novel foods. "Some babies are more interested in stimulation from new things than are other little children and that applies to food as well," Logue says.

Such people may also prefer different kinds of foods. In her own research, Logue discovered that people who scored high on tests of sensation seeking reported a greater preference for spicy foods, while low scorers were more likely to prefer bland and sweet food. The high-sensation seekers also seemed to be willing to take more food risks. "Foods that are likely to make you sick, like alcohol and shellfish, were also preferred by people high on sensation-seeking," Logue says. And a 2004 study found that children who like intensely sour flavors tend to like other intense stimuli as well, such as bright colors.

Indeed, though the foods Salazar has explored with the Gastronauts have not always been hits, what really drives him, he says, is "the thrill of trying something new, something I've never tasted before."

3: Reformed And Regimented

A complete diet overhaul, while hard to execute, is appealing, for many different reasons: the promise of better health and vitality, a fascination with structure and control, or even a distinctly unhealthy preoccupation with weight and appearance.

Cory Head, a 30-year-old psychologist in New York, had a pretty unremarkable diet just six months ago. She'd have cereal, fruit, and yogurt for breakfast and a turkey and cheese sandwich for lunch. She ate pasta, soup, and frozen meals, plus pudding and cookies to satisfy her pronounced sweet tooth. But an autoimmune disease was leaving her tired all the time. A friend on a raw-food vegan diet suggested it might give Head more energy. So she decided to embrace it.

Several months into the diet, Head eats no meat, no animal products whatsoever (including dairy and eggs), and nothing that is cooked. She starts her days with a green smoothie—fruit blended with kale or spinach. Her other meals might be a salad or a homemade raw vegan "pizza." For dessert, she's been known to make a chocolate "mousse" out of avocado and cacao powder. And she says she does feel less lethargic.

Head's not the only one who's discovered raw and vegan diets, which fit right into our milieu, Rozin says. "We have as a culture an obsession with immortality and the idea that if you eat a healthy diet and keep bad things out of your diet, you'll live forever," he says.

Though people may adopt such restricted diets for health reasons, this style of eating can, in fact, lead to changes in the way food tastes. Head made a conscious decision to try a new diet—she was interested in its reputed health benefits—and at first, she went through a withdrawal of sorts. "At the beginning I really craved pasta," she says. "I think that's one of the things you can't really replace. I really missed ice cream." She even dreamt of popcorn.

But slowly, she began to adapt. When Head started her new diet, her apartment was still stocked with some taboo foods. One day she gave in to her cravings and had one of the ice cream sandwiches left in her freezer. It did not taste as she remembered. "I didn't like it at all," she says. It suddenly seemed overly sweet, overly artificial. She had the same experience with some leftover jarred applesauce.

People diagnosed with diabetes, for instance, have to drastically cut back on sugar. Beauchamp recalls a study where, after a few months on a low-sugar diet, diabetics reported that fruit tasted sweeter than it ever had before.

Researchers have demonstrated this same phenomenon with salt. In a classic 1982 study, Beauchamp and his colleagues placed some of their young adult subjects on a low-sodium diet for five months. Over the course of the five months, those on a low-sodium diet preferred less salty soups than they had at the start. (The same principle holds true in reverse—the more we eat a certain food or flavor, the more our taste buds get used to it.) Save for the pickiest eaters, it is possible to change one's tastes.

Of course, there's a darker side to disciplined eating; if someone gets overly obsessed, a restrictive diet can shade into disordered eating. (Some studies have found that symptoms of eating disorders are more prevalent among vegetarians.) In fact, some experts have begun using the term "orthorexia nervosa" to describe an eating disorder in which people are overly fixated on eating only "pure" or "healthy" food.

That doesn't mean that all, or even most, vegans or raw foodists are verging on the edge of eating disorders. Many are perfectly healthy, Marcus says. But some people "who think that they're eating for health get fixated and rule-bound, in a way that most of us wouldn't," she says.

But this is all new territory for researchers. "It's important to emphasize that this is an area of inquiry that is just starting," Marcus says. "What is the fine line between eating for good health and a disturbance?"

Palate Makeover

How to acquire better tastes (and encourage them in others).

  • Be patient and persistent: Studies have shown that children may require as many as 15 exposures to new food in order to accept it. And yet, many parents give up before then, offering it no more than five times.
  • Mix an abhorred food with a preferred one: "You can make yourself like vegetables more by mixing them with sugar for a while," Elizabeth Capaldi says.  "Just enough so it cuts the bitter." As you get used to, say, broccoli, you can slowly reduce the amount of sugar until you're eating the vegetable plain. (If you're not convinced, consider that many people add sweeteners to coffee and alcohol when they first start drinking them.)
  • Educate yourself: The more you know about nutrition, the more motivated you'll be to expand your horizons. If you stick with it, Capaldi says, "Your taste buds will come to appreciate stuff that's really good for you."

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