Taste: Surprising Stories and Science About Why Food Tastes Good (30 page)

How is the level of
tartness
in this chocolate bar?

How is the level of
saltiness
in this chocolate bar?

How is the level of
bitterness
in this chocolate bar?

How is the level of
chocolate aroma
in this chocolate bar?

How is the level of
roasty aroma
in this chocolate bar?

How is the level of
dairy/milky aroma
in this chocolate bar?

How is the level of
fruity aroma
in this chocolate bar?

How
smooth
is the texture of this chocolate bar?

How
waxy
is the texture of this chocolate bar?

How
creamy
is a mouthful of this chocolate bar?

PART 2: PREFERENCE

How much do you
like
this chocolate bar?

Which sample do you prefer?
SAMPLE
: (circle)   A    B
Why?

OBSERVE

1. Compare your ratings with those of your fellow tasters. How do they differ?

2. Why did you like your preferred sample?

3. Do you think this preference extends to other foods and beverages?

M
y friend Sally has two beautiful, healthy, vivacious little blond girls she adores, but anytime her husband starts a discussion about having a third child, Sally immediately quashes his hopes. While she wouldn’t mind a third child, she has her reasons for stopping at two.

“I didn’t enjoy being pregnant,” she says of the unrelenting morning sickness she experienced during both pregnancies. “It was so bad. With Kathryn it lasted five months. With Barrett, my second, it started at seven weeks, lasted the whole pregnancy. It never went away. I threw up, actually, the day I gave birth.”

Even the thought of being pregnant again makes Sally cringe with a visceral physical reaction. “I could never be pregnant again,” she says definitively.

Not surprisingly, Sally had trouble eating while pregnant. The mere sight of some foods, such as raw chicken, would make her vomit. Tomatoes, which she usually loves, would send her running to the bathroom. Her obstetrician put her on the antinausea drug Zofran, which is used to help cancer patients cope with the side effects of chemotherapy.

“It was worse in the early stages,” Sally remembers, “I would throw up throughout the day. Probably by the time I got into my second and third trimester, I would maybe throw up once or twice a day, so it wasn’t as bad.” Not as bad as what? Chemotherapy?

Sally and I have been friends since college. We both live in the San Francisco
Bay area, and we get together every now and then to catch up. So when I learned an interesting fact about how taste preferences develop, I went to see her.

I started by asking Barrett, Sally’s precocious three-and-a-half-year-old, what her favorite food is.

“Pasta!” she shouted out without hesitation. “I like salt on my pasta! A lot.” Later Barrett said, “I also like chips and cheese.” At this point, her big sister Kathryn told me about Barrett’s diet, “Normally, all she has for lunch is chips and cheese.” Sally confirmed this. Sally said she would often make the girls sandwiches, which she’d serve with potato chips, string cheese, and fruit. Barrett would completely ignore the sandwich and fruit, eating only the salty chips and cheese.

“If I would let them, they both would load up the salt on their food. It’s to the point that it has to be supervised,” says Sally about her daughters’ intake of sodium.

Next I talked to Darren, who is Sally’s husband and Barrett and Kathryn’s dad. I asked him to describe the use of salt by the women in his family.

“It’s out of control,” he said promptly. “They put salt on everything. Barrett just asked for salt for her corn. She puts salt on her pasta,” he said, reconfirming what Barrett had told me earlier. “From very early on, Kathryn would always put salt on her food. ‘Pass the salt,’” Darren said, mimicking his daughters’ refrain at the dinner table.

Darren just assumed that his young daughters were mimicking their mother’s behavior; they salted their food because Sally salted her food, and this was now an ingrained behavior. I was fairly sure there was a different explanation.

Researchers in France have shown that maternal vomiting affected pregnant rats’ offspring. When I first read this, I imagined tiny radiantly pink rats, with swollen pregnant bellies, draped over teacup-size water bowls, waiting for their morning sickness to pass. But in fact the researchers had simulated the effects of vomiting by giving the rats polyethylene glycol, which made them dehydrated and, more important, made them crave salt. Sure enough, when the little pink baby rats were old enough to feed themselves, the ones from mothers who had craved salt during pregnancy were themselves saltaholics.

Researchers also tested four-month-old human babies for their preference for salty water. Sure enough, just like the rats, the babies whose mothers had suffered from vomiting when pregnant liked salt more than babies whose mothers didn’t get sick. If women are sick and dehydrated when pregnant (and ostensibly craving sodium, which they lose when they vomit), their fetuses experience
this craving, too, and the babies are then born with preprogrammed preferences for salt. This preference for salt continues well into adulthood. When researchers tested older children, their saltaholic tendencies had stuck around, well after they were weaned from their mothers and presumably fully hydrated.

Mothers don’t even have to consume a substance for it to influence their developing babies. The perfume that a woman wears can seep into the skin and make its way to a developing child. This is why I have an affinity for Chanel No. 5, the fragrance my mother wore when she was pregnant with me. When I exited the womb, supposedly innocent of everything, I already had a savvy ability to sniff out my mother. If the researchers had tested me at a young age, I would have had a measurable preference for the type of perfume my mother wore.

If the love for salt and perfume can develop in utero, what other food preferences are we born with, and which are learned?

Our likes and dislikes of the Basic Tastes are connected, beautifully, with our built-in will to survive. “Taste is hardwired because you don’t want the newborn to have to learn anything before it avoids certain problems that could kill it. Well, the first thing that’s going to happen to a newborn is that if it doesn’t eat, it’s going to die. So you hardwire sweet to be very good, and you make mother’s milk sweet,” says Linda Bartoshuk.

Human breast milk derives 40 percent of its calories from lactose, otherwise known as milk sugar. Put a bit of sugar on your finger
¹⁵
and put it in a newborn’s mouth and you’ll see that the baby will communicate to you nonverbally that
this is a good thing! Give me more!
Wiring kids with an innate love of sweet tastes helps ensure that they’ll be able to nourish themselves.

Humans also need salt to survive, but babies don’t have a preference for salt from day one, because they simply cannot taste it. Human salt receptors aren’t mature at birth, even for the offspring of mothers who had morning sickness. Their saltaholic cravings, like all human babies’, don’t kick in until a few months after birth. There’s a horrifying case of a hospital in suburban Sydney,
Australia, that proved this fact in the worst way. An employee in the children’s ward accidentally used salt instead of sugar to make the infant formula, which in the late 1960s required measuring and mixing. The newborn babies drank the formula without fuss, given their immature, nonfunctioning salt receptors. Soon they sickened, but by the time they were diagnosed with salt poisoning, the mix-up had caused the deaths of four newborns. Adult humans also can die from salt overdoses, so imagine how sensitive a baby’s system is to the effects of high levels of salt. Breast-feeding infants is safest for them, although most baby formulas these days already have the sugar included. If yours does not, move the salt container away from where you mix it up.

We know from research on salt preferences that infants develop a liking for salt at about four months of age. And then something interesting happens. Children under the age of three will drink salt water that a child over the age of three will reject. It seems that as the child’s salt receptors mature, she becomes more in tune with the context in which the saltiness occurs. After three years of age, kids will reject salty water yet accept salty soup broth at the same level of saltiness. Most adults reject salt water, which just doesn’t make culinary sense to us. Salty soup broth makes sense. Three years of age seems to be when food form and context become important in making decisions about what to eat. It’s when we begin to make sense of our food world.

Babies universally reject bitter foods. There’s a good evolutionary reason for this, too. Human babies are completely helpless when they’re born and rely almost entirely on adults for their survival. If a baby were left on his own, how would he know what to eat? Most babies will put anything into their mouth, and most babies take immediately to sucking on a nipple, no instruction required. They have the instinct to get things into their mouth. But if babies—and children—would universally swallow anything, they’d be at great risk because they have undeveloped immune and digestive systems. An instinctive rejection of bitter foods is thus protective of human babies’ lives. This explains why kids don’t (usually) drink coffee, tea, or enjoy Brussels sprouts or broccoli. It’s the remnants of their protective wiring hanging on. I asked Gary Beauchamp, director of Monell, if he had any advice for mothers who want their kids to eat more vegetables. His response was not to force children to eat anything. “Kids are smart not to like vegetables. They’re onto something. You’re fighting some real biology there,” he said.