It turns out our taste preferences are set before we're even born
On average, Americans spend at least 67 minutes out of every day eating, and we try to make sure we spend that time eating things we enjoy. Most of us would agree that macaroni and cheese, bacon, pizza, and chocolate are magically delicious, but what about liver and onions or chitlins? How about a nice steaming bowl of fish head soup or calf’s brains in black butter?
Somewhere in the world (probably France), calf’s brains in black butter is someone’s favorite food. Fermented shrimp paste is a much-loved ingredient in the cuisine of about one-third of the world’s population, but most Westerners would shudder at even the thought of eating this strong smelling, fermented condiment.
So where do our food preferences come from? Does it simply boil down to what we are brought up to eat or is there something more to why we choose one food over another?
Toss out the tongue map
At the beginning of the 20th century, a German scientist found that some parts of the tongue seem to register specific flavors more intensely than others. Like a good scientist he made a graph, published his findings and faded into history. Then in the 1940’s a Harvard scientist discovered and promptly misinterpreted that graph, creating a map of the tongue’s surface where each taste has its own little fiefdom of flavor—bitter in the back, sour & salty on the sides, and sweet on the tip.
A poster of this “tongue map” hung in grade-school science classrooms for decades, confusing multitudes of students who dabbed swabs of lemon juice all around their tongue, only to find that they could detect sour flavor all over their tongue. Am I saying your sixth-grade science teacher was wrong? Yes—and my sincerest apologies to Mrs. Anderson.
Since the late seventies, we’ve known that while receptors for some tastes are more concentrated in certain parts of the tongue; all parts of the tongue, including the throat and soft palate (on the roof of your mouth) are sensitive to some degree to all five tastes.
But wait, we were taught that there are four tastes—salty, sweet, sour, and bitter. What’s this business about five tastes?
In reality, there are at least five tastes: sweet, salty, sour, bitter and the newest addition to the pantheon of piquancy, umami. This is the savory, mouth-watering taste you experience with foods such as seared beef, mushrooms, ripe tomatoes, and MSG. Umami was first identified by a Japanese chemist in 1908, but took almost a century to gain attention in the West, even longer to creep into Mrs. Anderson’s science class.
So how do we taste?
How the flavor of a strawberry, steak, or any other food makes its way to the brain and registers that soul hugging feeling of deliciousness involves the tongue, the nose, the brain, and a lot of geeky science stuff, so hang on to your beanies.
Technically speaking, taste doesn’t happen with just the tongue. The tongue is merely a translator, converting the chemicals in your food’s flavor molecules into signals for your brain to interpret. The tongue’s taste receptors don’t produce tastes on their own; they have to communicate with taste centers in the brain.
When you take a bite of a strawberry, for example, the fruit’s flavor molecules wash over your tongue and attach themselves to a taste receptor located on the tip of each taste bud. These bulb-shaped buds each have between 50 and 100 cells that correspond to all five flavors.
The strawberry flavor molecules’ specific size and shape match up to the sweet and sour taste receptors in the taste bud to initiate what Monell Chemical Senses Center Director, Robert Margolskee, calls a “Rube-Goldberg-like reaction” of signals. These signals alert the brain that the flavor you’re experiencing is the sweet, pleasantly sour taste of a beautifully ripe strawberry.
But the tongue is not the only player in the taste game. As we chew and swallow, airborne food molecules are drawn into our nasal cavity from the back where they bind with hundreds of odor receptors. While the tongue detects the five broad categories of tastes, the nose recruits hundreds of its own receptors to pick up on the varieties of chemicals that rise from our food as we eat to create a more complex snapshot of flavor.
This combined effort creates a powerful association between the flavor of a given food and our desire to eat it again. But there are other factors that come into play long before we even take our first bite.
Why we like what we like
Of all the factors that impact our food preferences, familiarity is the biggest reason we like most of the foods we like and reject the ones we don’t. Before we were even born, we were exposed to a full menu of flavors through our mother, and the flavors of the food she ate affects the way we respond to those same flavors after we’re born, especially if we were breast fed.
It’s estimated that 50 percent of our food preferences are a result of what flavors we were exposed to through inhaling and exhaling amniotic fluid in utero and through breast milk, both of which are flavored by the mother’s dietary habits.
In 2001, Monell researchers found that infants whose mothers ate a lot of a particular food—such as carrots—were more likely to enjoy carrots after weaning. Other research found that babies whose mothers ate a lot of garlic or anise-flavored foods while pregnant were more accepting of those flavors and smells after birth compared to babies that were not exposed to those flavors.
This provides a strong case for how preferences in regional cuisines around the world develop and are passed from one generation to the next such as a preference for fishy flavors from birth in babies from Vietnam and Thailand or my insatiable cravings for sweet tea and chicken livers.
This doesn’t mean that a baby who was weaned on formula or whose mothers survived on a diet of chicken nuggets and pizza is doomed to become that weird kid who never eats vegetables. Babies who are repeatedly exposed to a particular food eventually come to like it (barring genetic factors). So if your baby spits out his Brussels sprouts the first few times he tries them, just keep trying.
We are all born with a genetic disposition to reject bitter foods, so if you want your child to grow up to eat all their veggies, you have to provide them with repeated opportunities to eat them.
If you want your child to enjoy a wide variety of foods, make sure the mother eats a varied diet while pregnant and provide a wide range of foods to the baby while it’s an infant. Babies are surprisingly open to new flavors between four and seven months old. But if your child is already long past that window of opportunity, don’t worry. Even as adults our preferences can and do change if given the opportunity. While living in Thailand, I developed a preference for prik nam pla—a mixture of fish sauce and chilies that I would have never touched ten years ago.
Genetics can also play a role in some food preferences. About ten percent of the population is born with a group of genes that allows them to detect the smell of a chemical in cilantro that makes it taste soapy. Some people don’t like pork because they are unusually sensitive to a pig pheromone called androstenone.
Around 30 percent of the population is born without the ability to taste certain bitter flavors, while the presence of different receptor in other folks makes them more sensitive to bitter foods such as broccoli and leafy greens.
Of course, evolution has a part in food preferences as well. We like foods that are high in nutrients and calories because they help produce energy, but they may also contain things that are harmful, such as parasites or bacteria. Our senses of taste and smell evolved to serve as a warning system to our brains that bitter things may be poisonous and putrid things might be spoiled.
For millennia, if you didn’t breast feed your baby it was unlikely that it would survive, so it was in the interest of the species for us to develop a preference for sweet, just as it was important to develop an aversion to bitter. Sweet foods such as ripe fruits, are good sources of nutrients and energy and human breast milk is chock full of lactose, a sugar that babies are born with a preference for.
The tl;dr version: it’s complicated
So why do we like some foods and not others? It could be genetics; it could be evolution; it could be something physiological. But most likely, it’s because we were repeatedly exposed to those foods over time while in utero, breast feeding, as an infant, or even while eating with family and friends. So the next time you’re chowing down on a plate of fried pickles wondering how anyone could eat fermented fish parts, goat kidneys or Easy Cheese, just remember it all started before we were even born.