Kids who hate stinky cheese and greens often grow into adults who can't get enough of them. Why do our tastes seem to transform in our teens? And can we change our tastes deliberately as adults? Here's what scientists know so far.
Let me start by saying that I love food. I know, countless other people have said the same thing, but go with me on this. I cook a dinner for two almost every night, and at least once a week I like to try something new. Sometimes my experiments are small — I may add a new ingredient to an established recipe. Other times I'll go crazy and just throw a bunch of stuff into a slow cooker to see what happens.
But I wasn't always so adventurous with food. As a kid, I hated vegetables, including tomatoes, onions and peppers, along with many other things (spicy food? No thanks.). That changed in my teens, seemingly overnight. I never understood why my preferences flipped; I just thought it was all part of "growing up."
Now, years later, I figured science must have more to say on this issue than that. So I spoke with psychologist Elizabeth Phillips to find out just how our food preferences come about. Phillips, whose research focuses on the psychology of tastes and eating, is the executive vice president and provost of the Arizona State University.
There are several factors that help define our food preferences, Phillips said, adding that we can change the foods we enjoy if we so choose. It just takes a bit of time and effort.
The first thing to know about our food preferences is that genetic influences play a surprisingly small role in the matter. We are born with an innate like of sweetness and a dislike of anything sour or bitter.
These taste partialities have evolutionary roots. Sweet foods, such as fruits, are good sources of nutrients and energy, so we are predisposed to like them. "Ripe fruits are generally safe to eat and have a lot of vitamins," Phillips says. "And ripe fruits are naturally sweet." Bitter tastes, on the other hand, are common in plant toxins, so we are hardwired to detect and dislike them. This aversion to bitterness partially explains why I — along with most other people — once hated certain vegetables.
Newborns have immediate reactions to sweet and bitter tastes, while salt preferences develop shortly after. Our love of salt may be an adaptive trait, too. "Salt lakes often have all the other minerals you need to have to survive," Phillips says.
We are also built to favor fatty food for their high calorie count, which provides us with necessary energy. So you're particularly bound to savor anything that hits you with a fat-sweet or fat-salt combo (ice cream and French fries, anyone?).
Some research has shown that there are gender differences in what foods we like to eat, Phillips notes. Men apparently like meat, while women like sweets. Though this difference may have a historical basis (before agriculture, men hunted while women picked fruits), it probably also has a lot to do with how we view different types of food (meat is supposedly manly, for example). "As they say, 'you are what you eat,'" she says.
While these innate factors do influence our food choices, the preferences we develop in our lives are mostly learned, Phillips says. And they can begin before we are even born.
Inside of the womb, the fetus inhales and exhales amniotic fluid, which is flavored by the mother's dietary habits. Scientists have shown that newborns who were prenatally exposed to garlic or anise in amniotic fluid had a less negative reaction to the odors a few days after birth, compared with babies who had no previous experience with the spices.
In another study, infants appeared to enjoy carrot-flavored cereal if their mothers regularly drank carrot juice late in their pregnancies, or for a couple months after giving birth (in which case the babies were exposed to the carrot flavor through breast milk).
After birth, your preferences continue shaping for the next two years. "Up until the age of 2 you will eat anything," Phillips says. But then you become neophobic — that is, you don't like new food. So if you hadn't already been exposed to a certain flavor by the time you hit your terrible twos — whether through amniotic fluid, breast milk or solid food — chances are you won't like it.
At this point, most parents make a big mistake. "They think, 'Oh my child doesn't like this,' but it's actually anything new that they don't like," Phillips says. So parents typically stop trying to feed their child that food and the kid ends up apparently hating it for years to come. "They don't know that if they just keep giving it to their child, they'll eventually like it."
The key, then, is to make the food not new. Basically, you'll like a new or previously hated flavor if you're repeatedly exposed to it — studies suggest that it takes 10 to 15 exposures. "So if there's something you don't like, just eat it over and over and over again," Phillips says.
I can certainly attest this idea. Up until middle school I didn't like mashed potatoes. I ended up loving the mushy stuff only because I forced myself to eat it during school, just so that my friend — who wouldn't give me his delicious bread rolls — couldn't have it (yes, I know, it was kind of a dick move).
The point is: We don't just eat foods because we like them, we like them because we eat them.
But what if you really can't stand something and the thought of eating it 10 times is enough to make your hurl? In this case, you can try to build a preference for it through association. Five years ago, Phillips found that she could get kids to eat broccoli by adding a dash of sugar to it. After doing this about six times, the kids actually enjoyed eating the broccoli by itself.
Looking back, I think I learned to like a lot of vegetables in this manner. For example, I now eat tomatoes, which I once hated, probably because I had a big appetite for Mexican pizzas in my teens.
Today, however, I'm still not a big fan of green beans. Phillips's advice? Mix it with mashed potatoes. "You can really mix it with anything you already like, but you have to still be able to taste the thing you are trying to condition for," she says, meaning that I must be able to still taste the green beans if I want to eventually like its flavor.
Learning to like a new flavor is relatively easy, but switching to a whole new diet takes time, Philips says. If you try to go from drinking whole milk to skim milk, a dozen glasses probably won't cut it — you'll likely still think the skim milk tastes watery. Such a change will instead take 2 to 4 months, she says, and then you'll find that whole milk is too creamy or even greasy. Trying to switch to a low-salt diet also requires diligence. In these cases, your body is already very used to certain things, so it's more than just making a psychological adjustment, as it is with learning to like new flavors — you're taste buds need to adjust, too.
Lessons from taste psychology
For the most part, our food preferences are learned, though we have a predisposition to like certain tastes. It all seems simple enough, but there's a lot more the psychology of taste can teach us about what we like to eat.
For example, some people are considered "supertasters." These individuals, in general, taste bitterness more intensely, so they are more likely to avoid green vegetables, Phillips says. "I believe there's actually sweet supertasters and sour supertasters, too" she adds. "This is an area of active research."
Another thing to consider is the role that our other senses play in our food preferences. We all know that the smell of food affects how it tastes, but visual cues also matter. If you change the color of a common food or drink, such as making grape juice green, people will perceive the flavor as being different. Some of us also have biases against certain textures, Phillips says, though we can learn to get over those feelings.
Now, we've discussed how we learn to like new food, but what does it take for us to newly dislike something? It's simple, actually. "The food just has to make you sick," Phillips says. If something makes you sick, you develop a natural aversion to it — the taste and even smell of the stuff will no longer sit well with you. This taste aversion is a survival mechanism, where your body is essentially trying to avoid a potentially poisonous substance.
Taste psychology is an active field right now, with potentially important consequences for what and how we eat. It will be interesting to see what future experiments further tell us about our food preferences. Now, it's time to conduct my own experiment: Mixing green beans with mashed potatoes.
Correction: The article previously stated that Phillips is associated with the University of Arizona. She is actually affiliated with Arizona State University.