Why Do We Like Food? The Science of Taste and Eating Thanksgiving Dinner Explained

When children are asked to eat something they don’t like at Thanksgiving dinners, grown-ups often tell them to hold their noses. “You won’t be able to taste it that way,” generations of parents have claimed. It doesn’t work that well, as anyone who has tried to choke down something distasteful can attest—but there may be a tiny bit of science to it after all. The scent of a Thanksgiving dinner, it turns out, is part of why an apple pie might be so alluring or green beans so repulsive, according to an expert in the neuroscience of taste.

Charles Zuker, a neuroscientist at Columbia University’s Zuckerman Institute has published several papers on exactly how brains process taste, mostly based on experiments done in mice brains. “One of the most important discoveries that has emerged from the science of taste in the past 50 years or so is the discovery that each taste is mediated by its own class of taste receptor cells in the tongue,” Zuker told Newsweek.

There are five general classes of taste receptors: sweet, bitter, sour, salty, and a taste called umami, a savory, meaty kind of taste. These five distinct tastes each contribute in different ways to our daily survival (in the video accompanying this story, Zuker explains how).  Each of our approximately 10,000 taste buds contains taste receptors of all five classes. These taste receptors—proteins that specifically match up to the different molecules that carry each type of taste—have very high turnover rates; receptors you have at Thanksgiving won’t make it to Christmas. This may be because your body needs fresh reinforcements regularly to make sure everything works as well as it can—especially if you consider the hot, cold and spicy foods that taste receptors are subjected to every day.

GettyImages-625708994 (1) A Guatemalan immigrant carves the Thanksgiving turkey on November 24, 2016 in Stamford, Connecticut. John Moore/Getty Images

Experiments in mice have shown that activating certain receptors will result in very predictable actions. Bitter food can trigger gagging reflexes, for example. But this behavior isn’t something people learn, Zuker found. It’s hard-wired into your brain. Each taste receptor connects to distinct brain regions associated with each of the five tastes. So when Zuker and his team stimulated the brain region associated with bitter taste, even mice that were genetically modified to not have bitter taste receptors still acted as though they had tasted something bitter.

Of course, humans are not mice; sometimes, we are far sillier creatures. “What other animal is drinking coffee out there or tonic water?” Zuker noted. And taste is more than just a bunch of neurons firing. “It is quite likely that all of the things that we define as flavor are the result of a combination of all of these five taste qualities plus the activation of all of these other senses,” Zuker said—like smell.

Even if we are able to stomach some bitter pills or potables, there comes a limit. So, returning to that nose-plugging trick—at its root, people who use it are trying to make their brains believe those dreaded green beans aren’t green beans but something different instead. It doesn’t really stop us from tasting flavors, Zuker said. “What you may argue, though, is that things may taste a lot blunter. I can plug my nose and still tell you that sweet is sweet,” Zuker said. “It’s just that when you taste something familiar, it’s no longer familiar.”

Good enough for green beans.