We Asked a Taste Expert Why Some Foods Make People Gag

What’s the deal with taste? Why am I happy to eat mustard on crackers but others will gag at anything but free-range organic orange pulp?

Dr. John Prescott, a specialist in the human perception of taste and smell, dedicated his life to solving that very question. In his recent book Taste Matters, Dr. Prescott delves into the origins of our food preferences—whether they’re genetic, cultural, or learned.

We called up Dr. Prescott to ask why some people think some things are more delicious than others, and whether babies are born loving chilies.

MUNCHIES: Hi, Dr. Prescott. First thing: If I eat a piece of chocolate and you eat a piece of chocolate, are we tasting the same thing? Dr. John Prescott: Very good question. It’s more philosophical than anything else. It’s like saying, “Is the red that I see the same as the red as you see?” Of course, there’s no real way of answering.

The answer is: probably—with relatively minor differences. You might be more sensitive to dark chocolate or the bitterness than I am. You may regard it as very sweet if you don’t eat chocolate very often. That’s an issue with the way our brain compares experiences.

If I hate something you like, is it our brains or mouths that are different? Everything is in the brain. When we talk about likes and dislikes, it’s pretty much always about exposure. My wife, for example, doesn’t like lamb because of that lamby smell. She wasn’t brought up eating lamb. I was, so I quite like that flavour.

That sort of different exposure to things accounts for most differences in taste preferences. There are some relatively minor differences—again in sensitivity to bitterness—but those things don’t count for an awful lot.

So, if it’s mental, you can teach yourself to like and hate things? Most people have had the experience of starting off hating something, but eating it because their friends eat it, and they actually end up liking it. And that’s not so uncommon. So that’s primarily what’s producing the change, just the exposure.

What about people who taste coriander as soapy dishwater? What’s that? That’s one of those minor differences between people. They have a genetic variation that simply means that coriander tastes different to them. That’s quite a common one; a good percentage of people find coriander quite objectionable.

Are there other foods like that? Some people don’t like pork because it tastes very barnyard-y to them. That’s another genetically determined variation where some people are very sensitive to a compound called androstenone,a pig pheromone.

If it’s genetic, can you inherit preferences from your parents? Yes, you can, actually. Something like 50 percent of food preferences are inheritable.You get preferences from your mother’s diet when you’re in utero through flavours you’re exposed to in the amniotic fluid. You can demonstrate, even a couple of years after weaning, that they have a preference for those flavours.

So, if I don’t want a fussy child, I just need to eat everything when I’m pregnant? That’s exactly right. In fact, you could give the child specific preferences. If you wanted your kid to love carrots, you could eat lots of carrots. If you ate a lot of variety, your kid could end up liking variety for its own sake. That’s probably the biggest influence you could make.

A lot of people tend to grow out of their sweet tooth. Why is that? We’re not entirely sure. I think we’re born pretty much the same, liking sweet things. But we start to experience sweetness in particular contexts and not in others, and we get to like foods without sweetness in them.

Are Thai babies born with more of an affinity to chili and fish flavours than babies born in Ethiopia? Probably not chili, but fish type flavours, yeah. If the mother’s diet was likely to have that while the child was in utero, the child will be born familiar with fish flavours.

But chili is different? Yeah, chili is basically capsicum with heat. The capsicum flavour is exactly like any other flavour. The actual heat isn’t a taste, it’s a compound called capsaicin—a chemical irritant. The heat from chili is just pain nerves being activated, but of course you can learn to love that.

So, people aren’t born with an affinity for chili—they have to build it up. I think that’s true. We don’t know much about whether chili flavours or heat are present in the bloodstream or mother’s amniotic fluid. But I think it’s not.

Let’s say we lived in the future and I got a tongue transplant. Would I inherit the tongue donor’s favourite food? No. It’s like saying if you had an eye transplant, would you have memories of everything they’ve ever seen? Taste doesn’t happen in the tongue—it all happens in the brain. Our tongue is merely a device that converts chemicals into electrical signals, and that’s all it does.

Yeah, I didn’t think it would. What’s the most hated flavour in the world? That’s a tough one. Anything that’s rotten—vegetables and meat develop particularly flavours when they rot, due to enzymes that break down tissue. But of course there are wonderful examples of where people deliberately make food rotten and then eat it. I open my book with an example of rotten shark meat that people in Iceland eat and love. To me, that’s the worst thing I can imagine. But you could imagine almost anything and you’ll find somebody somewhere who thinks it’s delicious.