Sense of Smell & How it Creates Flavor
The sense of smell plays a huge role in what we choose to eat. We’re not mindful of the patterns the brain conceptualizes when it comes to our perception of flavor. Gordon Shepherd, professor of neurobiology at Yale University and writer of Neurogastronomy: How the Brain Creates Flavor & Why it Matters explains the mechanics of smell and why we crave the foods we eat and how the food industry has largely influenced our preference in flavor. What we eat is not just taste, but flavor due to smell and the retronasal effects.
What is Neurogastronomy?
Gastronomy is a pleasure we get from the food that we eat, then Neurogastronomy is how the brain actually creates those flavors. It’s the key to understanding why we eat what we do because how the brain makes the flavors and determines what we like. Why that matters is because food companies all know this. Food companies have their own scientist working away around the clock to understand as much as they can about why we like what we do. That leads them to analyzing how the brain creates the different flavors and how the brain creates our craving for those flavors.
The idea behind Neurogastronomy is that we, the public, should understand as much as the companies do about why we like the foods that they make for us, so we can better understand how to make better choices, healthier choices of the foods that are going to good for us and avoid the ones that are bad.
Why does the sense of smell matter so much in flavor? Can you explain this process?
Let’s compare first to taste, so you know there are five tastes; sweet, salt, sour, bitter, and umami, which is a kind of meat, savory taste. And that’s pretty much the same in the world around. Salt is salt, sweet is sweet but smells are quite different. Smells are something that we have hundreds of receptors for and each person has a different combination. Many of them are the same but a number of them are different, simply through genetic inheritance. The other thing is that smell is very open to learning, so whereas we don’t learn to like salt because we have to have salt for our health and we don’t learn to eat sweet. Humans through evolution have always looked for sweet fruit and vegetables because sweet and sugar carries energy. The sense of smell doesn’t have those kinds of inborn smell needs, so that means that they are very adaptable to different cultures and different families and different individuals. So we all grow up with our own world of the country we’re in, the family we’re in, the community we’re in, and our own individual flavors. Almost nobody has the same preference for flavors as anyone else and that’s mostly because of smells and the hundreds of receptors and because of the very complex patterns that they stimulate in the brain so that each of us have a pattern in our brains when we eat, even when we eat the same thing and that determines if we like it.
Smell is not the smell that we’re conscious of when we’re sniffing in, the smell is the smell when we’re breathing out—we call that retronasal smell, going backwards. When you sit down for dinner tonight you’ll be totally unconscious of it. You’ll think it’s all coming from our mouth and all taste but in fact, much of the flavor is due to smell and when you’re breathing out, when you’re not conscious of it. Food producers are actually creating an illusion that they manipulate so they can hook you on their food.
The brain creates cravings as well. Using brain imaging, it’s been able to show parts of the brain that are activated when people are craving their favorite food. It’s the brain that creates, not only the sense, but also emotions. [Cravings] start before birth, what the mother eats is an immediate influence on what the infant is going to prefer in their first months of life and even longer. These effects start early and that to a large extent to the contribution of the sense of smell.
Even if we all have unique receptors in our noses, is there still a common pattern in what we’re attracted to?
That’s a very good point and that’s what I was indicating, is that many of the patterns from the different smells will be very similar. So most humans like the smell of frying meat, for example, and this is where human evolution comes in. That reflects the fact that humans have been preferring meat as much as a million years in evolution. This then gets genetically built into us as well as culturally built into us. Different kinds of meat are attracted just as there are different kinds of sweet fruits that are usually attracted, so the patterns can overlap just as faces. Each of us can look at a face and if it’s a face making a fierce face at us, almost everyone would reject it. If it’s a smiling, beautiful face, then most of us would be attracted to it. I think it’s something similar with the patterns that are created in our brain by smells as well as taste.
Can you explain your book, Neurogastronomy: How the Brain Creates Flavor & Why it Matters?
The brain creates flavor through the different senses that are activated that create what’s called, a multi-sensory image within our brains. This starts out reflecting the different senses that are activated but as the sensory information gets processed, it gets converted into something internal within the brain itself and it becomes a representation of what we call flavor which is a representation within the brain of the molecules in the forms it stimulates. Again, it’s like seeing different faces. It’s difficult to describe in words a face but we’re all good at identifying a face, someone we know or someone in our family. The reason it matters is because of what I indicated, food producers are constantly trying to persuade us the patterns and activities in our brains activated by lots of salt and lots of sugar, and something that we should eat more and more of. [For example,] in a can of Coca-Cola, it’s the sweet taste and the special flavor that coke puts in there that makes its very impossible to resist.
Do you believe our flavor palate is not mature?
It’s food producers that are producing food that over stimulate us. Most traditional cooking involves a variety of things, some meat, some fish, some carbs, and vegetables. It’s a mix of things that has a combination of different flavors and different amounts of foods that fill us up. Usually, a traditional meal has a modest amount of calories in it and a modest amount of any particular thing like salt or sugar, but things that food producers and fast-food restaurants want us to eat have flavors much more intense and much more compressed into the food that they offer, like a Big Mac. Where then one serving of a Big Mac along with the soda and fries that go with it, you get an entire day’s vision of calories just from that one meal. This is why it matters to understand what the food producers and restaurants are trying to get us to eat and to be much more informed about it.