NehaPathak, MD, FACP, DipABLM: Welcome to the WebMD Health Discovered podcast. I'm Dr Neha Pathak, WebMD's chief physician editor for health and lifestyle medicine. 

Today, we begin part one of our two-part series on ultra-processed food. What is ultra-processed food, and how does it impact our health, direct our purchasing choices, and change our perception of food prep and satisfaction while we're eating? What's the science behind the sensory experience of food and our cravings? What about that food chatter or food noise some of us experience? Join me as we take a step-by-step approach to the impact of ultra-processed food on the American diet.  

Joining me for our discussion today is Dr Barry Smith. Dr Smith is the director of the Institute of Philosophy at the University of London School of Advanced Study. 

He's a professor of philosophy and sensory expert. He's the founding director of the Center for the Study of the Senses, where he works with psychologists and neuroscientists to understand how taste, smell, and touch combine with other senses to create our experiences of flavor.  He's consulted with the food and drinks industry and worked with chefs, chocolatiers, winemakers, and whiskey blenders to enhance our experiences of food and drink and to explore the science of multi-sensory flavor perception. He's written theoretical and experimental papers for nature, food quality and preference, flavor, and chemical senses, as well as writing regularly for the world of fine wine.  

Welcome to the WebMD Health Discovered podcast, Dr Smith.   

Barry C. Smith, PhD, MA: Thank you. It's lovely to be here.  

Pathak: I am really excited to dig into our conversation, but before we do, I'd love to ask about your own health discovery, your aha moment around ultra-processed foods, and how that has changed the way that you eat. 

Smith: Sure. So, I was consulting for the food and drinks industry. It was, at first, a very welcome invitation because companies approached me and said, "We'd like to have you help us think of ways to reduce the salt, fat, and sugar in foods." I think that's good. I'm very happy to help with that. 

Their worry was that if they're taking some of those ingredients out or reducing them, maybe the foods wouldn't be so desirable, so palatable. They wanted to know what I could do as a sensory scientist to concentrate on the texture, taste, smell, look, and feel of these products that would still make them desirable and attractive. 

I was working away on this. Then I started realizing that quite often, they were asking me not just, "Can we take 30 percent of the sugar out, and it still tastes the same?" To which I would say no. But they were starting to say, "How can we make these foods irresistible? How can we make them so desirable that you just want to keep eating them?" 

I began to think that's not a terrifically good thing to do. It was around this time that I was in conversation with Dr Chris Van Tulleken, who was starting to write his book, Ultra Processed People. He wanted to know what the food industry was doing as strategies to get us to consume their foods and like our foods. 

I started realizing that I might be part of the problem because in working with companies to make foods more desirable, to give an enhanced experience of eating and enjoying these foods, maybe I was making them more palatable and actually helping to drive the consumption of them. 

When Chris started telling me about his experience with ultra-processed food and an experiment he did, where he went on a very intensive diet of such foods, he said, "I found myself being very sleepy, not concentrating so well. I was always hungry. I wasn't enjoying life nearly as much." 

I thought, Oh, that sounds familiar. That feeling that after you've eaten, you might feel rather full, and then a little while later, you might feel starving again and hungry. I wondered if these foods are so much in my diet that they're making me behave that way. So I started cutting them out, consciously looking at the back of packets and seeing what was in there and deciding to avoid them. 

After a while of leaving aside things I was used to or that were familiar or that I liked, I didn't miss them. I started losing weight without trying to, and the thing I found was I had more energy, I wasn't as tired, and I was not feeling constantly hungry. I began to realize it was not something about me and a kind of weakness in my desire for sugary, fat things. It's not just that I can't resist the pleasure of them. It's that these foods were inducing a state in me that was really not agreeable and healthy and that a little bit of time resisting them made them seem much less attractive, and that was when things started to get a lot better. 

Pathak: It sounds like, for you, a lot of it was education and learning about the health risks of these ultra-processed foods or how they made you feel. Can we take a step back and define what is ultra-processed food? 

Smith: It's a hard category to get at, the notion of a natural processed food, because there's a long definition. It was created by Carlos Monteiro and colleagues in Brazil, who came up with the NOVA classification system: whole food foods that have then been processed a little to make natural products or extracts that we then flavor other foods with and then fairly well-processed foods. But ultra processing is when we see ingredients on the back of our food packets that have chemical compounds and names of things that we wouldn't find in the ordinary domestic kitchen. A lot of food companies got alert to the idea that people didn't want to see soy lecithin and maltodextrin and methylcellulose and all those things on the back of the packets. They might be suspicious. So they've started to have superordinate categories that seem friendlier, like natural flavorings or just emulsifiers, or they have things like preservatives. Now, the trouble is that those are quite often just overarching categories under which we'll find things that have been industrially formatted. 

If you think of why the food industry did this, there are a number of reasons. One reason is that foods perish quite quickly when they have natural ingredients. They're also expensive. Food scientists thought of themselves as doing good work. In the food lab, can we make substitutes for some of these ingredients, which will just be cheaper and also maybe more stable and last longer on the shelves? 

Take something like mayonnaise. Mayonnaise has an emulsifier. You've got to have eggs, and you've got to have maybe olive oil, and you put them together, and that's how the whole thing binds into a gloopy texture that we love. We can coat things with. But olive oil is expensive, and eggs perish. So, can we make some soy-based alternatives? Can we find emulsifiers? Some of which are even made from cotton extracts. They're not even from food. So, you can find modified starches from cotton or emulsifiers from soy proteins. You end up producing these things, which, to the palette, seem as creamy, smooth, and enjoyable as mayonnaise. Still, the color of the thing doesn't like a naturally made mayonnaise. It is odd that it's not in the fridge and that it is not in a freezer and it or a refrigerator, and it lasts forever when it's on the shelf of a supermarket. So that's a little bit of a warning.  

Sometimes when these stabilizers or preservatives are in there, they might have a nasty aftertaste but don't worry because the food chemists can think of another compound to put in there to mask that flavor and to get us over the hump. So, by the time you start with a chemistry set to produce things that mask or imitate or simulate real foods, you're producing something that may have deleterious health effects on us. 

There's a lot of evidence, but it's correlational, epidemiological, and population-size studies. So, if you look at countries like mine in the UK or yours in the US, on average, adults seem to be eating about 67% of their diet involving ultra-processed ingredients. We've also got high levels of cardiovascular disease. We've got increased rates of obesity. We've got type 2 diabetes at a very high level. If you compare that with a country like France, where the same proportion of ultra-processed food in the diet of the average adult is about 17.4% and not 67%, you see a similar reduction in diet-related diseases, same in Italy. 

And so you think, well, maybe we should look into that, and we should start to consider whether some of the causes of these diet-related diseases are the ingredients and the foods that we're creating. But I'm also interested not just in the ingredients that are in there. I'm interested in the processes that are used to put them in there. 

So, for example, we talked about natural flavorings. You think, well, that should be good. It's natural food. Yes, but you can take a natural food, and you can then extract some ingredients from it or several ingredients from it. You can throw the rest away. You can reformulate it. You can inject it back into food. And that's a process that will give it nutrients, maybe vitamins, and other things. But it won't have the same bioavailability. The body won't uptake and know how to deal with those foods because they're not coming in tomatoes, or they're not coming in beans, or they're not coming in the usual shape that, for years and years, our physiology and body have been used to digest. 

So sometimes, the processing is only the processing of natural ingredients, but in a very highly industrialized way. Think of fruit juices that have got apple concentrate, no added sugar because it's got fruit in there, but once you concentrate and you squeeze all the water out and you get an absolutely concentrated pack of fructose sugar, you can douse the juices with that. 

And now you're getting an awful lot of sugar, but you say there's nothing unnatural about it. This is where I begin to worry that we're doing something in the food system. That's not very good for us.  

Pathak:So you were working with these food companies, not necessarily in this role, in terms of trying to make these foods addictive but really trying to help with the sensory experience. What was it for you that helped you to try to set this aside and try to down-regulate some of this in your own life? 

Smith: I'm very interested in the whole experience of eating because I'm interested in how the sensory inputs from touch and taste and smell and even from vision and the sound of food, the crunch and the crispiness of it in our heads as we're eating, how that gives us experiences we recognize, like and enjoy or how can we enhance them? How can we give ourselves a better experience?  

For me, the sensory experience of eating food begins before we put it in our mouth. When we look at it, when we see the packet, when we imagine what it's like to taste it, when we've got the aroma of roasted chicken as we're in the supermarket, or we're passing the smell of freshly baked bread, which a lot of supermarkets create, even though the bread they're selling is not baked on the premises, but you've got the smell that tells you, ah, freshly baked. 

Whenever you walk into a supermarket, the first thing you see are the fresh vegetables, and they're usually sprayed to be glistening. They're telling you everything's fresh, fresh, fresh. All these cues are about the desire for what you want to eat. So, the experience starts a long time before you put things in your mouth, and it lasts a lot longer. 

I was very interested in that whole experience, but I also began to see from the manufacturing and the care that multinational food companies were taking to ramp up sensations that we were getting, so everything was tastier, saltier, more zingy, and more powerful. The aromas as you open the bag of potato chips should fill the air around you, the crisp and crunch of them, the sound of the bag that was making, the rustling noise, all of that, making you think fresh, fresh, fresh. 

And I realized they're trying to make every tasting experience a carnival, a riot of flavors and sensations as though there should be fireworks going off in your mouth every time you eat everything. Why? Sometimes eating is just about eating. Sometimes it's nice and enjoyable, and we're consuming food, and it shouldn't be the only thing you're thinking about in the day. 

You should be saying, okay, now it's time to eat. What do I want? And then, do I feel satisfied? Good. But it shouldn't be that you've got to give yourself such a huge, intense experience of sensations and flavor sensations that if something doesn't meet that threshold, you're not interested in it, or you won't even try it. 

And I noticed that they seemed overdone when I came away from eating more of those foods. They seemed almost caricature-like. They were grotesque. Why were things so flavorsome and so intense? Did they need to be? No, I could now settle back and enjoy something simpler, you know, a handful of nuts, or you could be having some fruit, or you could have fruit and yogurt and walnuts and some honey drizzled over it. You've got different textures and flavors and starting to find that much more satisfying. 

And there's a natural way in which when you've had enough of that, you stop. I think it's not so easy, and it's become unnaturally regular for people to go on eating more than they want and go on seeking out more of these intense experiences. I think what we want is the intensity of the experience of eating a meal with others, not the intensity of sensations.  

Pathak: What is happening in our physiology in our brain with our neurotransmitters that makes us want that experience? Even if it's something that we don't necessarily like?  

Smith: We should bring out the distinction here between wanting and liking. This is a wonderful distinction by the physiologist Kent Berridge. Kent's very good at drawing the distinction. People think wanting and liking, isn't that the same thing? Not quite. If everything's going well, you eat something, you like it, and then you want more of it because you like it. That's usually the way it goes. But here are just a couple of examples of where it goes the other way around. When we were younger, we didn't like the taste of coffee or the taste of alcohol the first time we tried it. So why did we go on having it? Well, the adults were having it. It looked cool. It's a thing to do, right? Eventually, your physiology, like the caffeine hit, the post-ingestive effect of caffeine, which gave you a little rush, or the relaxing warmth of the alcohol made you calm down and feel much more social. We start to want those effects. So we learn to like the things that will predict them. 

We start liking that bitter taste of coffee or the bitter taste of alcohol. We didn't like it to begin with, but we want the effect. So, we'll start liking the thing that predicts the effect. The wanting system is run by the dopamine system. A lot of people mistake this neurotransmitter, and they often say, oh, dopamine is the pleasure chemical. It's the thing that when we have a lovely experience or get high from tasting something sweet, we get lots of dopamine. No, dopamine spikes when it predicts getting something you want. So that's why when you see the wrapper of the potato chips or the candy bar, your brain is already anticipating what it's like to eat that, which is what you want. 

In fact, we know that, especially among individuals with obesity, their visual cortex actually processes the visual signal of energy-dense food quicker than other people. It's as though their attention system is on the lookout for things that will give them a reward thereafter. 

This seems to be a way in which the food environment we're in is shaping us instead of us choosing which things in the food environment we want. And I do think that's happening with the kind of foods that food companies are putting out there. You know, they say, well, we just make these foods available, and people choose them. 

Um, I think they're shaping our dietary habits and patterns and trends, and they're sculpting our desires and our internal reward system to go after these. Now, when you have the click and the tear of a fizzy soda, a lot of work goes into making that sound just right. I mean, it's engineering to have the right click, tear, because click, tear is usually followed by glug, glug, glug, ah, and that little chain of sequences is getting you towards the reward you want. So, all the steps leading up to it are about motivating you to go all the way.  

Wanting and liking is interesting because we think of it as coming unstuck. So, in addiction, take alcohol or class A drugs. Somebody takes them. They like the effect. So they take some more, and they get the reward, and they take some more, and then eventually the reward slips a little. It's not as high. So they take increased amounts, and the reward just keeps slipping, and they keep having more and more to the point they're not even enjoying it anymore, but they can't stop wanting it because they're chasing that reward or their physiology is chasing that reward. 

So, for the person who's struggling with alcoholism, it's not the sip of the alcohol that's most dangerous. The most dangerous thing is the sound of a cheery bar. Because that's where they got the signal that was going to be the reward they enjoyed, and that's the hardest thing to resist. So all the packaging, the sounds of opening, the ripping open, the feel of the packaging in our hands, the smell when we open the wrappers, or we tear something open, all of that is a driver and a motivation to go on eating. And it's targeting wanting rather than liking. 

Pathak: That's so important. It gets to something that I think as a clinician is newly entering my understanding too, which is the concept of food noise that a lot of people live with. I hadn't necessarily really thought of that in my counseling when I'm talking to patients.  

Smith: I think that's right. They're living in a very noisy food environment that's bombarding them and motivating them, grabbing their attention, insisting that it primes their reward system and drives them to consume. In a way, people need help to reset. It's not just willpower. Oh, if you just had a bit more willpower, you couldn't do it. No, the resetting is avoiding those triggers and cues to begin with or allowing people to experience a sort of slower release and pleasure and not expecting the quick hit and gratification. 

For example, commercial chocolate melts very fast. Of course, what we love about chocolate is it goes from the solid state of a bar that snaps to something that in our mouth goes molten and luxurious and gooey. We love that texture, and, oh, that's the pleasure of chocolate, right? We're all there. But commercial chocolate very often gets there very quickly because it's melting in your fingers, even before you put it in your mouth. It's often full of palm oil because palm oil is a cheaper replacement of cocoa butter. And cocoa butter is only released once we melt the chocolate completely, whereas this is going to just ooze out. 

It means that the sugars are going to come out quickly. We're going to absorb sugar quickly. We get a quick hit. If you have chocolate with a higher percentage of cocoa solid in it, you know, 50-60% at first, whether it's milk or dark. You put it in, and at first, it's like putting a piece of Lego in your mouth because you don't taste it yet until it melts. 

I want you to do this exercise. I want you to think, I'm going to eat this as slow, slowly as I've ever eaten anything. I'm going to put this piece in my mouth. I'm going to just move it around my mouth, not bite it. And then notice what happens. It starts to melt. Ooh, I'm now getting a bit of taste. I get a bit of sweetness or a bit of bitterness. Ooh, and as it melts more, I'm getting that chocolate-ness, and, eventually, I'm getting that coating of my mouth. And so now swallow. And then I'll say to people, now you have a second piece of that chocolate. And now it's a competition. I want you to eat it as fast as you've ever eaten it. 

And when you finish, put your hand up. What did you taste? Nothing. I don't know. A bit of sweetness. They realize that the flavor that's coming out is better and can be enjoyed more when they slow down, and they appreciate it. And then they're satisfied more because they're not sort of just always saying, give me another hit. 

It's like, Ooh, I took my time, and I got more out of that. I think the resetting matters. Avoiding that noisy food environment and also keeping away from those big, intense hits of flavor sensations that are always supposed to capture your attention. Take a step back and then notice what's going on. You kind of get satisfied sooner, I think, when you do that because you get more out of the eating experience rather than just the reward for the hit. 

Pathak: That really makes me think of the concept of mindful eating and just really being thoughtful about every bite that you're putting into your mouth. Thankful for, having gratitude for, and enjoying every bite. 

Smith: That's right. It happens even in preparing food. It's not just about what you can afford. People who are time-poor will often think I'm just going to get convenience food, and I'm going to buy something ready-made, or I'm going to get a delivery from the supermarket or from a takeaway. You don't really know how much you're consuming because you're saying, well, it's about the size of a meal, but quite often, some of those ready meals are so energy-dense. Some of them can contain 1800-2000 calories. I mean, that's a large part of your total volume of input in this single dish. Whereas if you were chopping and making and putting things together, you'd kind of know what went in there. Your brain would be anticipating what you're going to get out of it. You would be paying attention as you're eating it. We also know there's great research about if you're eating in front of the television; people eat more and eat more quickly because they're not looking at their food. Whereas the cue about what am I getting and what it tastes like is going to be a much stronger signal if you're looking at food and thinking about the food. So mindful eating is actually part of how we regulate our own intake because we don't judge if we're full and we've had enough in real time. Our physiology takes a long time to tell us when we've had the nutrients, the sugars, the fats, the carbohydrates that we were wanting to take in or needing to take in the body processes that quite slowly. 

So you could be eating and eating and eating. And then it's only a little bit later. You think, oh, I ate too much. I shouldn't have had all of that. Whereas, if you're looking at what you're eating and predicting what the effect is going to be on your body, both internally in how you're processing and digesting and visually how you're monitoring what's happening in real-time, you will go bring those two together, and then probably you won't overeat. 

Pathak: Thank you so much for being with us today. We've talked with Dr Barry Smith about the health impacts of ultra-processed foods and the food industry's goal to make foods irresistibly desirable, raising concerns about the link between these strategies and negative health outcomes or increased cravings and overeating. We discussed how ultra-processed foods are laden with ingredients and additives that our bodies struggle to digest, contributing to issues like obesity, cardiovascular disease, and type 2 diabetes. Dr Smith emphasized that food companies use sensory manipulation to make foods more appealing by intensifying taste, aroma, and texture, which drives overconsumption. He highlighted the distinction between wanting and liking. He noted how dopamine, the brain's reward chemical, fuels our desire for foods through sensory cues, even when the actual enjoyment is minimal. As we'll talk about more in part two, he advocates for mindful eating, encouraging us to slow down and savor each bite, and be conscious of what we're eating. By adopting this approach, we can develop a healthier relationship with food, focusing on satisfaction and balance instead of constantly chasing heightened sensory experiences. Please be sure to join us next week for part two, where we'll discuss more tips and strategies to hack back our brains and behaviors to shift toward healthier eating. To find out more information about Dr. Smith, visit our show notes. Thank you so much for listening. Please take a moment to follow, rate, and review this podcast on your favorite listening platform. If you'd like to send me an email about topics you are interested in or questions for future guests, please send me a note at webmdpodcastatwebmd.net. This is Dr Neha Pathak for the WebMD Health Discovered podcast.