Ultra-Processed Foods with Alex DiFeliceantonio

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Travis

What do know about ultra-processed foods? If you're familiar with the term, it's very likely that it comes with at least a little bit of a negative connotation. It is very likely that you have seen or heard the messaging that these foods are dangerous to our health. But what exactly do they do to our health? What makes them so dangerous? And by the way, what exactly qualifies as an ultra-processed food anyway?

Well thankfully Virginia Tech's Alex DiFeliceantonio is an expert in this very subject and was kind enough to answer all these questions and more. Alex is an assistant professor with the Freeland Biomedical Research Institute at Virginia Tech Carilion and interim co-director of its Center for Health Behaviors research. She's a neuroscientist who studies how the brain integrates peripheral signals to guide food selection and eating behaviors and using multimodal brain imaging and metabolic measures lab in Roanoke studies food motivation to ask new questions about diet, food choice, and addiction. So Alex helped me understand where this term ultra-processed actually comes from and what qualifies as ultra-processed, as well as where dinosaur-shaped chicken nuggets fall on that spectrum. She also shared with me the impact these foods have on both our bodies and our brains when we eat them, and how both of those, as well as our society in general and the food options that we have, play significant roles in the dominance of these foods in our culture. and she makes at least one reference to Beetlejuice. So stick around and see if you can catch it. Be sure to follow, rate, and or subscribe to the podcast. I'm Travis Williams, and this is Virginia Tech's Curious Conversations.

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Travis

Maybe a good place to start is simply, are ultra-processed foods? What are we talking about when we talk about those?

Alex

Yeah, so generally when we're saying ultra-processed in a scientific context, and then also in a lot of the things that you see in the media, they are referring to a particular scale. So a particular set of definitions to say, okay, what foods are minimally processed, what foods are ultra-processed. And what that scale is the kind of most popular one, there are a couple out there, but the one that's got like the most research and we kind of have the most evidence and support for is what's known as the NOVA Scaled, N-O-V-A, all caps, but oddly enough, not an acronym, just to make it very confusing. But it's called NOVA because it was developed by a man named Carlos Montero in Brazil. He's a researcher there. And NOVA means new in Portuguese. And so the reason that it's a NOVA scale and why it's new is because he was noticing that There were a lot of kind of multinational food corporations, a lot of big grocery trades, a lot of processed and ultra-processed foods entering the Brazilian market and replacing a lot of traditional Brazilian food ways. And because he was a researcher, he's a scientist, he wanted a way to understand what was happening and to document what was happening. And so, he created the Nova Scale as a way to categorize the foods so that he could then understand, what is actually currently in the Brazilian food supply? What are people eating and how is it changing? So that's really where it comes from. And I think that's important context because the Nova Scale makes some definitions that really only make sense kind of in that context. So it's got four categories. We can start with ultra-processed if you want, which is Nova 4, that's the top category. And all the Nova 4 foods are foods that essentially you cannot produce them in your home kitchen. So they are foods that are produced either by industrial processes that are not available to the home cook. You can think of things like really high heat or extrusion or pressure or they can contain ingredients that are not available to the home cook. And so you can think about that when you turn the package over and you're like, I don't know what that says. I've never seen that in my life that is gonna help you identify what is a nova 4. Or if it's in like a shape, you can think of like, so I think that's the thing that sometimes confuses people is it's not just ingredients, it's also the methods by which the thing is produced. So if it's like, if it's a product in like a shape that you're like, man, I have no idea how they made this, it was probably through an industrial process that would qualify it.

Travis

So like a dinosaur shaped chicken nugget.

Alex

Yeah, exactly. Like if you're like, how do they make chicken in a dinosaur shape? You probably are looking at at a Nova 4 food. And then I think the other thing that people get confused about with the Nova scale is because it is one, two, three, four, they think, okay, one, two, three, four, we're kind of increasing risk or increasing level of processing across those across the numbers. And that's not quite right. So Nova ones are minimally processed foods. And so those are things like raw ingredients. Think about the produce department, like meats in the butcher department. Most people don't eat a really heavily like NOVA 1 diet. If you ate a salad with no dressing, that whole meal would be a NOVA 1. NOVA 2s are processed culinary ingredients. These are things like flour, butter, oil, salt, things that have undergone probably substantial processing. But again, it's important to remember the context in which Nova was created. These are things that are available in your home kitchen. These are things you can cook with that you can make yourself, right? Like oil has undergone a fair amount of processing, but you can go buy it at the store and you can use it in your own foods. And then Nova 3s are probably like the, are things that we would think of a lot of foods that we eat, right? So these are processed foods, but not ultra processed. Nova 3s are things like canned vegetables, frozen fruits. And essentially, like anything that you would make in your home kitchen out of Nova ones and twos would be a Nova three. And so that's the categorization system that we're using when we're talking about ultra processed foods. When we're talking about the health effects of these foods, the most research has gone into kind of understanding these foods as classified by the Nova system. Way longer answer than you wanted.

Travis

No, that's really fascinating. Do you know, when did that scale come about? When did he create that scale?

Alex

That's a great question. So it was about, I think the first paper was in like 2009, but it started gaining a lot more popularity later on. I can look up the exact when it was the exact first paper.

Travis

So relatively new then, these words.

Alex

Yes, exactly. So this idea of ultra-processing is relatively new and it's surprisingly new given when these foods entered the food supply in the United States. So there is, if you kind of look and take this definition and kind of go backwards in time and say when was this big surge in ultra-processed foods in the United States, that actually happened in the late 80s in the United States. That's when we see this kind of big increase in ultra-processed foods. Now what we're dealing with is, if you look at calories consumed, so the average person and you kind of figure out how many, what are they eating? About, sorry, 58 for just your average adult, 58 % of calories consumed in the US come from ultra-processed foods. If you look at our food supply, go to the grocery store and like categories everything. That number is more in the low 70s. I think it's somewhere around 73% foods that are on offer to you. So the share of the market and the share of what is available to us to eat is predominantly ultra-processed. And unsurprisingly, that is then what we're eating, right?

Travis

Yeah, it sounds like that that's just a lot of what we have available and a lot of what we're eating. I guess big picture, what have we learned in the past five, 10 years? What have we learned about how that is impacting us?

Alex

So there was a really nice umbrella analysis that came out in the British Medical Journal around the end of last year. And an umbrella analysis is essentially like a meta-analysis of meta-analyses. I don't know what happens if you do it three times. I think beetle juice appears. But what that means is that it's trying to aggregate a lot, a lot of data. And so a Big problem with this research is that we don't have a lot of the gold standard evidence. And that gold standard evidence is a randomized control trial, right? Where we would take people, random people off the street, and we would put one group on one diet, one group on the other diet. And when you don't have a lot of that, what you're looking for is as much kind of good population level evidence as you can. So if you go out and you ask a bunch of people, hey, what do you eat? And you categorize it, and then you look at their health outcomes. And so that umbrella analysis analyzed over 45 population level studies. just studies kind of within themselves that were thousands and thousands and thousands of people. And what they found were pretty strong links with some things that were kind of unsurprising, things like weight gain and metabolic disease and type 2 diabetes. They also found links with cancer. And then they found links, which I think...with things that we might find a little more surprising. So eating those foods was increasing your risk, like I said, for metabolic disease, for cancer, but also things like for anxiety and depression and for sleep disturbances. And so we actually have a fair amount of population level evidence that these foods are harmful for our health in kind of a variety of domains. And there's also a fair amount of evidence for what we generally call all-cause mortality. So just shortening your lifespan dying sooner than expected, basically. There isn't a lot of evidence, like I said, at this like gold standard randomized clinical trial evidence. There was one study that came out in 2019 that was run at the National Institutes of Health, so just up in Bethesda, by someone named Kevin Hall. And he took people and that was an inpatient study. So it was kind of gold standard randomized control trial, take people off the street and give them the

They lived in the hospital and they got these big trays of food every day. So they kind of had way more food than you would eat in a single meal. And those meals were either made up of minimally processed foods. So all the calories came from minimally processed foods or 80 % of the calories came from these ultra-processed foods. And in that study, what they found pretty shockingly, so they had, this was a crossover study. So it was two weeks on one diet and then you'd be flipped to two weeks on the next diet is when you were on the ultra-processed diet, you gained about a kilo of weight. So, you you're getting close to two pounds of weight over two weeks just from that diet. These foods were matched on macronutrients. So they had the same amount of carbohydrates, same amount of fat, same amount of protein at each meal. It was, you know, not balanced exactly like in each food. And there was a little bit of unbalancing of the fiber, but...It wasn't like the ultra processed food was like really high fat and the minimally processed food was really low fat. No, they matched on macronutrients. And then they found when they gave people the minimally processed diet, they lost that weight. So just that weight. And this was just over two weeks. And they switched people. didn't have like a washout period in the middle. They just switched people immediately over. And when you switch people to that minimally processed diet, they eat less and they gain less weight and they lose weight.

Travis

Well, I know lot of your research has to do with with dopamine and how our brains just interpret these foods. How does my brain interpret an ultra-processed food differently than something that's minimally processed?

Alex

Yeah, so we've done a lot of work and a lot of what my lab is interesting when people ask me like, oh, what does your lab do? I like to say we do nutrient sensing, but in humans, and then that confuses people. But what that means is we're really interested in understanding, for a long time, the field, so if we wanted to talk about, okay, how does your brain control eating, that field gets called a repetitive neuroscience. And for a while, the field of repetitive neuroscience has really been floating head like we've been really interested in okay what happens in the oral cavity, how do we sense sugar, how do we sense fat in the oral cavity, how is that related to the brain, and then how does that kind of change behavior. And there's been less focus on what happens after you eat something. And I should say you know that hasn't been there's been kind of resurgence of this kind of throughout history so you know there's experiments you know back to the the 60s essentially showing if you put in a tube directly into a rodent's gut and you have them press a lever, they can learn to press a lever just for nutrients in their gut. So those systems are important and they can change behavior and drive learning. But what's really exciting and so you know there's kind of a be that little surge of interest in that about kind of this time around of when we've been like yeah we should actually be studying what's happening in the gut is that we have a lot more tools to figure out what's going on. And so that's a lot of what I do is understanding, you have eaten the food, you have all the signaling with taste, but now you actually have a second set of signals that are happening 20 to 30 minutes later when so all you eat your food, it goes into your stomach and your stomach is just like a big bag and sloshes it around, right? And then what it does is it dumps that food into your upper intestine or your duodenum, that kind of first part of your duodenum. And we know from a lot of experiments that there's a lot of sensing that is happening in the duodenum that is saying, okay, now that's relaying that information up to your brain, hey, you just ate a bunch of fat, or you just ate a bunch of carbohydrate. And that's a really important thing for our brain to figure out, right? And so we come out of the box and we like sweet and we reject bitter, right? So basically you can take a very young baby, you can put a sweet solution in their mouth and they'll make competitive responses, right? You can squirt a bitter solution in their mouth and they'll go, and they'll reject it. But the everything else we have to learn, right, every single other eating behavior, every food preference that you have, you have learned over the course of your life. And one of the ways by which we think that has happened that's okay, that kind of general problem is what's known as the omnivorous dilemma. It was posited by Rosen and Rosen way back and then kind of made popular again by Michael Pollan, you might have heard it. the phrase the omnivorous dilemma in the context of his work. But how we solve the omnivorous dilemma, one of the ways by which we can solve it is through this idea of flavor nutrient conditioning, of pairing the flavors and the tastes and the aromas and the sights of food with its useful nutrient consequence. And the ways in which it's different, you know, with an ultra-processed food. So one, if we're talking about true ultra-processed foods in the wild, which I feel like is really different from trying to nutrient match those foods. think nutrient matching foods in studies, super important for understanding, but it doesn't actually capture what those foods are. Because for the most part, if you go to a grocery store, an ultra-processed foods could be high in fat, it's going to be high in sugar, right? Or it's going to be most likely really high in refined carbohydrates and sodium, for example. And those just don't exist in their minimally processed counterparts. can, know, a lot of what we do in the lab is trying to falsely make them equivalent. But We know that signaling in the gut to the brain for sugar and for fat actually goes through different pathways, different peripheral pathways, and then it converges on a single neural signature, that neural signature being dopamine, what you mentioned, this kind of increase in dopamine in this area of the brain called the striatum, which is super important for motivation and reward as well as learning. And because those two different macronutrients arrive through separate pathways, it is possible and we have evidence that actually there's kind of a super additive effect of consuming them together. Because, you in our evolutionary past, we probably only eat them one at a time, right? It's really hard to find like a mentally processed food in the wild that has really high in fat and sugar, right? Like there is no doughnut tree. But we can eat a doughnut now and we get this big hit fat and sugar. And we actually ran a study in humans showing that what that does is we actually, even if you hold, again, try to match number of calories, but vary the macronutrient, people will overvalue those foods that contain fat and sugar in combination, even though they're delivering the same number of calories as a food that was predominantly fat or predominantly carbohydrate, and the brain encodes it slightly differently. You kind of see different activity in these motivation areas. And so that's kind of telling us that this system, it didn't evolve to figure out the caloric content of a doughnut. It's getting kind of conflicting signals. And we've actually been collaborating with Matt Howe here in the School of Neuroscience at Virginia Tech to kind of go back into animals and figure out, like imparse that signal a little bit more and actually record dopamine from rodents who are consuming sugar, consuming fat consuming combinations and we're actually seeing differences in that dopamine signal in those animals. And so again, I wasn't giving you way too long of an answer, but that is the kind of long answer of like what is happening with those ultra-processed foods. And that's part of the reason why we think, I mean, why those foods that are really high in sugar and fat, like those are the ones that are hard to stop eating. Those are the ones that you kind of crave because you get this double hit of dopamine, this kind of double signal. And that is what is kind of biasing your behavior towards, okay, given the choice between something that is minimally processed and ultra-processed, you might pick the ultra-processed one.

Travis

If I was going to just maybe paraphrase that for millions of years, we had food in the wild and it for the most part, like you said, there is no donut tree. So you're getting like something that's got sugar in it or maybe something that's high in fat. And now we have these foods that basically jolt my system with like both of these at the same time. And whether or not I realize it or not, my brain is like, yes, more police.

Alex

Yeah, exactly. I really like that. I like that more, please, because I feel like people, wonder, they're like, what is the dopamine signal? And actually, that kind of really is what the dopamine signal is. It's not pleasure. It's your brain telling you, oh, go do that again. Right? Because if you are an organism that needs to solve the omnivorous limit and figure out what to eat, you need a really good signal that says, okay, go eat that again. Like you found a good food source. Go eat that again because that's what evolution should be putting pressure on, right? Being able to find and exploit good food sources. If you think about, you know, like kind of like the best that we could do even at the kind of birth of the agricultural revolution, like 12,000 years ago, right? Was to be able to get like oats and like honey and maybe, and some sort of full fat milk or cream maybe and combine those. But even doing that, we can't get anywhere close to the macronutrient content of a donut. And then also 12,000 years is a blink of an eye on an evolutionary timescale, right? So we are kind of mismatched in our environment currently, where we have a system that evolved really beautifully to be able to kind of figure out what are the different nutrients in the environment. And now we're exposing it to the stimuli that just never seen before. And it's getting tricked in the same way, you know, that drugs of abuse trick your brain, right, by dialing these systems up even, even harder.

Travis

I saw this fascinating quote from you about stress eating that no one is going to grab the broccoli when they get super stressed out. And I guess that's what's happening is our brains, they're starting to realize this. And then when we get stressed out or we need something to cope with maybe other things that are happening, maybe that's why we go to the chips or whatever we go to, but not the broccoli.

Alex

Yeah, and there are studies showing things like chocolate, especially high carbohydrates, if people eat them and then they do mood ratings of how it increases their mood and it makes them feel better. Those foods do make people feel better. They increase mood and they increase mood to rates that are similar to drugs like nicotine or other drugs that make people feel a little better when they take them. And yeah, we just don't see really the same effects with minimally processed foods.

Travis

I think you mentioned earlier depression and anxiety and how ultra-processed foods might impact. What do we know about how ultra-processed foods impact those areas of our lives?

Alex

Not a lot, actually. So that umbrella analysis, I think really pointed out a big hole in our research because they found actually pretty strong evidence. They kind of graded levels of evidence of what was kind of the strongest relationships and the highest quality. And there was actually some of that strongest relationship with sleep disturbances and anxiety. And we don't actually know a whole lot.

There are some researchers looking into this, essentially trying to take people who have depression and doing food interventions with them, you know, not telling them to stop their other therapy or their other medications, but okay, if we change your diet on top of these other things you're doing, can we actually improve your symptoms even more? And that work hasn't been published yet, but it seems like there are some trends and that you can actually, people do start to feel better when you change their diet. But it's really hard, right? I feel like you can't just go tell someone who has major depression, like, cook more, because that's basically what you need to do to consume less ultra-processed foods. And so you have to think of interventions where people can have mentally processed meals delivered, or what are actually kind of effective interventions to help people.

Travis

So would imagine that would especially be true if your brain has been previously wired to go to these areas to find that hit of dopamine when you're feeling a little down or stressed or whatever.

Alex

Yeah, and I mean, think, you know, we have the idea of comfort foods exists for a reason. And, you know, everything that we're doing is a, you know, it's a process of some way of learning, right? You have learned that if you eat these foods, you know, you feel a little better when you're feeling down. And then also, there's a lot of, you know, I don't want to kind of get rid of the very true thing is that if you want to eat a more mentally processed diet, have to do a lot more work. Like there's either a lot more cost associated with it or a lot more work. And that they take a lot more time to repair to prepare. You know, there's a reason beyond just that the ultra-processed foods, you know, are able to kind of pull some of these levers that mentally processed foods can to kind of make you want them more, but they're also everywhere, right? And they're shelf stable and they're easy to prepare microwave them, know, they're literally everywhere. And so that's something driving their intake also that we can't really ignore. But it is when you're talking about interventions for people, it becomes very, very difficult to tell someone, eat less ultra-processed foods, right? When they're everywhere in their environment.

Travis

Well, that's a great segue to a question that I'm really curious about with you and your research. There is not a single person in my life that I can think of right now, regardless of age, gender, anything that doesn't constantly, I feel like, talk about food choices, where they're always navigating food choices. And so I'm curious how you, being in this field and do this research, how do you navigate this landscape of ultra-processed foods?

Alex

Yeah, it's really, I mean, it is very, very difficult. And so, you know, I've talked about, you know, something like 73 % of the food supply. But if you look at like, let's look at advertising on TV, nobody's advertising blueberries, right? Nobody's advertising you like things that are healthy for you, right? Basically non ultra processed foods, because they aren't produced, you know, but they don't have a brand name. They don't have these things associated with them. It is super, super difficult to make these food choices in our current environment. Then if you look at people who might be having trouble trying to stop eating these foods, there's advertisements for food on a little video screen when you pump gas. The checkout lines are stacked with ultra-processed foods, so you have to walk through all of them for you even to check out of the grocery store. Then also, I think a lot of times, a lot of foods are marketed as healthy or good for you, but are actually ultra-processed. You see this a lot in lot of kids' products that are advertised as like, they have vegetables in them. But you you look over and turn the package over. It's like mainly potato starch and like some, you know, a little bit of like spinach powder to make something green, you know? And so we're the, everybody is being inundated with either bad information or signals that are biasing you towards consuming ultra processed foods. And so for me and my family, I mean, I'm not like one of these people who's like, I have never touched a dino nugget. I have never touched, you know, the box of mac and cheese. No, like for the most part, I think I do what a lot of people do and what a lot of parents do is there's kind of this mental arithmetic in my head. I'm like, okay, if 80 % of the time we can eat a minimally processed diet and 20 % of the time, we can make the box mac and cheese or send the processed snack to school or eat the processed food, we'll be fine. That to me feels like a good ratio. I think the problem that is The thing that is really difficult is as you're trying to maintain that ratio, you're just being inundated with signals to eat the 20%, and none to eat the 80%. And also those foods that kind of should be in your 80 % bucket are just harder. They take longer to cook, harder to make. They take time and equipment. And so yeah, it's really hard. I still eat all sorts of ultra processed things, but...I do try to kind of maintain that balance of, right, you know, I think we know that that number of 58 % of calories consumed from ultra processed foods is probably a bad number. We don't know what the number is, right? There is no study doing some sort of dose response to figure out, okay, 30 % is fine, but 35 is not, right? But for me, broadly thinking, okay, if we can bring that down to somewhere closer to 20%, then we're probably, you know, gonna be much healthier.

Travis

So maybe a good goal for us is if we can limit the amount of food shaped like dinosaurs we're eating to 20 % or under, we're doing okay.

Alex

And yeah, I feel like that number is probably maybe even a little higher. And so if you shoot for 20, you you mess up some, like you'll be fine.

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Travis

And thanks to Alex for helping us better understand ultra-processed foods and the challenges in navigating our current food and landscape. If you or someone you know would make for a great curious conversation, email me at traviskw at vt.edu. I'm Travis Williams, and this has been Virginia Tech's Curious Conversations.

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