Sugar & Sweeteners: Are They Really Addictive or Unhealthy? | Nicole Avena | #185

About the guest: Nicole Avena, PhD is a neuroscientist at Mount Sinai. She studies the effects of sugar and diet on animal behavior and the brain. She is also the author of, “Sugarless.”

Episode summary: Nick and Dr. Avena discuss: drug addiction vs. food addiction; glucose, fructose & artificial sweeteners; the extent to which sugar consumption can drive dependency & withdrawal; fructose metabolism & live health; sweetness & palatability; ultra-processed foods; and more.

Related episodes:

* M&M 140: Obesogens, Oxidative Stress, Dietary Sugars & Fats, Statins, Diabetes & the True Causes of Metabolic Dysfunction & Chronic Disease | Robert Lustig

* M&M #134: Omega-6-9 Fats, Vegetable & Seed Oils, Sugar, Processed Food, Metabolic Health & Dietary Origins of Chronic Inflammatory Disease | Artemis Simopoulos | #134

*This content is never meant to serve as medical advice

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* Episode transcript below.

Full AI-generated transcript below. Beware of typos & mistranslations!

Nicole Avena 1:29

So my background is that, well, I guess I should start with where I am now. So I'm a associate professor of neuroscience at Mount Sinai School of Medicine in New York City, and I'm also a visiting professor of psychology at Princeton University. My background is that I am interested in how the brain is affected by the foods that we eat. And I started off on this journey when I was a grad student at Princeton. I worked there for my PhD to study neuroscience and learn about the brain, and our lab since then has been focused on this idea of food addiction and trying to better understand our modern food environment and how the different foods that we engage with these days are affecting our brains in ways that are perhaps not good for our health and can be contributing to Addictive overeating. So that's essentially what we've been looking at and thinking about in my lab, and what I pretty much think about all the time.

Nick Jikomes 2:35

Okay, so when we talk about addiction, you know, it's a subject I've covered before on the podcast, but you know, for those who haven't learned too much about this, maybe let's start with drug addiction and then talk about the extent to which, you know, there is such a thing as food addiction, and foods, you know Do or do not behave like addictive drugs do. So from the standpoint of an addiction biologist, when we think about drugs of addiction, right? What is addiction? How do you define it and what characterizes it?

Nicole Avena 3:01

Yeah, it's an important question, and I spent a lot of time, especially early in my career, looking at that very question, because when we think about what is an addiction, we have criteria that we can apply. So the American Psychiatric Association in their Diagnostic and Statistical Manual of Mental Disorders, the DSM lays out the criteria that need to be met for what's referred to as substance use disorder. And it's important to keep in mind that this is a spectrum, so you can have mild, moderate or severe substance use disorder, and so depending on what your substance is, that may or may not be terrible, right? So obviously, if you have, you know, a major substance use disorder for something like heroin, it's going to potentially cause you to, you know, overdose, and you're going to have a lot of problems. It's an illegal substance. But if you have, you know, major addiction to caffeine, and you're just drinking coffee all day long, then maybe it's not going to be so bad. So it really depends on the substance and the severity of the substance. So what we've been doing essentially, is taking these criteria for addiction, and there's a variety of different categories of criteria, some of them are, you know, based off of the way in which the substance works in our bodies. So you know whether or not you experience tolerance to the substance, whether or not you experience withdrawal signs if you go off the substance. But some of them are also social constructs. So you know some of the criteria for addiction are built around whether or not you know you could miss work because you're using the substance. And obviously you could bring coffee to work so you don't have to miss work to use coffee or caffeine, but you can't bring other things, you know, to work all the time that maybe people are addicted to. So the criteria, again, there's room for discussion there. I think, I think those could be better defined, but that's another topic. Yeah, but in any case, how does food fall into this? What we've been doing is basically taking those criteria, and we've conducted experiments, both pre clinical and clinical, to basically just test whether or not Ultra processed foods, or sugar in particular, can produce those criteria that are associated with addiction. And you know, much like there's plenty of drugs out there that aren't addictive, there's plenty of foods out there that aren't addictive. But what we've been finding is that the foods that are considered Ultra processed foods that have excess amounts of sugar in them seem to fall into this category where the DSM criteria for addiction can be met when the substance of abuse is that food.

Nick Jikomes 5:42

So, you know, when we think about addiction, we can think about it behaviorally. We can look at what animals or humans do in response to consuming certain substances. People often talk about, you know, dependency and compulsion. Dependency, basically being in the absence of the thing that you're addicted to. There's some kind of withdrawal symptoms. You feel bad because you've, you've become dependent on it, and then compulsion being, you know, how strong is the pull to consume the thing? Will you want to go consume it, even at the expense of doing other things that are, you know, normal or adaptive in your life? And then, you know, the other way we can think about this, which I'm sure we'll talk about, is the actual effects on the brain. How do different parts of the brain light up? What are the mechanisms involved in response to consuming certain substances that are addictive, and how does food look in comparison to drugs of addiction? So when we think about this behaviorally in terms of what animals do, the compulsion, the dependency side of things, can you start off with just talking a little bit about what are some of the clearest examples of a food that drives addictive behaviors, akin to what we see with addictive drugs. Yeah,

Nicole Avena 6:46

so in terms of the behavior, which is very important, because that kind of lays the groundwork for further exploration in terms of the brain mechanisms, what we've seen is many of the behaviors that you would see in animal models, where an animal is, you know, dependent on alcohol, for example, there's certain behaviors, seeking behaviors that they'll engage in that we also can see happening with sugar. So, you know, again, things like building up a tolerance, so needing to consume more and more of the substance in order to get the same euphoria or satisfaction that you used to get from having less of it. That's certainly one of the behaviors that we've seen. Also, like I mentioned a bit earlier, withdrawal, if the substance is not available for a period of time, then we are able to see both clinically pre clinically signs of withdrawal emerging, and what this looks like when it comes to food is similar to what it looks like with tobacco or what it looks like with caffeine, where, you know, depending on, you know, the severity of the dependence, people can experience feelings of irritability. People might feel weak or lethargic, and again, you know it's going to vary depending on the individual, and you know how much of the substance they've been consuming and for how long. And then, in terms of cravings, that's also another behavior that we've been able to capture. In terms of the research, we've seen that an animal models animals are willing to work harder for longer in order to get access to a substance like sugar or ultra processed food. And that's similar to what you would see if an animal was dependent on nicotine or, you know, on morphine, even where they're willing to lever press, you know, 5000 times in order to get a little hit of it, whereas if it was a different substance, it wouldn't be worth it, right? So they wouldn't even bother liver pressing to get access to it. So that willingness to work is is a key. Because even though we're seeing this in animal models, we also, you know, can see it in humans as well, in the sense that people will articulate to us that they crave certain types of foods, people don't typically say, Oh, I'm craving, you know, broccoli. But you know, when they are especially in an emotional, dysregulated state, like stressed or anxious, they tend to experience a desire for foods that will satisfy them. And again, that's related to the brain mechanisms, yeah.

Nick Jikomes 9:20

And I suppose a key thing here is that we whether it's the dependency and withdrawal side of things or the compulsion the seeking side of things. We're, you're seeing this behavior, it sounds in for certain foods and not others. And by analogy, you know, we see this. We see this type of thing for certain drugs, but not others. Animals work very hard and exhibit cravings for cocaine at a rate that's much higher than say, you know, LSD or whatever,

Nicole Avena 9:44

right? Exactly, yeah, and that's where it gets tricky, because when we a lot of this, you know, in hindsight, it's one of those things where you are regretful of calling something something, right? Because when we first started publishing about this work, we were. Using the term food addiction, because we were looking at food and seeing that some of it's addictive. But what's happened now is that, you know, yeah, not all food is addictive. So, you know, the terminology has morphed a bit, and some scientists will talk about Ultra processed food addiction, which I guess is a better way to characterize it, although it's kind of a mouthful, but one thing that I kind of think, and perhaps we could get into this in a few minutes, that is almost a solution that would help a lot of this would be if we had a different category for these different types of foods. I don't necessarily think the term food should be this ubiquitous umbrella. It encompasses everything from carrots to pop tarts, because Right, right, very big differences between those things. So that's where I'd like to see, you know, some changes in terms of how we think about this from the addiction side, for sure, but we also need to think about, well, what is a food?

Nick Jikomes 10:54

And one thing I want to adjust up front for for listeners too, is when we talk about addiction, even if we're talking about drug addiction, a drug can be highly addictive. That doesn't mean everyone who's exposed to it becomes addicted. Even highly addictive drugs like, say, cocaine, only, usually a minority of individuals in a population, whether it's rats or mice, whether it's humans, will actually become compulsive drug seekers after multiple rounds of consumption. And so I just kind of want to say this up front when we think about food, because, you know, a lot of people will say, well, sugar can't be addictive. No, I don't know anyone who's addicted to sugar. I eat sugar. I don't have a problem with it. But I think important thing to emphasize here is, if something is addictive or has an addiction liability, that does not mean that everyone exposed to it will become a compulsive seeker of it

Nicole Avena 11:41

absolutely and, you know, just like people can occasionally, you know, smoke cigarettes or occasionally drink alcohol, then just not consume it. It's the same with food. And I think part of the issue, though, that we see with food and not with things like drugs and alcohol, is that we know where the drugs and alcohol are, right? You know, when you go in your refrigerator, if you grab a beverage, whether or not it has alcohol in it, and you have control over that, if there was little bits of tobacco, you know, nicotine sprinkled and, you know, everything that we eat, then I have a feeling a lot more people would be addicted to nicotine because they're consuming it unknowingly. That's what's happening with sugar, right? So when you look at our food supply, when you look at the processed food, which we are reliant on, you know, there aren't enough farms to feed all the people. So I'm not saying we shouldn't have processed food, but when we look at the ingredients, there is sugar in so many of these food products, and the vast majority of them, and often people are consuming it and they don't even realize it, yeah. And so I do think that what does make sugar different from the addiction standpoint, is that more people are at risk for getting that addiction, or developing that addiction just simply due to, you know, the fact that they're exposed to it so much more than other drugs and alcohol.

Nick Jikomes 13:06

Yeah, the sugar is often, you know, effectively camouflage. There's not necessarily a big label that says this much added sugar. And I'm sure we'll get into some of the, yeah, the tricky techniques that are used to sort of hide the true amount of sugar and things. Before we get into some of that I want to talk about. Let's talk about sugar addiction and the evidence. Supporting that it is, in fact, can be addictive. But when you say sugar, what exactly do you mean? Are you talking mostly about glucose, fructose? Does it depend? How do we start to unpack that? You

Nicole Avena 13:34

know, I when I talk about sugar, I'm mostly talking about pretty much anything that's sweet. To be honest, we started off looking at sucrose as the primary sweetener that we were studying, but we've looked at other sweeteners, high fructose corn syrup, and pretty much all the other ones that are out there. And what we're finding from the research is that it's the sweet taste that seems to be driving that addiction, like response. And so you know, when we do studies, and we've done lots of studies looking at the brain, what we see happening is that when sugar is consumed, it can release dopamine in the nucleus accumbens and other areas of limbic system. That is the same pattern of release you'd expect to see with something like a drug or alcohol, and you don't typically see that with food. Normally, when an animal eats something, it doesn't release dopamine in the brain. It will if it's a novel food, and it's the very first time you've ever tasted that particular type of ingredient or that particular cuisine, because it's more of an orienting response where, you know, it's a survival mechanism. We're kind of built to be wary of new tastes, yeah, because when we evolved, it meant if you tasted something funny, it could kill you. So

Nick Jikomes 14:50

there is an aha moment for animals. We're like, Ah, I can eat that. It is okay, yes.

Nicole Avena 14:55

So what's interesting though, is that, you know, when we look at the brain. Yet, most foods don't release dopamine, but when we look at Sugar, it does, and it's interesting, because it often does depend, too on the amount of sugar that's being consumed. When we're looking at a bolus of sugar being consumed, that's going to release dopamine, whereas, you know, occasional sips of sugar here and there don't have that effect on the dopamine system. So it's almost like we've used the term binging. I've gotten away from that because there's such clinical ties to the term binging. It's just really excessive consumption of sugar that causes this dopamine release, and that's what's happening. You know, for most people, most of the time, is that they're releasing dopamine in response to eating those cookies or eating, you know, whatever the substance might be that they're eating. And so I think that's really, you know, a big issue that we need to keep in mind, in terms of the fact that, you know, these foods are affecting the brain in this way, and it doesn't stop at dopamine. I mean, we've seen changes in the endogenous opioid system, the endocannabinoid system, again, all of which basically parallel what happens when you look at the brains of animals that are addicted to drugs or alcohol. And

Nick Jikomes 16:10

so if you put animals in a paradigm, the same paradigm you put them in to assess the addiction liability of a drug, they they exhibit the same basic behaviors in response to sugar. Can you? Can you? Just give us like a concrete example of that? Concrete

Nicole Avena 16:22

example of that? Yeah, so are you talking about from like, the neuroscience standpoint or from the behavioral standpoint?

Nick Jikomes 16:31

Well, let's, let's take them one at a time, but starting with the behavior. Okay,

Nicole Avena 16:35

so yeah. I mean, when we do our studies, like, I'll tell you, we started off looking at developing develop an animal model to study this. First of all, because when I started doing this work, it was the year 2001 and I had just joined the lab at Princeton, and I was talking with my advisor at the time about what we might study. And you know, just through some discussions, this kind of came to be to ask the question, well, could food be addictive, just like drugs and alcohol are addictive. And it came out of the fact that obesity, we were starting to hear more and more about it in the media as a public health concern. And you know, to me, it just didn't seem that it could all be about personal responsibility and it could all be about, you know, willpower, which was kind of what the mantra was back then. And looking at our changing food environment, we started to kind of see, well, there's a lot more sugar in our environment than there was 30 years ago, and now there's a lot more obesity than there was 30 years ago. So perhaps that has something to do with it. So when we developed this animal model, we basically wanted to assess, you know, whether or not binging, withdrawal and craving, which are kind of like the triad of behaviors associated with addiction, would emerge in response to animals that are just binging or given daily access to large amounts of sugar. And so we gave them a sugar solution. They always had water to drink too. So they were never forced to drink it for hydration. They always had food available, so they were never forced to consume it, just for nutrients. And what we ended up seeing was that, in fact, the animals that had this extended access to the sugar solution would develop binging. They developed signs of tolerance. So, you know, they would have larger, larger binges throughout the day, they'd also show signs of withdrawal, and this was measured using measures of depression. We also use the elevated plus maze to assess anxiety, and we also had somatic indications that we were assessing like, you know, changes in blood pressure, changes in body temperature, and even just like ultrasonic vocalizations of distress, essentially that they can be to each other, that we can pick up using different devices. And then lastly, the craving part, that really, you know, can be measured in animals, even though they can't tell us they're craving something, we can do different experiments to see how hard they're willing to work to get access to a substance, and that's usually an indicator that they're craving. So we use opera conditioning to do that. And you know, essentially, what happens is that, you know, we're able to demonstrate these behaviors in animals that are having this excessive consumption of sugar, but not in animals that are eating regular rat Chow, or animals that are having sugar just occasionally,

Nick Jikomes 19:25

yeah, I guess one of the keys here is that you said they always had access to plain water. They always had access to other foods. So they can opt in to doing this. And even though they have that option, and it's not necessary for them to hit their nutrient or water requirements, they often will choose to do this. And the binging becomes more frequent, it becomes bigger. And you can essentially, you can essentially measure things like a mouse sugar hangover, yeah,

Nicole Avena 19:49

basically, that's what, what we've been doing. And, you know, also in people too, because there's been some scales that were developed, and ways in which a lot of the work that we started off doing in our. Or animal models, could then be translated into humans. And so many of these things can now, you know, and again, with the use of neuroimaging techniques, we can basically see this happening in humans as well. And I think one of the things that you know, for me, is so exciting, is that we're able to, you know, capture a lot of what's happening in the brain, because a lot of times behaviors, yes, they are indicative of what's going on in the brain, but to be able to really see these neurochemical changes happening in real time, because a lot of the techniques that we were using at the time of these initial studies were in vivo micro dialysis technique, so that basically allows us to cannulate the rat in the brain and extract extra cellular fluid while the animal is awake and moving. So they're basically running around the cage, tethered so that we can collect the sample from their brain. And they're eating, they're drinking, they're, you know, engaging in whatever behavior they like. And so to be able to see the rat drinking sugar, and then look over on the screen and see a spike in dopamine, I mean, it's really telling to see that happen.

Nick Jikomes 21:13

Yeah? So basically, you see all these behavioral signs the animal is is, in fact, becoming dependent or engaged in compulsive behavior. And then you're saying basically, what you've said so far is that you can see in the brain that the consumption of sugar by rodents is eliciting the same types of effects and same parts of the brain that you would see in response to an addictive drug. Yep,

Nicole Avena 21:33

absolutely. And you know, when you say it like that, it kind of sounds like, Oh, yeah. That makes a lot of sense. But I have to tell you, when we first were doing these initial studies, like when I was a, you know, early grad student, I would go to conferences and present some of our new stuff. It wasn't well received, and it was really just, it's really been over the past, I'd say, 10 years or so, that this concept has really gained a lot of traction. And I think, again, it has to do with the fact that, you know, we used to silo things so much like, addiction was over here, obesity was over here, and nobody really put the two together. But I think now we've gotten a bit more integrated in our thinking when it comes to medicine. And, you know, now, like addiction, medicine is something that people can become certified in when, you know, apply that to obesity and apply that to, you know, treating individuals who are struggling with their body weight. So I do think that, you know, we need to keep in mind that, yeah, I mean, there's been a lot of changes that have happened that have, I think, allow this to gain more acceptance, and hopefully that'll continue.

Nick Jikomes 22:42

And so in the experience you've described for animals, are we talking about when you say sugar water? Are you talking about sucrose here? Yeah.

Nicole Avena 22:50

So our studies initially, you know. And again, because we were trying to be careful scientists, we wanted to make sure that when we were using this model to test all these different aspects of substance use disorder or addiction that we were keeping things aligned. So we were using, typically, a 10% sucrose solution, and that's about the concentration that you would get of sugar in a can of soda, if you would have so that was where we started. And like I said, we've, we've kind of looked at other sweeteners, and we've published looking at high fructose corn syrup. We've looked at glucose at the end of the day. It really does seem to boil down to that sweet taste. One of the studies that we did we used sham feeding combined with in vivo micro dialysis. So what we did was we cannulated the stomach of the rat so that when they would drink the sugar solution, they wouldn't digest it. It would simply exit through the stomach, through a tube. And when we were to do micro dialysis on those animals, while they were sham feeding sugar so they could drink it, taste it, but not digest it, we saw that it was causing a release of dopamine, even though they're not digesting it, so just simply tasting the sugar was enough to elicit that dopaminergic response, and even with other sweeteners that have been tested, the whole sweetener world is a little tricky when it comes to rodents, because some rodents don't even detect the taste of Certain artificial sweeteners, just because they're so artificial they like,

Nick Jikomes 24:23

they don't have, like,

Nicole Avena 24:23

receptors for it, yeah, they just, they know to stay away. But yeah, so to me, it's, it's really more about the sweet taste. Now it goes beyond the addiction, right? I mean, obviously there's certain types of sweeteners, like fructose is going to have more of a negative impact on the liver than, you know, maybe other types of sweeteners would. So there are differences, for sure, terms of how these sweeteners affect the body, but you know, just coming from the addiction piece, it's really about the sweet taste.

Nick Jikomes 24:52

But yeah, so what you're saying is, if you sort of regress all the variables here, it's the level of sweetness is proportional to the level of C. King that you're going to get from the animal Absolutely.

Nicole Avena 25:01

And, you know, I think that's when we look at this from the public health perspective. I mean, that's the problem. Is the level of sweetness has just been slowly getting ticked up. And if you look at the amount of sugar that's in all the different food products that are on the market, it's so much more now than it was five years ago, 10 years ago, you know, going back, you can really see it. And then just the sheer number of products that have added sugar has gone up. So, you know, there's just, you know, I like to think about this from, you know, what are we going to see in 20 years? Because, I mean, there's sugar in so many of the different things that kids are eating, they're basically being raised to have this high level preference for sugar that, you know, basically means that they're going to desire to have things be really, really sweet. So it means they're going to be consuming more

Nick Jikomes 25:55

and more of it over time. Yeah. And, you know, one of the things I want to ask about here too is, well, if I step back for a second, I think about, sort of, why all of the biology is set up this way. And you know how things work under naturalistic or ecological scenarios? You know, if I think about addictive drugs, it's pretty it's pretty easy to think about, it's like, okay, the brain needs to have mechanisms to motivate the animal to do things. It needs to have natural forms of reward processing to tell it like, go for this, don't go for that. You know, develop preferences, develop motivations. And it's not surprising that, you know, you see substances like synthetic compounds that have, you know, super sized effects in this natural reward circuitry in the brain. You know, whether that's a psycho stimulant or an opioid or something, you're like, Okay, it's tapping into natural mechanisms that are for reward learning, but it's got a super sized effect effectively, because it's not, it's not ever anything that an animal is going to encounter in nature. And when it comes to something like sugar, sugar is, of course, something that animals encounter in nature, and so but they're still developing these addictions, as you've just told us, is the way to think about this, that in nature, the dose and the frequency with which an animal will encounter something like a natural sugar reward is limited, whereas in artificial settings concocted by humans, that's not the case. Yeah,

Nicole Avena 27:17

absolutely. And you know, if you think about it, if an animal, or even us as humans, if we were to wander into an apple tree, right? Are you going to eat the whole tree worth of apples? No, we have satiety mechanisms built in where, you know, there's fiber in the apples, and we get full from the calories, and so our jaws get tired from having to masticate the apple to chew it up. So we have these sort of built in breaks, if you will, to slow us down, to stop us from over consuming so that limits the amount of sugar that we have, and also just nature in and of itself. I mean, the world isn't covered in apple trees. You have to find one. It has to be during the proper season. It has to be, you know, something where the Apple hasn't fallen off the tree and it hasn't spoiled. It has to still be, you know, safe and attached to the tree. To

Nick Jikomes 28:10

do work, to find it, you might have to fight for it. You've got to chew it. It's not a liquid bolus of straight sugar, exactly.

Nicole Avena 28:16

And I think that's, you know, really, what we're facing right now is that, you know, a lot of the work is taken out. I mean, again, it's wonderful that we have refrigeration and we don't have to, you know, plan our own apple trees. But it does mean that, you know, we get access, and the amounts of it, I think, you know, in terms of taking an apple, let's say, and then, you know, making apple juice, yeah, you can, you know, how many apples would you need to make a glass of apple juice? Right? I mean, that's quite a few apples. No one's going to sit there and eat all those apples. But again, we're bypassing a lot of the barriers that biology has put in place, whether it's from nature or whether it's just from, you know, satiety mechanisms. When we take a look at a lot of these processed foods, and that's what makes them so easy to over consume, and that's what makes it, you know, very dangerous. We weren't designed to have that much sugar. Our bodies, again, were built differently and have not been able to adapt to have the ability to put on the brakes when it comes to these processed foods, just because it's come on the scene so quickly. Yeah,

Nick Jikomes 29:29

and I think this is important, there's a lot of different satiety mechanisms that come into play at different timescales, but in nature, these things are sort of all stacked on top of each other in a way that we've just gotten around through being able to engineer our own foods. And I think it's important to really emphasize this. One of my biggest pet peeves that certain types of people bring up in this discussion is, you know, people will sort of cherry pick from the ethnographic record. They'll say, What about the Hadza people? They eat 60% of their calories from honey, blah, blah, blah, blah. Lot, and it's like, well, yes, but they also have to climb a tree and then fight off bees to get the honey. They eat it with the waxes and the larvae. And it's seasonal, so there's, there's always baked in limitations, right?

Nicole Avena 30:10

Exactly. And, you know, again, I think we also need to keep in mind like, yes, what we're eating is important, but, like, you're suggesting, you know, there's a lot of other stuff that contributes to, you know, stressors in our environment that you know can lead us to, then want to overeat sugar, you know, that's one of the key components, I think, that often doesn't get discussed. We have a lot of other things that contribute to, you know, what we eat, and you know how that's going to have an impact on our body? You know, if you're an ultra marathon runner, like you probably could get away with eating more sugar, and, you know, having a lot of these things, compared to somebody who maybe is, you know, very sedentary or just has a regular office job and doesn't really get that much exercise. So it's, it's all, like you said, Yeah, I do not like the cherry picking either, because it leaves out the whole, like holistic aspect of this, that this is, there's interconnected components that we need to keep in mind. And

Nick Jikomes 31:13

I guess this relates to the question, a sort of a similar question that I often see out there, in the in the in the zeitgeist here, which is, you know, sometimes people will make the argument, glucose can't possibly be bad for you. Sugar can't possibly be bad for you, because, even, seeing, all organisms are designed or evolved to use glucose as a fuel source, it's efficient substrate for ATP production. So, you know, it can't be bad for you in any context?

Nicole Avena 31:40

Yeah, I've heard that. And, you know, anything could be, I mean, that's like saying, like, if you just keep putting gasoline in your car until it's covered, you know, leaking out that how? How could that be bad for your car? Well, yeah, that's just because the car was only designed to hold a certain amount of gasoline. Same with our brains and our bodies when it comes to sugar. I really don't think we were designed to, you know, have products that we're consuming that have, you know, 50 or 60 grams of sugar in one serving. You're never going to find that every

Nick Jikomes 32:19

day all year. Yeah, exactly.

Nicole Avena 32:21

And so, you know, I think we need to keep in mind that, you know, yes, we our body uses glucose as a fuel, but our body can make glucose as a fuel. We don't need to eat it in order for our body to make it. And so I think that, you know, there is a bit, I think, of miscommunication out there around actually how much sugar we need to survive. There's, there's plenty of people who really hardly eat any sugar. Look at all the people who do like hardcore keto, for example. You know, they might not be consuming carbohydrates in a meaningful way, but they're still alive and walking around, because their body is going to produce the glucose for them. Now, I'm not advocating, you know that as a long term solution, but it just proves the point that, you know you don't need glucose in order to survive, because I think that you don't need to eat it. Exactly, yeah, and you certainly don't need to eat, you know, 50 grams per serving of it.

Nick Jikomes 33:22

Yeah, yeah. One of the things I want to talk about here, we'll get into things like individual differences, differences between the response to sugar consumption and say, obese for this non obese people. But I guess sort of the larger point here is, if we look at the drug addiction literature, what we find, again, as we said before, only a subset of individuals will end up becoming addicted and displaying all the hallmarks of addiction after exposure. Some won't display those things even after exposure. And you know, even even when you look at the initial brain response the very first encounter with an addictive substance like cocaine, say, some individuals will have bigger responses in some of this dopamine reward circuitry than others. And you know, for reasons that are still mysterious, we don't really know where those differences arise, but there are differences between people that will just, you know, make one person more prone to have a rewarding response to something, whether it's a natural reward or a drug reward, than than other people will. And so I'm wondering if you could talk a little bit about individual variability here, maybe brain responses, and, you know, the obese versus non obese individuals, things like that. Yeah.

Nicole Avena 34:30

So genetics certainly plays a role. We know that, you know, certain people just have a genetic propensity to become dependent on things, compared to others who maybe perhaps don't have that genetic propensity. Another thing that I think is important to keep in mind, and I mentioned this a little bit ago, is the stress component. You know, sometimes stress can be the sort of thing that pushes people over to utilize. Is a substance in order to combat stress or to combat anxiety. And so people who, for some reason, have you know the less of an ability to manage stress or to cope with stress, or have coping skills that have been employed to help them mitigate their anxiety and stress are at greater risk for developing an addiction and utilizing these types of substances like drugs or alcohol. And then, you know, I think individually, when we think about, you know, why some people get addictions versus why others don't, I think we also need to keep in mind history so aces scores that's advanced, excuse me, adverse childhood experiences. There's a lot of research that suggests that individuals who have higher aces scores are more likely to develop addiction. So you know, acknowledging that there is embedded trauma that can then manifest itself later in life, and sometimes that takes a form of developing an addiction. So I think all these things, you know, we can easily think about when it comes to addictions to drugs. And I also, too, think that in many cases, you know, these apply to food. But what's again, different, I the I will argue, is that, I guess, because of the availability of sugar, and because of the early exposure to sugar, more and more people are at risk for developing that addiction. Also, one thing that we should also bring up is this idea of cross sensitization, and so if you have a history of drug use, you're more likely to get dependent on a

Nick Jikomes 36:42

new drug because they all tap into the same core mechanism Exactly,

Nicole Avena 36:46

exactly. So that's why you know people you know will sometimes, like, warn their teenagers, like, Oh, don't you know if you smoke marijuana or if you smoke cigarettes, you're more likely to then, you know, get into harder drugs later on, on this whole, like gateway effect idea. And there's some truth to that, because, again, you're, you know, activating the brain reward system with these substances. And at some point that might max out, or someone might say, Oh, let me try this other substance for something different. And then, you know, it goes from there.

Nick Jikomes 37:20

And so yeah, and people get really strong opinions when it comes to this stuff. But what's, I think, what you just said is, what is incontrovertibly true is that, you know, any, any substance that can be abused will ultimately tap into the same, you know, dopamine based reward circuitry within the brain, and that circuitry itself becomes more sensitized with and develops tolerance to, you know, any one of these substances, and that can lead to a future increase in the likelihood of being sensitized to another one if you engage in consumption of that other thing Absolutely. And,

Nicole Avena 37:54

you know, I've talked with I gave a presentation to drug free America Foundation a bit ago, and one of the things that they wanted me to speak about was, you know, they have done a really good job of educating people about the dangers of drug use, but a problem that they face is that often people stop using drugs and develop obesity and end up eating and end up having diabetes. This is something you see happening, you know, just on a smaller scale for with people who are smokers, who stop smoking, they usually wait. And you know, part of that is because the brain has been sensitized to still want that reward. And since you're not getting it from nicotine or drugs you naturally

Nick Jikomes 38:42

seek to get it somewhere else.

Nicole Avena 38:44

You can get it from sugar, you can get it from processed food, and it's safer than the drug that they were abusing, at least. That's the, I guess, the way they view it, um, it's acceptable, it's ubiquitous, it's cheap, and it's, you know, not viewed as necessarily something that is bad for their health. And so that, again, underscores this whole concept of how cross sensitization does play a role.

Nick Jikomes 39:12

Yeah, and I wonder, so when we talk about the palatability of foods and the potential addictive effects that things like sugar can have. How does this tie into things like the obesity epidemic at large? So I would imagine, you know, so when we consume, when most people can consume sugar, it's usually not just straight sugar. They're not just taking a, you know, a scoop full of sucrose. They're not drinking, literally, a bottle of high fructose corn syrup. It's really these sugars added into other things. And so to the extent that that palatability is higher due to the presence of the sugar, to the extent that they become addicted, basically they're going to naturally be consuming more overall calories, right?

Nicole Avena 39:52

Absolutely, yeah. And I think that, you know, sugar is sort of the siren that. Stores people in, right? It's the thing that is, it's the tasty component to the substance that's being consumed. But with that comes additional calories. With that comes other ingredients that are added that maybe in and of themselves aren't necessarily like desirable or palatable, but they contain things that are going to add extra calories or add saturated fat or add, you know, things that aren't going to be healthful for us. Yeah, so I think it's it, you're right. It's not sugar that you know. But I think we need to keep in mind that, you know, we're we're designed to have, like, a a threshold of sweetness. And so children's threshold for sweetness is actually higher than adults. And so that's why kids cereals tend to have lots of sugar added on them. And kids always want things to be sweet, because they are actually living in a very different sensory world than adults. Are they actually the threshold for sweetness of what they prefer is higher than adults. And you know, it just goes to show, though, that, you know, it has to be calculated in such a way that it's palatable. It's kind of like an inverted U in the sense that there is this sort of optimal bliss point of sweetness. If you go below that, it doesn't taste that great. If you go above that, it's going to taste aversive. So things can be too sweet. And so that's why it is usually sugar added with other ingredients, so that it's not just, like 100% sugar that's doing things. Yeah, because

Nick Jikomes 41:30

I would imagine naturally, if there, if it wasn't an inverted U relationship, if it was truly linear, like, more sweetness equals more consumption than all of the food companies would simply be putting hundreds of grams and everything. Yeah, we

Nicole Avena 41:43

would be investing in the Domino Sugar Company, right? Because people would be, you know, popping sugar cubes all day. And no one is really doing that. Um, but it is, yeah, there is sort of this, but it's creeping up. And I think that's the thing. And I think what do we we are seeing is that, you know, the increasing amount of eating occasions that are happening does contribute to this as well. So if people are eating, you know, boluses of sugar that maybe they don't realize in terms of the portion size, or, you know, just in terms of the other ingredients that are in the product multiple times throughout the day, for many years, over time, over time, that's really going to add up and have a negative impact on their health.

Nick Jikomes 42:27

So, so, you know, we've talked about how sweetness is, is sort of a major component here. It's really the sweetness people are attracted to. Different sugars have different levels of sweetness. But ultimately, you know, we can think about, we can, more or less think about this in terms of the, you know, if something has an optimal level of sweetness, it's going to be maximally reinforcing. But other foods are also very tasty. I love the taste of many high fat foods that are very low in sugar. I love the taste of very savory foods. There's few things I like more than than, you know, the right cut of steak. How come we don't hear about those things driving this kind of compulsive seeking behavior?

Nicole Avena 43:07

I think it has to do with the fact that, you know, again, when we talk about things like, for example, steak, you know, it's, it's processed in the sense that you usually cook it a little bit right to make sure it's safe to eat, but it's, I think, more about the number of ingredients, and, you know, the ultra processed nature. Also, there's, again, going back to what we're talking about a bit ago, you know, we have these satiety signals that are built in when you consume a steak. You know, you have to chew it. It's you gotta cut it up. It's going to cause you to feel full after you eat it. And we see that isn't really happening with these processed foods, with the foods of the added sugar, because most of them do not have a lot of fiber in them, and there's really nothing that's pausing us to want to stop eating them. There's no barrier that is put in place to have people, you know, basically become satiated. And you know, if you think about this, sort of like balance of, you know, desire for reward and satiety, usually, you know, when you get some satisfaction, you have satiety going up. And that's kind of allows you to, you know, sit back and enjoy it, and then, you know, maybe get some more later on, if you get hungry again or want more reward, but if you have desire with no satiety mechanism in place, you know, there's nothing to stop people from just consuming until it's gone. And I think that's what's happening with a lot of these sugary foods and a lot of these highly processed foods that have added sugar and that makes them different from things that are still delicious and savory, like you say, but perhaps in a very different way.

Nick Jikomes 44:55

Are there any measurable differences between cologne? Sweeteners and non caloric sweeteners in terms of how reinforcing they are. Well,

Nicole Avena 45:04

we have looked at this a bit, and again, it goes back to the sweet taste. And so to me, you know, because people will often say, Well, if I just use a non caloric sweetener, is that going to solve all my problems? And I'll say, well, it might save you some calories, but it's not going to solve your addiction to sugar, because it's the sweet taste that's driving the addiction, like response. So when we have these non caloric sweeteners, you know, the brain doesn't know that it's not a caloric sweetener. The brain, actually, I think, probably gets confused by the fact that, hey, I just had this sweetener, but I didn't get any calories. So what's going on here, right? So, if anything, I think, causes there to be some dysregulation in terms of the way in which our brain processes the signal of sweetness, in terms of the reaction that typically happens of it containing calories, and over time, what the research has shown is that, in fact, people who use those non caloric sweeteners, especially if they're obese or overweight, they're more likely to be consuming more food later on. So you might save yourself, you know, 100 or 200 calories by having a diet soda right now, but at the end of the day, you'll end up consuming more overall in terms of calorie intake. So I don't necessarily see them as beneficial for most people, especially for those who are trying to, you know, deal with an addiction to sugar, because it's still activating the dopamine system in the same way. Yeah,

Nick Jikomes 46:32

I could even imagine, you know, based on my knowledge of the reinforce reinforcement literature, you know, if you decouple, so if you've got, you've got, you've got a non caloric sweetener, you've got the sweetness, you've got that taste, but you don't have the calories behind it. You're creating sort of a mismatch. I could imagine the basically the dopamine reward circuitry tuning down its response such that when you do, if and when you do get a caloric sweetener in the future, now it's you know, that that signal is actually going to be boosted later? Yeah,

Nicole Avena 47:01

because the reward, in many way, for our body is the calories, right? We need the calories. And I think that is what exactly. What happens is that, you know, we're causing these issues to arise later on.

Nick Jikomes 47:18

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