Are We All Addicted to Ultra-Processed Foods?

DUBNER: I had a cow that once had chocolate milk. You’re saying that was an anomaly? 

*      *      *

DUCKWORTH: I’m Angela Duckworth.

DUBNER: I’m Stephen Dubner. 

DUCKWORTH + DUBNER: And you’re listening to No Stupid Questions. 

Today on the show: are ultra-processed foods addictive?

DUBNER: Oh man, the food industry is really running the show.

*      *      *

DUBNER: Angela, last week we talked about sloth, And we should say, the seven deadly sins are a sort of canonical list created within the architecture of the Catholic church. But we’re not talking about them really. We’re talking about the modern versions of them. So last week we started with sloth, which was, I thought, a crackling good time. I don’t know if you agree.

DUCKWORTH: I do.

DUBNER: And we may be picking the juicy ones to start with, but —

DUCKWORTH: They’re all juicy! Seven deadly sins!

DUBNER: Yeah, I guess they are. It’s a full juice bar. I don’t know. I feel like pride is less juicy than lust.

DUCKWORTH: Okay, we’ll see how exciting pride can be.

DUBNER: But today! We’re not doing pride, we’re not doing lust, we’ve already done sloth. Today we are doing gluttony. And I love gluttony.

DUCKWORTH: Are you gluttonous?

DUBNER: I hate to disappoint you here — I am less gluttonous than I was slothful. I did take your survey, which we’re going to talk about, but here’s a question I wanted to ask you about gluttony today. We did an episode sometime back in which we discussed whether your constant consumption of Diet Coke is actually an addiction. And we talked about what addiction is or is not, and it’s complicated! But, I recall you also once saying something — and I may be totally misremembering, so if I am, let me know — but I think you once said something like: “junk food is as addictive as cocaine.” If you actually said that or something like that, I want to know: what makes you say that? I want to know: how good is the evidence? And how we should all think about gluttony in the modern world.

DUCKWORTH: I want to walk it back, but not much. I can’t say that cocaine and Doritos are just about the same level of problem —.

DUBNER: They both do leave you with a powdery dust, though.

DUCKWORTH: There is that. I feel like I’ve figured out from reading the research on ultra-processed food in particular that it is addictive. I mean, I read this Annual Review — this is probably what was going through my head at the time — you know, Annual Reviews invite the world experts on timely topics to summarize everything that is known, past and present, on what the science says. And this Annual Review was called, “Is Food Addictive? A Review of the Science.” I think I stumbled upon it in part because you had asked me if I was addicted to Diet Coke. And I don’t Google things, I Google Scholar them. So, I read that Annual Review front to back, beginning to end, twice. And I found this argument that food can be addictive, in the same way that smoking or drinking or drugs can be, to be really compelling.

DUBNER: It’s not unintentional! In some countries and cultures, including the U.S., the share of calories consumed that are made up of ultra-processed foods is very high, I’ve read 60 percent. The fact is, the companies that make and distribute those foods are really, really, really good at providing us with incredibly delicious things I think that’s an incredibly worthwhile thing to discuss today because if you know even a tiny bit about the history of humankind and civilization and nutrition and food, we didn’t get here by eating xantham gum and sodium glutamate, all these things that make our foods bind and taste good and keep us coming back for more. So, whether we want to call it addictive or not, I think it’s a good way to get into gluttony. Because gluttony is something that you, as a researcher, feel was worth exploring in the modern world as a sort of opposite of self-control, correct?

DUCKWORTH: That is correct. And so let’s talk about food as one kind of gluttony that I think most people have some familiarity with firsthand. I mean, I don’t know many people who can say that they’ve never eaten to excess, you know, never, like, finished off a pint of ice cream or a bag of potato chips and then, almost at the moment that they’re doing it, regretting it. So I’m not just talking about people who have really chronic or severe issues with eating. All of us know what it’s like to live in modern times with foods that didn’t exist before. By extension, some of these other things that you could be gluttonous about — in terms of impulse shopping or drugs and alcohol — that’s also relevant. But the fact that it happens with breakfast, lunch, and dinner I think it says something about the way we’ve created our civilization. We have strayed from our evolutionary roots to create things that are so powerful that we can’t resist them.

DUBNER: The irony is that if you go back even just a hundred years, but especially 200, and very much 500 years, one of the biggest problems for humans on earth was not enough food. And now that problem visits many, many, many fewer people. In fact, we have quite the opposite problem.

DUCKWORTH: Let’s start with that because the kind of food that we overeat today was exactly the kind of food that would make us want to eat it. We’re hardwired to like sweet things. You don’t have to teach a baby to like sugar. All babies like sugar because sugar is high-calorie and when the world is starving — again, most of human history — more calories are better. Same for fat. So, when your doctor says, could you cut down on refined carbohydrates, don’t eat things that are deep fried, that would not be advice that your prehistoric ancestor — a paleolithic doctor — if there were such a thing — would say, eat as much fat as you can, get as many calories as you can get your hands on —.

DUBNER: Angie, sorry, can we pause for a minute? I just need to order some Popeyes right now so that it arrives during this conversation because your just talking about this literally had my mouth watering, no joke.

DUCKWORTH: Right!? These are reflexive urges. We have evolved to pursue carbohydrates — so sugar and also fat. A statistic from — well, I have two. One is about children from a paper called, “The Development of Sweet Taste: From Biology to Hedonics”. Here is the very first sentence of the abstract: “From the age of two years, an American child is more likely to consume a sugar-sweetened product than a fruit or vegetable on any given day.” I mean, wow.

DUBNER: I feel really lucky in this regard in that I grew up in a home where my mom was kind of an organic, back-to-nature freak before that was common. So I grew up believing that processed food period — forget about ultra-processed — was just not good for you. And I will say this: as a child, I hated it. I was the kid who would bring to school a sandwich of something on homemade wheat bread with sprouts. My dessert was an apple. And so, of course I wanted to have all the junk that some other kids had. And when I had a little bit of money and I could get to a store and buy some junk food, I certainly had the taste for that. But like you were saying, with the very young children, I don’t have a huge junk tooth or sweet tooth today and I think one big reason is because I grew up with a lot of natural food, much of which we grew or raised ourselves. So, I do feel fortunate in that regard. I think what this points to though is that a lot of people don’t even really know what processed food even is or means. And I think that’s intentional. I think the companies that make and sell and distribute food often like to present us with an image of food as being healthful, nutritional, even when it contains an awful lot of additives that are probably not so great. My favorite salad dressing in the world is ranch dressing, which may or may not be your favorite dressing. And the classic ranch dressing is called Hidden Valley Ranch that you can buy in a bottle.

DUCKWORTH: With the little green top.

DUBNER: Or you can buy the mix.

DUCKWORTH: That is kind of good.

DUBNER: It’s unbelievably delicious if you like that kind of thing. But I tend to make my own ranch dressing, which is mostly buttermilk and sour cream and mayonnaise, and then some seasonings. And it tastes pretty good. It does not have that certain je ne sais quoi of the Hidden Valley Ranch. And so I looked up the ingredients of Hidden Valley Ranch. And yes, it does include vegetable oil and buttermilk and sugar and salt, regular stuff, but also there’s your xantham gum, there’s your modified food starch, there’s your monosodium glutamate, there’s your disodium phosphate, there’s your calcium disodium E.D.T.A. And as it turns out, the more you dig into this topic of processed food and ultra-processed food, you find that many of these emulsifiers or coloring that are really just standard in a lot of American food are banned in other countries. So I think that from an American perspective, we are so deep into it that we often don’t even think about the fact that much of what we eat, whether it’s something as simple as a sauce or a salad dressing is just full of stuff that is ultra-processed. And then that leads us back to the question of not just nutrition but addiction. I’m reading here and I think this was where the phrase “ultra-processed food” originated. This is from a group of researchers at the University of Sao Paulo. They developed a classification system called NOVA. So group four, is ultra-processed. For the record, groups one is “unprocessed and minimally processed foods.”

DUCKWORTH: And the examples would be like eggs, like an apple.

DUBNER: As they call it, “the edible parts of plants or from animals.” And then we’ve got group two, which is “processed culinary ingredients,” which include things like oil, butter, lard, sugar, and salt. Number three would be “processed foods.” And, you know, let’s give processed foods their due. I think it was Napoleon who sponsored some competition to come up with a way to preserve foods so that he could get food to his soldiers on the front line. So, if we think about processed foods, these are canned or bottled vegetables, or legumes preserved in brine, whole fruit preserved in syrup, tinned fish preserved in oil, and some kinds of processed animal foods. They include ham, bacon, pastrami and smoked fish.

DUCKWORTH: It’s a deli.

DUBNER: A deli is the apotheosis of the processed food. So, let’s just call category three deli food. And then ultra-processed foods would become —

DUCKWORTH: That’s a 7-Eleven.  I think the food pyramid is out and this new taxonomy from “unprocessed” to “ultra-processed” is in. And the group four that we’ve been talking about are “industrial formulations made entirely or mostly from substances extracted from foods, derived from food constituents, or synthesized in laboratories from food substrates or other organic sources. Manufacturing techniques include extrusion, molding, and pre-processing by frying. Beverages may be ultra processed.”

DUBNER: Do you have a list of common foods that are ultra-processed products?

DUCKWORTH: Yeah. There aren’t names of brands, but I think we’ll all recognize the kinds of things that are on this list. “Fatty, sweet, savory, or salty packaged snacks; biscuits or cookies; ice creams; frozen desserts; chocolates, candies, and confectionary in general; cola, soda, and other carbonated soft drinks; energy drinks; sports drinks; canned, packaged, dehydrated, powdered, or other instant soups, noodles, sauces, desserts, drink mixes, and seasonings; sweetened and flavored yogurts, including fruit yogurts; chocolate milk; sweetened juices; margarine and other spreads; pre-prepared meat, fish, and pre-prepared pizza and pasta; pre-prepared burgers, hotdogs, and sausages.” So, I guess if you’re making your hotdogs from scratch at home, you’re good. The thing to know about these ultra-processed foods, it’s not — you know, you said, “xantham gum and all these additives” —

DUBNER: I think xantham gum on the spectrum is actually among the least bad.

DUCKWORTH: Exactly! So I was going to say, you know, some of these things have scary names and Stephen, I did not grow up the way you grew up. My dad worked for DuPont and as a chemist —

DUBNER: You put paint on your cereal?

DUCKWORTH: He was always defending the idea that just because something has a really long chemical name doesn’t necessarily mean it didn’t exist in nature or it’s bad for you. And he used to say in a scoffing way, like, “Oh, people care about their health and they think that things that have chemicals in them or are processed are bad.” But then he would just go on to, like, name the chemical formulas for things that happened in nature, or he would give me the formula for cyanide and he’s like, “Well that’s bad and that happens in nature.” But here’s the thing: we now know that this is bad, and I think more even than the additives and the flavonoids and the things that make things blue or rainbow is the combination of fat and sugar. In the Annual Review, the authors take this from a neuroscience angle. So according to their perspective, it’s this magical, devious, really, combination of eating something which is really sweet, but at the same time fatty. And they point out that mother nature does not make any food that is sweet and fatty at the same time.

DUBNER: What about chocolate milk? I had a cow that once had chocolate milk. You’re saying that was an anomaly?  Now that I think about it, I think that cow was given to us by the Hershey Company, so maybe that was some kind of product placement.

DUCKWORTH: Yeah, I would have my suspicions about that. But this category four is bad mostly because of that because the built-in instinct that we have for sugar just goes crazy when there’s also fat. Have you ever heard of a supernormal stimulus?

DUBNER: I have not.

DUCKWORTH: If you look at classic ethology research — this is the study of animal behavior — and you go all the way back to Konrad Lorenz and Niko Tinbergen, the sort of O.G. animal ethologists who built the field, one of their early observations was that if a bird knows to roost in a certain nest and take care of its own eggs because of their shape and color, if they are tricked in a way by another bird’s eggs, even a different species, that have the same shape and coloring, but it’s kind of exaggerated — it’s blue, but it’s really blue, it’s speckly, but it’s really speckled, like the contrast is really high — then the bird can get tricked and start roosting in an nest that’s not its own and neglect its own eggs. I think this was Lorenz who made this observation because he was looking at these baby chicks and their behavior, which was genetic, it was like built-in. When they were feeding, they would recognize the mother by the contrasting mark on the mother’s bill. And what Tinbergen did was he created an artificial — he had like a stick and he painted it red, it had like a dot on it, but he just made it bigger. And then he could elicit from these baby chicks an exaggerated response and they would ignore their own mother. So I think the basic idea of a supernormal stimulus is something that was invented by human beings that is an exaggeration of something that happens in Mother Nature and it evokes an exaggerated response.

DUBNER: Here’s something I find really interesting as a description of what ultra-processed foods really are if you think about them from a production standpoint: “ultra-processed foods use low-cost ingredients to create highly-profitable products with a long shelf life. Their convenience, hyper-palatability, and ownership by large, transnational corporations give these foods huge marketing advantages.” So again, these are foods that are not only ultra-processed, not only extremely palatable, meaning delicious, but they’ll stay on the shelf forever. And, one common theme, at least in the cereal category, is that they include an awful lot of sugar. So even if you were worried about sounding like a crazy, tinfoil-hat wearing conspiracy theorist by saying that, “The food industry is really running the show” — mmm, you probably should forgive yourself. There’s a history of soda companies funding research years and years ago that showed that sugar wasn’t so bad. There’s obviously research going back funded by cigarette companies showing that cigarettes are not so bad. So there’s good reason to be a wee bit suspicious of the ultra-processed food revolution and to talk about ways to dial that back.

DUCKWORTH: The conclusion of this Annual Review article that I love so much has a couple sentences I think are worth reading. “Ultra-processed foods now dominate our food environment and are created in ways that parallel the development of addictive drugs, including the inclusion of an unnaturally high dose of rewarding ingredients that are rapidly absorbed into the system and enhanced through additives. As with addictive drugs, some, but not all, individuals exhibit an addictive pattern of consumption marked by diminished control over intake, intense cravings, and an inability to cut down despite negative consequences.” And they have a scale, by the way, it’s the Yale Food Addiction Scale, and it’s got items like, “I ate to the point where I felt physically ill, my eating behavior caused me a lot of distress, I tried and failed to cut down or stop eating certain foods, my friends or family were worried about how much I overate.” You know, one of the things that I learned by reading through this research is that it’s not just that we have a craving for sugar that’s accentuated by the presence of fat. It’s not just that. There’s a feature of these ultra-processed foods that are like pulverized and extruded and then fed to us. They are practically pre-chewed, so they literally melt in the mouth. I know I made that maybe flippant comment saying that junk food could be like cocaine, but one of the features of the drugs that create addiction is that they’re extremely rapidly processed by the body. Let’s take nicotine, for example. When you smoke a cigarette, you get a very, very fast nicotine high. You know, the smoke goes into the lungs and nicotine passes through to the blood. If you wear a nicotine patch, by design, the nicotine is released very slowly. And one of the articles that I read was about how when you look at the pharmacokinetics, so the absorption over the course of milliseconds, and you do look at something like cocaine and, say, sugar, for example, it has a very similar, fast profile. And so, oh my gosh, these things are so cheap, so available. They come in combinations of fat and sugar that never existed. They come pre-chewed for you. It’s hard to not feel pretty reactionary? I don’t know — indignant? Horrified? I don’t know. It’s bad.

Still to come on No Stupid Questions, Angela gives advice on how to fight the temptation of ultra-processed food.

DUCKWORTH: Because you can’t move to another planet.

DUBNER: I think all the billionaires are doing that, but you and I aren’t going to move to another planet.

*      *      *

Now, back to Stephen and Angela’s conversation about gluttony.

DUBNER: A few years ago we did an episode of Freakonomics Radio that was very similar, in some ways, to this conversation we’re having. The episode was called, “There’s a War on Sugar. Is it Justified?” And the questions we were exploring were: How harmful is sugar in large and regular doses? Assuming that the answer is that sugar is harmful in large doses,  whether sugar should be regulated more carefully, because right now it’s really not. And also we explored the degree to which sugar is, in fact, addictive. One of the most prominent sugar voices in the world that we spoke with is Robert Lustig, who’s a pediatrician with the Institute for Health Policy Studies at U.C. San Francisco. He’s president of something called the Institute for Responsible Nutrition. He makes very, very, very strong, and I find fairly compelling arguments about the damage that sugar has done to us societally. Some people consider him a little bit too —.

DUCKWORTH: Too radical?

DUBNER: Too radical, too anti-sugar. But, we spoke with a number of people. Another was a research neuroscientist at Mount Sinai. Her name is Nicole Avena. She studies addiction and one question she posed, she said: “can sugar, when it’s consumed in excess, produce some of the behavioral indications and neurochemical indications that you would typically see with a substance of abuse?” And when I asked her to think about the current appetite among some people, including Lustig, for a much heavier hand when it comes to the regulation of sugar, and whether the emerging model of sugar “addiction” lines up to the addictive criteria for the sorts of drugs that we do regulate — here, I’ll read a little quote from her. She said, “It’s a difficult question because sugar is safe when it’s used in moderation, but the problem is that most people are unaware of how much sugar they’re consuming. Also, if the data suggests that the sugar is producing addictive-like changes in the brain, then we are talking about something very different. Because if you are no longer able to have full volitional control over your decision to eat or not eat the sugar, then that becomes a different type of discussion.”

DUCKWORTH: But that’s the very problem, I think, maybe not only with this sin, but with others. I don’t know of anything, when it comes to human behavior, that’s really just a categorical distinction. Like, “either it’s really impossible to resist or it’s not at all.” It’s on a continuum. And I think the argument that these ultra-processed foods are farther than you would think on the continuum of the way that they interact with the brain’s dopamine system, with our opioid reward system, the pharmacokinetics, the rate of absorption. And then also things that are just about economics, right? Their wide availability, the unbridled marketing, the fact that we give these things to kids. I mean, I won’t be able to sleep tonight with the knowledge that kids are more likely to have an ultra-processed food as a part of their daily diet than a fruit or a vegetable on any given day?

DUBNER: And by the way, apple juice and orange juice are processed foods, probably ultra-processed foods. We’ve been persuaded societally like, “Oh, apple juice, fantastic. Orange juice, great.” But the amount of sugar in there is absurd. The problem, I think that you’ve just identified really beautifully, is that we are just swimming in this water without thinking that it’s water. I am encouraged by a statistic I found. I’ll put it in quiz form for you: If you look at the different generations that are typically called boomers, then Gen X, then millennials, and then Gen Z, the youngest — which of those generations would you say ranks highest on the avoidance of consuming sugar in the U.S.?

DUCKWORTH: I think the Gen Z-ers probably.

DUBNER: You are right. According to this Statista compilation of data, Gen Z shows 29 percent survey respondents avoid sugar. Who knows what that means by avoid sugar, and again, it’s a survey. Millennials and Gen X are about the same, 14 and 16 percent respectively. Boomers are the lowest, which really surprised me. Boomers are only 10 percent. And what that may be indicating is that boomers were born in an era where ultra-processed foods were considered a great gift.

DUCKWORTH: “Science has given us better food,” I think, was the general received wisdom at the time.

DUBNER: It’s delicious, it’s portable, it’s extremely palatable, it’s very affordable, and it was considered a great benefit. And it may be that when you’re conditioned to embrace that, you are going to keep eating the same thing. And that more and more younger people are becoming a little bit hip to the idea that a lot of foods that we pursue — even those that are presented to us as a healthy option or an organic option — are just as garbagey as the rest. And so that people are getting a little bit savvier about looking at labels to see what kind of sugar content, what kind of ultra-processed ingredients are included therein. So, that’s a little bit encouraging, at least.

DUCKWORTH: Yeah, I think I should actually give some advice here. Because you can’t move to another planet.

DUBNER: I think all the billionaires are doing that, but you and I aren’t going to move to another planet.

DUCKWORTH: Well, for the rest of us. You know, you can’t really take ultra-processed food out of culture, but I do have a couple of pieces of advice. So, one mental trick that you could do is, the next time you pass a billboard for Popeye’s or like, “ooh, free chips on the airplane,” just stare at that thing and ask like, how far from category one in the NOVA classification is this? Will it melt in my mouth? Like, gee, I wonder what it’s going to do to my dopamine system. Reframing it is a cognitive trick. And I also want to say, I think the cleverest thing you can do is to change your micro-situation. So no, you can’t change the way food is manufactured in the United States, you can’t change the layout of your local supermarket, but you have some autonomy over the way you stock your own refrigerator. You do have a choice of where to go out to eat, if you’re going to go out to eat and so forth. So, I think situational strategies are even better than these mental tricks because they kind of offload the burden of self-control onto a situation — which, again, you don’t have full control over, but at least in your immediate habitat, you have some control over.

DUBNER: I’d love to hear from listeners how they have successfully or unsuccessfully avoided what they consider the temptation of gluttonous pursuits. Probably it’s food or alcohol or drugs, but maybe it’s something else. Maybe it is drunk shopping or whatnot. So if you have an example of your avoidance or falling prey to gluttonous consumption, send us a voice memo and maybe we will play it on a future show. Just record using your smartphone. Go to a quiet place. Include your name and what you do, and send it to us at nsq@freakonomics.com. We should also say, Angela, you have developed a seven deadly sins survey that you were offering to our listenership, correct?

DUCKWORTH: That is correct, Stephen. And there is a gluttony scale on it. So, if you fill out the survey, you will get your gluttony score — not just for food, which we’ve been discussing, but also for drugs and alcohol and for impulse shopping.

DUBNER: And you can find that survey in the show notes of this episode on your podcast app. It’s also listed on the No Stupid Questions website, the landing page. The actual survey is hosted on a University of Pennsylvania site. And we should also say: you are collecting this survey data from listeners just for fun, not for research.

DUCKWORTH: Yeah, I’m hosting it on a Penn server for reasons of it being a very secure way to do it. But it’s anonymous, first of all, and second of all, I’m not using it for research.

DUBNER: I want to say one last thing. When we’re talking about gluttony the deadly sin, early Christian theologians understood gluttony to be drinking too much alcohol, eating too much food — especially fine food, like a desire for food that was fancier than one needed to sustain oneself. But interestingly, when they talked about the opposite of gluttony, it wasn’t moderation; it was abstinence.

DUCKWORTH: From food? Wait, how long can you do that?

DUBNER: Well, when you look at the list of the seven deadly sins and the corresponding heavenly virtues, the ones that sort of address or cancel out those sins, the virtue that works against gluttony is abstinence. Maybe that word meant something slightly different then, but I should say I don’t think that’s a very useful word to think about now because, we need to eat and we love to eat. So it’s not a question of going from a hundred to zero. It’s a question of self-control, really, which is what your whole argument is about. If there are areas in our lives where we exercise a high level of self-control and others where we have a low level, do you believe that one can learn from the areas of high self-control and port them over into the low?

DUCKWORTH: I do believe that to some extent we can learn from a domain where we’re really good at resisting temptation and then port it over, but by and large, the idea is to understand what your triggers are and to avoid them in the first place. And I think the best people to listen to are the authors of that Annual Review. They write a whole paragraph about how, in some ways, this addiction that they consider to be real about ultra-processed food is the analog to being addicted to alcohol. And so they say, look, let’s learn from what has and hasn’t worked for alcoholics. Because likewise, it’s very, very hard to find a place to live in the world that has zero alcohol, right? That has like nothing that’s going to tempt you. So what they advocate is finding the situations that are going to trigger binge eating of ultra-processed foods or uncontrolled eating. And here’s the very ending of the paragraph: “Thus, treatment would emphasize abstaining from high-risk situations, while permitting appropriate engagement with the addictive substance in low-risk contexts.” So you can just think to yourself, where are times where, you know, I eat some Doritos, drink some soda, it’s okay — and where are times when I really regret it? And then avoid those high-risk situations.

DUBNER: I have to say, I am a glutton for Duckworth. I can’t get enough of these conversations. Angie, as always, thanks and I’ll talk to you soon.

DUCKWORTH: Well, there’s more where that came from. Looking forward to it, Stephen.

This episode of No Stupid Questions was produced by me, Katherine Moncure, with our production associate, Lyric Bowditch. And now, here’s a fact-check of today’s conversation.

Early in the conversation, Stephen refers to an ingredient in many ultra-processed foods as xantham gum, and then Angela also calls it xantham gum later on. The additive is actually called xanthan gum, with an N. Stephen also says “if you know even a tiny bit about the history of humankind and civilization and nutrition and food, we didn’t get here by eating xantham gum and sodium glutamate.” In fact, xanthan gum and sodium glutamate, more commonly known as monosodium glutamate, or MSG, both occur in foods found in nature. Though not always in the quantities in which they’re found in modern processed foods.

Then, Angela refers to flavonoids as one of the unnatural components of ultra-processed foods. In fact, flavonoids are both naturally occurring and good for you. Flavonoids are in many fruits and vegetables and they help fight viruses, inflammation, and cancer.

Later, Angela says that Konrad Lorenz and Niko Tinbergen were the original animal ethologists. But, Tinbergen credited the first observation of supernormal stimuli to ethologists Otto Koehler and Arno Zagarus in 1937.

Then, Stephen refers to pediatrician Robert Lustig and his role as the president of the Institute for Responsible Nutrition. In 2017, the Institute for Responsible Nutrition merged with another organization and was rebranded as Eat Real, where Lustig is now Chief Science Officer.

And, finally, Stephen describes apple juice and orange juice as processed or ultra-processed foods. That’s true of apple and orange juice drinks that have sugar added. But pure apple and orange juice, whether pasteurized or not, are in NOVA group one: unprocessed or minimally processed foods.

That’s it for the fact-check.

Before we wrap today’s show, let’s hear some of your thoughts about last week’s episode on sloth:

Annie HILL: Hi, this is Annie Hill from Denver. So in terms of my running, I used to wear a pace watch. I used to run to try to make sure I was running under nine-minute miles, and I was getting better and better. But the more I trained, the more my body hurt, and when Covid hit and I couldn’t sign up for any more marathons, I slowed my pace way down and I realized, gosh, my neighborhood is more pretty. There’s a hawk in that tree or a bald eagle, and my body stopped hurting. And so now running is so much more enjoyable, and I feel more healthy. And I’m less judgy. I don’t see somebody and say, oh, “Look how slow that person’s going.” They’re out there enjoying nature and yeah, I’m a better person for it.

Sabrina COLOSIMO: I’m Sabrina Colosimo. I’m from Toronto, Canada, and when I hear people like Angela say how they’re basically never like a sloth and they’re always achieving, it feels so foreign to me. I’m a creative and even when I have the best of intentions to lay out a plan, I find it very hard to stay on course and get things done. A lot of that time is spent just ruminating, procrastinating, and I think a lot of creatives would agree with this, that sometimes the rumination and the procrastination is actually, a valuable part of the process.

ANONYMOUS:  I am a veterinarian. In our profession, we are caregivers by nature. You have to be a high achiever to get into veterinary school. The education itself is grueling. And then once we get out, we are under enormous pressure to produce revenue for our employers to practice high quality medicine, and above all, to see all the patients. And there are always more patients to be seen than we can fit in the hours available in a day. If you look at the statistics for our profession for burnout and mental health struggles and the suicide rate, it is alarming. In that context, Embracing being a sloth from time to time or on a regular basis is definitely a virtue. I think of it as putting healthy boundaries between work and some time to rest and recharge. Not to be overly dramatic, but in that situation it really is a matter of survival.

That was, respectively: Annie Hill, Sabrina Colosimo, and a listener who asked that we not use her name. Thanks so much to them and to everyone who sent us their thoughts. And remember, we’d still love to hear how you navigate your own temptations with gluttony. Send a voice memo to NSQ@Freakonomics.com. Let us know your name and whether you’d like to remain anonymous. You might hear your voice on the show!

Coming up next week on No Stupid Questions: Stephen and Angela discuss why many people these days… just aren’t having that much sex.

DUBNER: So much to discuss and unpack here.

DUCKWORTH: So much to undress here, so to speak.

That’s next week on No Stupid Questions.

*      *      *

No Stupid Questions is part of the Freakonomics Radio Network, which also includes Freakonomics Radio, People I (Mostly) Admire, and Freakonomics, M.D. All our shows are produced by Stitcher and Renbud Radio. This episode was mixed by Eleanor Osborne, with help from Jeremy Johnston. We had research help from Rebecca Lee Douglas and Dan Moritz-Rabson. Our executive team is Neal Carruth, Gabriel Roth, and Stephen Dubner. Our theme song is “And She Was” by Talking Heads — special thanks to David Byrne and Warner Chappell Music. If you’d like to listen to the show ad-free, subscribe to Stitcher Premium. You can follow us on Twitter @NSQ_Show and on Facebook @NSQShow. If you have a question for a future episode, please email it to nsq@freakonomics.com. To learn more, or to read episode transcripts, visit Freakonomics.com/NSQ. Thanks for listening!

DUCKWORTH: Juice, juice, juice!