Humans eat just like every other living creature. Have you ever wondered what drives us to binge eat, or spend too much time at the grocery store? And how does the food we eat impact us emotionally? We talk to Dr. Rachel Herz, author of "Why You Eat What You Eat: The Science Behind Our Relationship with Food," about the surprising science of food in our daily lives. Dr. Herz is a leading world expert on the psychological science of smell, and has been conducting research on olfaction, sensory perception, emotion, motivated behavior and cognition since 1990. She holds an adjunct appointment in the Department of Psychiatry and Human Behavior and sometimes teaches in the Department of Cognitive, Linguistic and Psychological Sciences at Brown University. Additional resources discussed: "Why You Eat What You Eat: The Science Behind Our Relationship with Food" Dr. Rachel Herz website (RachelHerz.com) Dr. Rachel Herz faculty bio (Brown University) Diet beverage drinkers compensate by eating unhealthy food, study finds (Science Daily) U.S. News Best Diets: How We Rated 40 Eating Plans (U.S. News & World Report) Think organic food is better for you, animals, and the planet? Think again (The Telegraph) Does organic farming reduce environmental impacts? – A meta-analysis of European research (ScienceDirect) Are Organic Foods Safer or Healthier Than Conventional Alternatives?: A Systematic Review (American College of Physicians) Conventional and organic foods: A comparison focused on animal products (Cogent) Grapefruit And Salt: The Science Behind This Unlikely Power Couple (NPR) Follow Curiosity Daily on your favorite podcast app to get smarter withCody Gough andAshley Hamer — for free! Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
Humans eat just like every other living creature. Have you ever wondered what drives us to binge eat, or spend too much time at the grocery store? And how does the food we eat impact us emotionally? We talk to Dr. Rachel Herz, author of "Why You Eat What You Eat: The Science Behind Our Relationship with Food," about the surprising science of food in our daily lives.
Dr. Herz is a leading world expert on the psychological science of smell, and has been conducting research on olfaction, sensory perception, emotion, motivated behavior and cognition since 1990. She holds an adjunct appointment in the Department of Psychiatry and Human Behavior and sometimes teaches in the Department of Cognitive, Linguistic and Psychological Sciences at Brown University.
Additional resources discussed:
Follow Curiosity Daily on your favorite podcast app to get smarter with Cody Gough and Ashley Hamer — for free! Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
Full episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/why-we-eat-what-we-eat
CODY GOUGH: I'm curious. Why don't we all just eat healthy?
RACHEL HERZ: Well, because we're actually programmed to love salt, sugar, and fat because we evolved in a landscape where a good calorie was hard to find.
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CODY GOUGH: Hi, I'm Cody Gough with the delicious and nutritious curiosity.com.
ASHLEY HAMER: I'm Ashley Hamer. And today, we ask the question, why do we eat what we eat?
CODY GOUGH: Every day, we explore what we don't know because curiosity makes you smarter.
ASHLEY HAMER: This is the Curiosity Podcast.
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CODY GOUGH: We all eat. And by "we" I mean literally every living being on the planet. But why do we eat what we eat?
ASHLEY HAMER: Also, why do we have cravings? What's really going on in the grocery store, and why do we eat ourselves sick when we know we're full?
CODY GOUGH: Today, we'll get some answers from the author of the book Why You Eat What You Eat, the science behind our relationship with food. She seems pretty appropriate for this topic
ASHLEY HAMER: Dr. Rachel Herz is a professor in the Department of Psychiatry and Human Behavior at Brown University. And she's a leading expert on the psychological science of smell. She's been conducting research on olfaction, sensory, perception, emotion, motivated behavior, and cognition since 1990, so kind of a big deal.
CODY GOUGH: This is a field that encompasses a lot of different disciplines, right? A little bit of neurology, a little bit of psychology, a little bit of physiology.
RACHEL HERZ: Absolutely. This is really a book about everything to do with the environment both right up front in your face-- what you see, what you smell, what you feel, what you hear, as well as the environment that goes on around you. So the context you're in, the social environment you're in, and the environment in your brain, the mood you're in, your personality, and so forth. There is all those factors that go in together to create the dance we have with food and eating.
CODY GOUGH: Yeah. And it's quite the elaborate dance really. There's a lot of different stories in there, about people's particular experiences, and, of course, studies. It answers the question how and why our senses and, like you said, mind and environment are impacted.
But I want to start with a couple of broad practical things people can do right now to improve their food experience. So if I'm about to go grocery shopping and you're looking at the research you put into this book, you go to the grocery store. What are you thinking about that the average person isn't thinking about, and how can I take care of my brain's impulses and urges but also take care of my body at the same time?
RACHEL HERZ: So there's two really fascinating studies about grocery store shopping that I talk about in the book that, I think, are-- they were actually a surprise to me. And, I think, that everyone who is a consumer should be aware of them.
One of them is the fact that if you bring your own reusable bag to the grocery store and you're not shopping someplace which penalizes you if you don't bring it, that if they make you pay for a thin film plastic or they won't bag you at all or whatever the case might be, but if you're doing it out of the goodness of your heart and you're helping mother nature and you're feeling environmentally conscientious about things, then two things happen.
One isn't very surprising, and that's that you tend to buy more organic produce and products than otherwise if you didn't bring your own bag. But the other which is surprising is that you buy yourself more treats, so those little impulse delicious snacks that you may not have purchased. Otherwise, you're more likely to give yourself. And this is because we like to balance our virtues with vises.
So in this case, the virtue is bringing your own bag. And the little vise is I'm going to give myself a little package of donuts or chocolate covered cherries or a bag of French fries I'm going to make later or whatever the case might be. And this is because we're giving ourselves a little reward, a pat on the back for doing this. And now, the problem, however, is that all these rewards can add up to calories that you might not have wanted to consume.
Another thing that's really fascinating about being in the grocery store is that it was found-- this was a big study done-- but they had radio frequency tags on people's shopping carts so they could tell where in the geography of the store people were going. And it turned out that after people had been in the produce aisle and they were putting grapefruit and kale into their carts, the next place they went was either the ice cream or the alcohol sections of the store.
CODY GOUGH: Oh, no.
RACHEL HERZ: So again, this balancing virtue with vise. So we tend to say, oh, we just did something really good for our health. Now, we're going to do something which is maybe more questionable.
ASHLEY HAMER: Your tendency to reward yourself for making healthy choices is one reason some scientists say diet soda might not be great for your waistline. In 2015, a huge study looked at 10 years of dietary habits of more than 22,000 people to see what kind of drinks and junk food they consumed every day.
The study showed that even though people who drank a lot of alcohol or sugary beverages consumed the most calories overall, people who drank diet soda got a greater percentage of their daily calories from junk food. Researchers aren't sure why this is, but it could be that when you drink diet soda, you reward yourself for your good behavior by reaching for a cookie or a bag of chips.
RACHEL HERZ: And so these are things that, I think, it's just good to be aware of because the whole idea is that if you have the knowledge of what is going on around you and all the little subtle impulses and influences that are directing your experience with food and eating, then you're capable of taking the power back and having control over what you're going to do, what you're going to eat and so on rather than feeling the food environment is controlling you.
CODY GOUGH: Do you think that that's the primary way to combat this, is just the sheer awareness of it? If I bring in my own bag to the store and just the fact that I know that I might buy more chocolate is going to help me not buy as much chocolate?
RACHEL HERZ: Well, there may be other ways. But I certainly think that the knowledge is the number one upfront reason to be aware of. And if you have that information then-- hopefully if you just remind yourself that, even if you forget it while you're in the store-- but just a quick reminder can make you a little bit more assiduous while you're going through the aisles and so forth in what you're doing.
And if you do reach for that extra box of chocolates, you might be re reminded again that, hey, wait a second. Is this something that I'm just giving myself because I brought my bag or because I'm feeling sort of good about wanting to reward myself, or do I really, really want these chocolates? Of course, if you really, really want the chocolates, go for it. But it's kind of like this sort of, why are you doing what you're doing? And I do think knowledge has a huge influence on what we do.
CODY GOUGH: Yeah, you mentioned if you want the chocolate, then go for it. I have to ask. Is the phrase "everything in moderation" true?
RACHEL HERZ: I think so. I mean for me, sort of a mantra to take out of the book is variation and moderation. One thing with respect to variation is that a very diet is much healthier than a diet that focuses on a small select group of foods just as a general fact. And moderation is also the key. So eat everything and anything so as widely varied as possible but just not too much of any one particular thing both from the point of view of health.
Because even if you were focusing on just, let's say, eating certain vegetables, which are ostensibly healthy, if that was all were eating, you'd be missing out a lot of really important macronutrients. Obviously, we can all say that's logically not very healthy. But, I mean, the same goes for a diet of chicken wings and chocolate bars. So we have to realize that although these are things that might be really tasty and they provide certain macronutrients, protein, carbohydrates, and so forth, we don't want to just limit those sources to a very restricted set of foods. You want to be able to diverge into other kinds of foods as well.
CODY GOUGH: Oh-oh. I might be in trouble. Every morning, I eat 3 to 4 hard boiled eggs for breakfast and one or two cups of coffee. I figure protein that's a good way to start the day. But you're saying that it might be better even, though, those are really healthy in general to maybe one or two days a week have a bowl of cereal or a bowl of oatmeal?
RACHEL HERZ: Well, certainly. But the other thing is I'm saying from the point of view of your full day. So if all you were eating was hard boiled eggs, that would be much more of a problem than if-- people often like to have certain rituals for particular meals. I'd say breakfast is probably the number one where people generally speaking are more likely to have the same thing day in day out. And that's OK as long as for lunch and dinner you're mixing it up and not having only the same thing all the time.
So I'm not saying that it's a bad idea to have certain things that you eat all the time. But in addition to that, you should be bringing in a lot of different foods so that you can maximize the sources of nutrients that you're getting.
ASHLEY HAMER: That's one reason why a lot of weight loss diets aren't actually all that good for you in the long run. Every year, US News and World Report puts together a panel of diet and nutrition experts to rate dozens of popular diets on a bunch of different elements from how effective they are to how nutritious they are to how easy they are to follow.
In their 2018 list, almost none of the diets that ranked the best for fast weight loss made it on the list of the healthiest diets mostly because many require you to drink meal replacement shakes or cut out entire food groups like carbs or dairy. There were two diets that landed on both lists for their ability to help you lose weight and stay healthy, however. One is the Volumetrics Diet, which has eat a lot of high volume, low calorie foods, like fruits and veggies so you feel full faster.
The other, which ranked at the top of the best weight loss diets and at number five for health, was Weight Watchers. Weight Watchers assigns different foods smart points and gives you a certain number of points per day. Importantly, it also uses in-person meetings and other social support to help you stay the course. The moral of the story, if you're looking to lose weight, you can do it without sacrificing your health.
CODY GOUGH: We've talked a little bit about the internal motivators of why we might buy certain things and some of our behaviors. But there's also just to get back to the grocery store, you also write about marketing in your book and the impact that companies and brands have on our buying decisions. How are corporations impacting our behavior in good or bad ways that we need to be aware of?
RACHEL HERZ: Well, I would say, unfortunately, they're mainly impacting it in bad ways from the point of view of they want us to buy their products. So if the product isn't super healthy, then that could be a bad thing for us. There's a couple of little interesting things to be aware of.
One is that just the package itself, what it looks like. And it turns out that if there are more pictures of the thing that you're going to be eating on the package, the more likely you are to want to buy that package. So let's just say there are two brands of potato chips. One has a bunch of potato chips on the cover of the box, and the other has like one or two.
You're more likely to go for the one that has a bunch of potato chips because we like seeing more. And more is more appealing to us when it comes to food. And therefore, we're more likely to, let say, pick the brand that has more visual iterations of what's inside. And this is especially the case when we're going to be eating more of the things. So it's not like you just have one potato chip and then stop.
Another thing that's really important to be aware of I would say more important is the labeling itself, the words that go into describing the product. And here, it's a little bit of a surprise maybe to some people that when we see the word organic or all kinds of words connecting to health, we actually often ourselves make miscalculations about what is in the product and whether or not it's actually really healthy for us and how many calories it contains.
And people actually think that organic cookies contain fewer calories than conventional cookies, that they are somehow healthier for you, that they're actually promoting your health when you consume them. So much so that people will even sometimes say that it's OK to forgo working out after eating an organic cookie versus not even eating a cookie at all, which to me is sort of incredibly illogical. But from the point of view of how we presume, organic means health promoting. It's we can see how people would then say, well, I don't need to do something else that's health promoting because I've already done one thing.
And, although, certainly from the point of view of the environment and there's all sorts of reasons why organic is good. But when it comes to things like cookies and treats, it is really important to be aware to not get duped into thinking that they are actually in fact healthy and that we can forgo other sorts of healthy things and also that we can eat more of them because that's not the case either.
CODY GOUGH: Yeah, we actually have a skeptic in our office at curiosity.com who is not really sold on the whole, if it says organic, it's immediately better and immediately healthy for you.
ASHLEY HAMER: Hello, I'm that skeptic, and here's why. Dr. Herz mentioned that organic is better for the environment, which is a common idea. It's true that organic farms promote more biodiversity than their conventional counterparts, which is good for the environment.
But what you might not know is that organic food actually has a larger carbon footprint than conventional food because growing it isn't as efficient. It takes 84% more land to yield the same amount. Likewise, a lot of people think that organic means it's pesticide free. Again, not the case.
Organic farmers aren't allowed to use synthetic pesticides, but they can use so-called natural pesticides, like copper sulfate, which is still pretty toxic. And research shows that organic food isn't any safer to eat than conventional. OK, but it's better for you, right? Nope.
Multiple reviews of the research has found that organic products are no more nutritious than conventional food. According to the science, you're paying extra for that organic broccoli for absolutely no reason. Check the show notes for some links if you want to read more.
CODY GOUGH: How do you even know what's healthy? And are we all inclined to eat healthy? I mean, why don't we all just eat healthy?
RACHEL HERZ: Well, because we're actually programmed to love salt, sugar, and fat because we did not evolve in the landscape of a supermarket and a Starbucks on every corner. We evolved in a landscape where a good calorie was hard to find. And so we are programmed to love the taste of things which signal high carbohydrates, high calorie, and the macronutrients we need-- so proteins, fats, carbs, salt and so forth.
We actually need all of that in order to sustain our bodily functions to live healthily and so forth. And so going back to that for a second. So when we taste those things, the taste of sugar is really fantastic. The feel of fat in our mouth is innately really pleasurable.
Salt is also interesting. Salt is pleasurable. And the more salt you consume, actually the more salt you like and the more salt you want. So this is something that's experience dependent but builds on itself like a bit of a wheel. So all these things that's really great in the short term.
Salt is a signal for protein. Sugar is a signal for carbohydrate. We need fats for all kinds of reasons. Fats are really important. But again, when there is this super abundance and our brains are going fabulous, we need to rein ourselves in for a second, go, hold on. This may be what we're programmed to do. But let me take a little step back and be a bit more commonsensical.
And this is, I guess, where I come from with a lot of the perspective as well. So variation, moderation, and common sense. So one of the things that I have a little problem with is every day if you were to look at nutritional and medical advice, it's changing almost on a daily basis.
And, I think, that you need to take this advice with a certain grain of salt. And also just use common sense. I mean, this is where moderation comes into play. And the salt example is really one that speaks to this because what the American Heart Association says is the amount of salt people should be consuming.
When this was another really large study that was done looking at people who consumed that amount or less, people who consumed more than that amount, and then people who were consuming like way more than that amount. And the people who consumed the least amount in the zone that the American Heart Association said was the best were actually less healthy than people who were in the middle zone and also obviously people who were in the top end. So it's kind of like the Goldilocks thing where the middle is probably the best way to go and just use common sense when you're thinking about what to buy and how much to eat and what to eat.
CODY GOUGH: I'm a little bit thinking about which came first, the chicken or the egg here, because you talked about how we kind of all want fat. What I found really interesting in the book when you talk about fat is that our emotions and our mood can have a huge impact on the way we're perceiving the fat and how much fat we're maybe craving or wanting. So how is our mood impacting what we're eating, and how do we balance that then with just what we generally want on kind of your average, run of the mill afternoon?
RACHEL HERZ: So I'm glad you asked that question. That's actually a great point. So one of the things that's interesting too-- and here I guess also where the information in the book can just inform you well you're going, oh, wait a second. I'm not really getting. This doesn't taste the way-- as sweet as I wanted to. I'm just going to eat another and another and another.
Maybe think back and say, well, I'm actually in this really crummy mood, and I'm really stressed out and that's maybe why. Because it turns out that when we are really stressed, sweet, or unhappy, sweet does not taste as sweet.
In order to sort of, let's say, get to the sweet bliss point they're searching for, we'll eat more and more to get to the point where they go, OK, now I'm satiated. I've gotten my sweet where as if they were in a good mood. That sweetness would have more of an impact and would taste sweeter at the time.
And likewise with fat, the same kind of thing happens, although, a little bit differently. People when they're in a bad mood or a sad mood aren't really able to differentiate between how much fat is in something, let's say, that's full, full triple cream versus skim. And that's an interesting thing as well because the idea here is twofold.
One, if you can't really tell the difference, then why not go for the lower end? Because you're going to be just as satisfied. And the other thing is that be careful.
If you're using a lot of cream, let's say, and you realize that you're in a bad mood or a sad mood because that may be another reason why you're potentially using more or you're not even really appreciating the positive from it-- so again, just being aware of these things that when we're in bad or sad moods, the high points of food are not as high, and we tend to overuse them or be kind of indiscriminate about what we're perceiving.
CODY GOUGH: And we won't get too into the nitty gritty of all the science of this, but this is because smell and taste are pretty much directly wired into our brains, right?
RACHEL HERZ: Well, all of our senses are directly wired into our brains, but--
CODY GOUGH: Sure.
RACHEL HERZ: --that would be a problem.
[LAUGHTER]
But the sense of smell in particular is wired into the emotion centers of the brain. And that is one of the reasons why a sort of on a different tack, smells can make us feel really comforted. One of the reasons aromas of comfort food can be so rewarding is because of that.
But from the point of view of these sort of the bliss points of sweet and fat and so forth, that has more to do with the neurotransmitters of reward and the areas of the brain that are activated when our brains are being happy because we're eating something. So the reward centers in the brain that are activated by eating and tasting something sweet or tasting something that's creamy are less engaged. They're sort of less active when we're upset. And therefore, they need more stimulation, AKA more sweet and fat in order to get to the same level. So that's more the reason why there.
CODY GOUGH: There are particular health benefits or, I guess, our body reacts in certain ways to each of the fab four as you call it in the book, the different kind of flavor profiles, I guess, of sweet, salty, sour and bitter. We won't get into all of those specifically. But I kind of found surprising was why children love sweets. It kind of seems obvious at first glance chocolate's delicious, right? But there's actually some really deep reasons why our bodies are attracted or repulsed against those particular flavors, right?
RACHEL HERZ: Yes. So and if I just could correct you, flavor is actually when we have the aroma with the taste. So taste is just the pure sensation of salt, sour, sweet, and bitter. So if you just had sugar in your mouth, that would be the taste of sweet. But if you had a lemon candy in your mouth, the flavor would be the lemon plus the sweet, so the lemon candy because the lemon part is coming from the sense of smell, the aromatics of that.
CODY GOUGH: Got it.
RACHEL HERZ: And so, like I said before, the real basis for these attractions come from our need for carbohydrates and also from the point of view of avoiding things that taste bitter. That's to avoid things that tend to be toxic. Because in nature, things that are poisonous or spoiled tend to have a bitter taste. They tend to be alkaloid in nature. That's from the point of view of the pH scale.
And so that's a signal that these things should not be eaten. And people vary with respect to how sensitive they are to bitter. They actually vary with respect to how sensitive they are to all tastes. You've probably heard of the term super tasters or tasters or non tasters.
And supertasters are extremely sensitive to bitter. They're also sensitive to all the other tastes more so than non tasters, and they get more creaminess from fatty foods. They get more sting from hot peppers.
And they have more taste buds on their tongue than tasters or non tasters do. And so this means they usually need less sweet, less fat. They like less hot food and also do not want to eat much bitter.
The downside to that is that people who are avoiding bitter foods could also be avoiding some of the healthy bitter foods, like the leafy greens that are also bitter. And there's been shown to be a correlation between being a super taster and a higher incidence of some kinds of cancers.
And on the flip side, though, with respect to liking sweet, you don't need as much sweet. But the one taste that super tasters actually like more of than any other is salt because salt actually blocks bitter taste. And so supertasters who've learned this tend to put more salt on their foods. And the more salt you use, the more salt you like and the more salt you want.
ASHLEY HAMER: Understanding that you shouldn't go overboard on the salt, there are plenty of ways us non supertasters can use salt's bitterness blocking powers to our advantage. There's a reason beer tastes so good with pretzels and peanuts. As Dr. Herz mentioned, the ions in salt actually block many of the receptors on your tongue that detect bitterness.
There's evidence that your brain actually perceives bitterness and sweetness as opposing forces. The more bitter something is, the less sweet it tastes and vise versa. Salt also changes the chemistry of water, helping it release odor molecules so you can sense them more fully. So if you sprinkle salt on something bitter like grapefruit or a cup of coffee, you can cut its bitterness while boosting its sweetness and aroma. Try it out.
CODY GOUGH: So we've talked about why we eat the things that we eat, but how about why we eat how much we eat? So what's the secret to resisting that second or third plate at the all you can eat buffet?
RACHEL HERZ: So here's another factor where the environment really plays a really big role in how much we eat and what we're doing when it comes to food. And so we are inherently lazy. And food is inherently attractive. And if it's in front of us, like literally within arm's reach or just a few steps, we're much more likely to engage in it than if we have to make more effort.
So if you have candies on your desk or a bowl of potato chips right in front of you while you're watching TV, that's a bad idea because it's very easy to just put your hand in. And also while we're doing other things like watching TV or working and we're distracted from eating, we do not keep tabs on how much we're eating. We also don't feel the same degree of satisfaction from eating so we tend to eat a lot more.
So the first step is to move those kinds of things further away from you. And if you need to have something on your desk to munch on-- carrot sticks, celery, or whatever you want, so something where it's going to be relatively neutral to consume that. The point from the all you can eat buffet is that if you're sitting across the restaurant from that all you can eat section, you have to get up and walk. And first of all, you're also not directly probably seeing it right in front of you if you're sitting at the table right beside it.
And so this is what you want to try to do. It's sit as far away from the buffet as possible. And then you're just going to be less likely out of inertia to get up and serve yourself more. But if you're sitting right beside it, if you can see it, if it's very easy to just get up and give yourself some more macaroni salad or take another brownie, it's much more likely to take place.
CODY GOUGH: This actually reminds me of how animals consume food. Right, if you've got a dog, it doesn't matter if you just fed the dog. If you've got your dinner plate or a slice of pizza on a low table, the dog is just going to eat it because it's food, and it's there. And animals love food, right?
RACHEL HERZ: Well, we're animals, and we love food too. And so just in the same way-- I mean, the whole point is it's all based on survival. We need to eat in order to survive. And we need to do it a lot. It's not like we need to have sex in order to survive as well, especially from the point of view of a species. But that we can space out.
It's not like if we don't do it on a daily basis we're going to not see the light of day. And so we need to eat. And we need to eat at least once if not more than that many times per day in order to sustain a healthy existence.
Again, from the perspective of we do not evolve in a landscape where food was everywhere and we needed to be reining ourselves in and pulling back from the temptations of eating if we came across food, we needed to want to eat it. And so our dog even, though, it's also living in our well-fed environment and probably should not be eating the pizza and everything else that's in front of them and us because they've already had their meal, is in the same way program to see food, eat food and we are too. And it's where our higher capabilities of reasoning and our knowledge about what's going on around us and our decisions to impose some willpower and whatever else need to come into play.
CODY GOUGH: Oh, let's just kind of bring it back finally to the dinner table. And if I'm cooking dinner or I'm preparing food and even if it's reasonably healthy, what's my brain fighting against, and what impulses do I need to be aware of maybe so I don't make macaroni and cheese for the ninth day in a row, or I can plate it in a certain way or serve it in a certain way that'll encourage better eating?
RACHEL HERZ: So I would say the most important thing from the point of view of eating is to be engaged with what you are eating. And so not to use an overused word, but being mindful in the sort of smallest sense of that is just being aware of what you're eating, looking at your food, thinking about it, smelling and tasting, maybe even taking note of, is it making a crunch in my mouth?
And even if you only do this for the first bite, you're going to get more pleasure. Being engaged with it more is going to make you feel more satiated without eating potentially as much. And it's just going to be a more positive experience overall. So that's, I would say, the number one thing to do.
ASHLEY HAMER: Call it mindfulness or intuitive eating or dare I say curiosity, but paying more attention is a research backed way to avoid doing things, well, mindlessly. The problem is that even when you're not paying attention, the caveman part of your brain is. When you eat a cookie, it feels good. You get this pleasant rush of sugar that your brain recognizes as being important for your survival, and it makes a note to remember what this amazing treat was that made you feel so good.
The next time you feel bad, your brain goes, hey, I know what will make you feel good. And then before you know it, you're eating a cookie. It's like Pavlov's dog. Pavlov rang a bell every time the dog was fed. And soon, all it took was the bell to make the dog start drooling.
In your case, the bell or trigger is the bad feeling. The drool or behavior is eating the cookie. And the food or reward is the good feeling you get, which doesn't need to happen for you to eat the cookie. The same thing happens with more addictive things like tobacco.
In a 2011 study, smokers who were told to be curious about the act of smoking by paying attention to how it feels, tastes, and smells were more successful at quitting than people who followed a standard stop smoking program. You can do the same thing with mindless snacking. The full article about how curiosity can help you break bad habits is on curiosity.com.
RACHEL HERZ: The other thing, though, there's all these other aspects of the environment to be aware of. And one of them in addition to the distraction is the number of people that you're with. So if you're in a party scenario and you're eating or if you've made a dinner party for many people and you're sitting around the table, again, that's sort of issue of, well, we're all just sitting around the table, and there's the food. We finished our meal, but there's still food on the plates and so forth, and I can take another piece of whatever, sort of just to be aware that the availability of food is going to make us eat more.
The fact that we're with more people-- the more people we are with when we eat, the more we tend to eat as well except if they're strangers where there's a little bit of that effect but not to the same extent. And so again, just taking stock of your environment when it comes to the visual part of it, though, you're making a nice point where food that is plated well, that looks attractive is also more appealing than food that looks not as appealing when it's presented even if it's exact same ingredients.
So we get more pleasure out of eating things that look nice on the plate. And again, this may not have as much of an impact if you're just cooking for yourself. But certainly if you're cooking for others, that little bit of extra effort into making what appears on the plate look nice can have a big impact.
The music you play in the background can also have an impact. So there has been research which has shown that sort of the concepts of the music can imbue the food. So if you're listening-- and especially there's also research which has shown that this is a really powerful effect with wine. So the wine that you're drinking-- if you're playing sophisticated classical music will have a different sort of quality to it than if you're playing jazzy music or if you're playing melodious music or if you're playing hip hop music.
And so you can actually kind of transform certain of the characteristics of the food and the drink you're having by the ambient sound. And also loud fast sound. For instance, loud fast music is even, though, maybe trendy less pleasant to eat in. And people eat faster, and they leave sooner.
So that's one thing to be aware of in a restaurant environment. And really loud sound actually like sound on an airplane, although this doesn't really address your question, can actually also change how you perceive tastes. And what's really interesting here is that one of the cranial nerves that innervates taste is also the cranial nerve that innervates hearing.
And when we're in really loud sound like in an airplane that nerve is affecting our ability to taste in particular sweet and salty and those taste less to us. And so food doesn't taste as good on airplanes for more than just the reason that they're giving you bad food on airplanes.
CODY GOUGH: Wow. I'd like to wrap up with our final segment we call the curiosity challenge where I will now learn something from you that has nothing to do with your field of expertise, which is pretty broad. I mean, you've done a lot of research for this book and you know a lot of science. What is the question you came up with for me?
RACHEL HERZ: OK. What is icing in the context of hockey? [LAUGHS]
CODY GOUGH: Oh, boy. I believe icing is when you-- this is going to-- oh, boy, hockey fans are going to hate me. I think it has something to do with when the skater skids to a stop and like ice flies up into another player or something. I'm making that up.
RACHEL HERZ: Yeah, you're making that up. That's a good try, though. It's when a player hits the puck, and it crosses the middle line and then crosses the goal line of the opposing team without anyone touching it. So it goes flying down the ice all the way to the back boards, and nobody's touched it in between. And that creates a penalty.
So that's icing. But I thought it was funny because icing like cake icing. I was all proud of myself for coming up with a pun here so in addition to trivia. And that's the sport that I love because I'm Canadian.
CODY GOUGH: Oh, OK. Yeah, that makes sense. Well, now hopefully I can teach you something or give you a chance to showcase how much more you know. My question is, does tapping a can of soda really help keep it from exploding?
RACHEL HERZ: No.
[LAUGHTER]
That's going to be my mythbuster answer, is no.
[LAUGHTER]
What else do I have to give you? I wouldn't think so especially because if it were carbonated, that would seem to agitate the soda more if you were tapping it then if you didn't tap it. But I don't know the precise science behind it. But my answer is still no.
CODY GOUGH: Sure. Well, this is kind of a trick question. So, yes, tapping can work. And the reason is because when bubbles form when you shake it up because of turbulence, those bubbles tend to stick to the sides of the can. And the idea is if you can kind of free up those bubbles, then they'll rise to the top. That will form one big bubble that harmlessly escapes as a gas when you open the can.
So the problem is that when most people tap a soda can, they focus on tapping the top. But that neglects the bubbles clinging to the sides-- the walls and the bottom of the can. So that leaves them free to violently explode when the pressure is released. So the next time a can is shaken up and you want to make sure it kind of calms down before you open it, tap on the side of the can, and you may be able to help free those bubbles.
RACHEL HERZ: Well, thank you. Now I did learn something.
CODY GOUGH: Yeah, there you go.
RACHEL HERZ: I appreciate that.
CODY GOUGH: Sure. We've written about that on curiosity.com. We'll have a link to the full science in the show notes, has to do with surface tension and lots of other sciencey stuff. And we'll also have a link in the show notes to the book Why You Eat What You Eat, the science behind our relationship with food. It's really interesting and continues even more than we learned on the podcast today. But, Dr. Rachel Herz, I want to thank you so much for joining me on the Curiosity Podcast.
RACHEL HERZ: Thank you, Cody. It was great to be on.
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ASHLEY HAMER: It's time again for the extra credit question. This week's question comes from [? John ?] [? McGrath ?] who writes, "I've always heard that if you put hot water in your pet's bowl and place it outside, it would freeze faster than a bowl of cold water would freeze." Is that true? The answer after this.
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CODY GOUGH: So, Ashley, did you want to talk about that Facebook watch thing we're doing?
ASHLEY HAMER: Oh, yeah. I'm super excited about that.
CODY GOUGH: Facebook's new video platform has videos from and starring us.
ASHLEY HAMER: Yeah, we explain all sorts of stuff. Cody's first one was about how to win an argument online. And then I did one on why you remember more things from your teen years.
CODY GOUGH: And we have many, many more to come. So check back on our Facebook page every week. I think they're fun.
ASHLEY HAMER: You'll see just how tall Cody's hair is.
[LAUGHTER]
CODY GOUGH: You got me. You got me there. Maybe we'll even do a video on hair.
ASHLEY HAMER: Maybe we will.
CODY GOUGH: There's a tease. facebook.com/curiosity.com.
ASHLEY HAMER: Ready for the extra credit answer? [? John ?] [? McGrath ?] asked whether it's true that hot water will freeze faster than cold water. And weirdly, it's true. This phenomenon is called the Mpemba effect in honor of the Tanzanian 13-year-old who discovered it in the 1960s. Scientists don't actually know what causes it, but there are a lot of theories.
One is that hot water evaporates faster than cold water, so it loses mass faster. When you have less mass, you don't need to lose as much heat to freeze. But the effect still works in closed containers where there's no evaporation, which is a problem.
The most recent theory was published in January of 2017. And it says that heating breaks the weak hydrogen bonds in water molecules, leaving a bunch of molecules with strong hydrogen bonds that are super ready to arrange themselves into the crystalline structures of ice. Other scientists couldn't replicate those findings, though. Maybe the best answer is to try it yourself. Put hot and cold water in the freezer and see which freeze is faster.
CODY GOUGH: You remember Siberia, when it was super, super freezing in Chicago?
ASHLEY HAMER: Yeah.
CODY GOUGH: I did the thing where you boil water and threw the boiling water off the balcony because supposedly it would freeze before it hit the ground. But you didn't do that.
ASHLEY HAMER: No, I didn't do that. I'm smarter than that. [LAUGHS]. I don't want to burn myself.
CODY GOUGH: That's perfectly fair. I did make sure there was nobody standing under my balcony when I did that.
ASHLEY HAMER: That's good.
CODY GOUGH: I'm Cody Gough. And thanks for listening to the Curiosity Podcast.
ASHLEY HAMER: And I'm Ashley Hamer. See you next time.
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SPEAKER 1: On the Westwood One Podcast Network.