Science Talk

Putting Food on the Table: What to Eat

In this episode New York University's Marion Nestle talks about her article in the September issue of Scientific American, called "Eating Made Simple." Plus, we'll test your knowledge of some recent science in the news. Web sites related to this episode include;;

Welcome to Science Talk, the weekly podcast of Scientific American for the seven days starting September 5th. I am Steve Mirsky. This week on the podcast: More from the September single-topic issue of Scientific American magazine devoted to food, feast and famine. We’ll talk with Marion Nestle, author of the article "Eating Made Simple". Plus, we'll test your knowledge about some recent science in the news. Marion Nestle is the author of the book What to Eat. She holds a master's degree in public health and a doctorate in Molecular Biology and she's the Paulette Goddard professor in the Department of Nutrition, Food Studies and Public Health at New York University. She is also a professor of sociology there. By the way, this interview is farm fresh. We spoke September 4th at her office at N.Y.U.

Steve: Professor Nestle, good to be here.

Nestle: Very nice to be here.

Steve: Let's talk about this article in the September Scientific American. One of the key points in the article is that it's very difficult to do nutrition research, about human nutrition. Why is that so difficult?

Nestle: Well, everybody eats, first of all, and people eat enormously complicated diets. And these days, probably half of the meals [are eaten] outside the home, where they are being prepared by somebody else. So just to find out what's in a diet or what people are actually eating is an intellectual challenge of phenomenal proportions. You ask people what they eat, they can't remember, they lie, they forget, they tend to forget things that they are eating standing up or in funny places or if they go to a supermarket and there is [are samples for] tasting; they are not going to remember that. And so, it's hard to get people to remember what they eat. They certainly don't know the quantities that they eat—the tendency is to underestimate. And then once you have the information about what people are eating, you then need to translate that into nutritional terms, which involves going to a nutrient database, usually the one that's developed by the Department of Agriculture, which looks at the nutrient composition of foods; and here you are saying well, let's see, I had an apple for lunch … well, what kind of an apple? Where was that apple grown, was that apple grown in the United States locally or did it travel 3,000 miles or did it come in from New Zealand and sit on a truck, or sit on a boat for a couple of weeks? You know, it's really hard to know; and the nutritional level of that food will change very much depending on the variety, the storage conditions, and a lot of other factors. So it's very difficult to get anything approaching accurate information. Now a lot of people tend to dismiss nutrition research out of hand, and say, well, it doesn't mean anything because it's too complicated. I say, it is an intellectual challenge and it deserves the finest scientific minds to look at these kinds of questions and to try to make inferences from the kind of data that we have available.

Steve: So many of the studies though are about single nutrients and that tends to drive people crazy. And what do we do about those as opposed to those kinds of retrospective studies of a large population, that can be so difficult to work with because you have to tease out what the real information is.

Nestle: Well, yes, I mean, people eat complicated diets, so you look at them and you say, gee, it looks like people who eat a lots of fruits and vegetables are healthier than people who [don't] aren't —what is it about fruits and vegetables that is making those people healthier? And so you think,well may be it's the fiberand that was thought—for [a] long time people thought—it was the fiber; maybe it is lack of fat, maybe it is one or another particular vitamin or mineral. And so scientists have looked at each of those one by one and come out with some kinds of results that sometimes appear meaningful and sometimes don't appear meaningful—almost all of those kinds of studies require very sophisticated statistics—to get kind of a result. It isn't an all or none result s . It is usually a result that has a statistical significance that is rather low so that you might have a 20 percent difference ( UNCLEAR( 4.17) or a relative risk of 1.2 or something like that; and so it is easy when you have risks that are so small or the differences are so small to have one study show one kind of result and another study show a different kind of result. And so the results of single nutrient studies need a lot of interpretation because the nutrient is taken out of food context. The foods are taken out of the diet context and then the diets are taken out of the lifestyle context and may have nothing do with food at all and may have to do with how active people are or how much they are drinking. It probably doesn't have a whole lot to do with genetics. When they have looked at the genetic components of nutrient studies it tends to be a very, very small component of the health risk [that] allow for these behaviorally induced diseases.

Steve: You make me wonder, maybe I'm to blame, maybe the science media is part of the problem, because if we know that a diet high in fruits and vegetables is generally healthful and then we try to tease that out, if the scientist tried to tease out the details—which is their job and they should keep doing that—but if the science press or the general press continues to report breathlessly on the individual-component research, does that not confuse the consumer without the bottom line of, you know, don't forget just a lot of fruits and vegetables is really the way to go.

Nestle: I think consumers are enormously confused about nutrition and health. They tell me that all the time. And they find the research absolutely obfuscating. I mean, they are just stunned by it and their response to it is: You nutritionists change your mind all the time. First you tell us to do this and then you tell us to do that and then you tell us to do [an]other thing. What are we supposed to do? None of it means anything. We are just going to throw up our hands and do whatever we please. And I think that's very unfortunate, because if you read through all the hype about one nutrient or another, the bottom line is the same and hasn't changed since the first set of dietary recommendations for chronic disease started coming out in the mid 1950s. I mean I have this book on diet and heart disease that was written [in 1959] by Ancel Keys and his wife, Margaret, that had dietary recommendations in 1959 that looked like they could have been written yesterday.

Steve: And he lived to be a 100.

Nestle: And he lived to be a 100. He just died a couple of years ago. Although there are may be other reasons. (laughs)

Steve: Sure, sure.

Nestle: But the diet—those recommendations right from the beginning were to eat sensibly, eat a lot of fruits and vegetables, don't overeat, you know, be physically active, relax, don't worry, have a good time, enjoy your food. I mean, it was very, very good advice.

Steve: Isn't it interesting? Do we enjoy our food less with all the information that’s constantly coming at us?

Nestle: Well, I suppose it depends on who you are. I enjoy everything I eat. (laughs) But I certainly hear from people who are terrified of eating foods that they think are going to be poisoning them and trans fat is certainly the most obvious example of that. People think that trans fats are poison and that if they eat something with trans fat, they are going to die on the spot; and if a food doesn't have trans fat, it must be health food and it doesn't have any calories.

Steve: Right.

Nestle: If I had one thing then [that] I would want people to understand [it] is what calories are about. I think they dominate issues of nutrition and health these days and they are very hard to understand. Scientific American ought to do an article on calories.

Steve: Just calories. What they are? What they mean and how much you actually take in on a daily basis and how much you expend?

Nestle: Exactly. And also perception of calories. Because as these studies come out that show that people think that foods advertised as health foods are lower in calories, it becomes clear[er] and clear[er] that people don't understand what they are about and they are hard to understand, they are very abstract. You can't see them, taste them, or feel them; they can only be measured in very complicated ways. So it's understandable, why people are confused about them, but I think if people understood more about calories, then nutrition would make a lot more sense to everybody.

Steve: I recently spoke to Brian Wansink at Cornell.

Nestle: Yes, indeed.

Steve: And he studies the perception of calories, at least to some degree.

Nestle: Yes. He's just come out with this—or he is about to come out with—this fantastic study on people's perceptions of foods in McDonald's and Subway.

Steve: Right. We talked about that a little back.

Nestle: And you know his work clearly shows that people think there are fewer calories in the food at Subway, even if they [there] are not. (laughs)

Steve: Let's talk about calories. There is a specific statistic in your article, that's really fascinating and that's [that] in about the last [three] 3 decades, the average number of calories produced in this country per capita has gone up from what was it, 3,200?

Nestle: Thirty-two hundred in 1980 to 3,900 now. Yes it is an increase of 700 calories in the food supply. That's how people are actually eating. That's what is available for consumption and it is a figure that includes what is produced in the country—less exports plus imports—averaged across the entire population, men, women, and little, tiny babies.

Steve: That's what Americans are eating or have to eat.

Nestle: That's what Americans have available to eat, that's what they are eating , so they have available to eat .

Steve: We are not up to 4,000 calories a day yet to eat.

Nestle: (laughs) No, I hope not. It is roughly twice average need, and for the population as a whole, and so what that means is that you have such a surplus of calories available that if you are in the food industry or in the food business your job is to sell it in an extremely competitive environment. And I think that this governs, what's happening in our food supply right now: Food companies are just struggling to get their foods sold in this extremely competitive food environment. And it's not only that food companies have to sell it in order to make a profit but because of the way our food investment system works—or investment systems works in general—they have to grow; they have to report growth to Wall Street every 90 days; that's really hard to do, when you are trying to sell your product in an environment in which there are twice as many calories available. So and all of this happened starting in the early 1980s, which was just about the time when obesity rates started to rise. So what the food industry had to do in order to sell those calories occurred in parallel with rising rates of obesity, and we can argue about where cause and effect come in, but the trends certainly occurred in parallel, and I think that what happened was that food companies started figuring out ways to sell more food that were new for Americans, portion sizes got bigger, food started being sold in places where it had never been sold before. My favorite example is when did it become okay to eat in book stores? You know, I can remember when I came to New York University in 1988, there were signs all over the library, very clever ones telling people you can't eat here; and there were guards at the door, if they saw you bringing in food or drink, you were not allowed to go in. Now there are two cafes in the library—and that's selling more food in more places. It became socially acceptable to eat more often, it became socially acceptable to eat on the run, it became socially acceptable to eat large portions of your daily calories in automobiles, it became socially acceptable for kids to drink soft drinks on their own and it became socially acceptable to have vending machines in schools. These are all things that happened in the last 25 years, in parallel with rising rates of obesity. So we have a social environment that promotes eating more and not less and if we are going to do something about obesity we need to change the social environment, and that's hard to do.

Steve: So how do we change the social environment though?

Nestle: Well, we will do it in the way these changes always take place—you do it through education of the public; you create demands for different kinds of foods; you teach parents to go into schools and look at what their kids are eating and then do something about it; you change policy so that it becomes more difficult for food companies to advertise to children; you stop them from marketing junk food to kids using cartoon characters. I mean, all the things that are going on now are examples of policy approaches to trying to get something done about obesity. Let me tell you, it is not going to be easy to do that because they're powerful industries, who have, as their general interest, getting people to eat more food than last [year]—that's just the way our investment system works. So I am sure that there are plenty of people in the food industry who wish that they could do better, but they can't keep the bottom line up and this is most obviously seen in the whole issue of marketing food to children.

Steve: You spent a year in supermarkets researching your book, What to Eat.

Nestle: I did.

Steve: What was that like?

Nestle: Oh! It was more fun than anything. I can't remember when I have had so much fun doing research. I'd just go to supermarkets and read labels and look at the way the store was laid out and just pretend I was an anthropologist (laughs) practicing without a license and examining how people interacted with the foods in supermarkets and what everything in supermarkets told you about important food issues. And then I went home and started to do the research to try to understand why the store was laid out the way it was and what the labels meant and what the rules were and what the labels could say, mostly to try to make it easier for people to navigate their way through the kinds of choices that they are confronted with, when they go in to a supermarket. I was astounded by the complexity of the choices.

Steve: Obviously you want everybody to go read your book, but if somebody listening wants to get a jump on reading the book and they go into a supermarket, what are some little things they can be on the look out for that maybe they would not have noticed otherwise?

Nestle: Well, the first thing to look [at] is the way the store is arranged. The first thing you go into to the right or the left is the produce section because that is something that research shows draws people into the stores and makes people think that they are dealing with real food. The real foods—that is, the meat, the dairy, the produce—are always in the preferable aisles of the supermarket. You have to walk all the way around the outside of the store in order to get them and that’s for two reasons: One because it is easier for the store to stock them; but also because almost everybody who comes into the store [is] going to be buying milk, and the milk is always going to be in the far diagonal corner from the entrance—very good for your exercise program, but not so good if you're in a hurry. And then the junk foods, the processed foods, are going to be in the center aisles, and they [these] are very, very, very long and the reason that they are very long is because the research shows that the more products you look at, the more you buy, and that is a rule of supermarkets that research backs up over and over and over again. So the object of the game from the stores' point of view is to make the aisles long enough so that you will see as many products as possible but not so long that you will run screaming from the store in frustration. But everything about the store is designed to get you to see more products and to see more of the products that are most profitable. And the products that are most profitable are located at prime real estate—that is at eye level at the ends of aisles and at the cash registers where you cannot possibly miss them, and companies pay the stores in order to put their products in those places.

Steve: A lot of people might not know that that the companies Coke and Pepsi are paying the stores to put Coke and Pepsi in good places.

Nestle: Not only that, but they're also promising the store that they will advertise in local newspapers and in local venues at the same time. So it's not an accident that products like soft drinks which are nothing but sugars of one kind or another in water and are very, very profitable have entire aisles devoted to them.

Steve: Now, one of the particular products you mentioned in the article is the monster thick burger—so can we just use common sense, and if it is called something like monster thick burger that's probably a clue that it is pretty high fat.

Nestle: Well, that's certainly a clue that it is loaded with calories, and I think that it is aura for a lot of people: Ah! It is going to be delicious and I am just going to love it and I am going to have lots of calories in a hurry; and that's what lot of people want and it is not going to cost much.

Steve: I remember somewhere somebody once said—maybe it was my own mom, I don't remember—it is hard to eat unhealthfully for more than 29 cents of [a] pound. This was back a ways and what it meant was, you know, if you're buying fruits and vegetables chances are, it is more inexpensive, it is less expensive than buying the processed, it is cheaper to buy potatoes than potato chips by weight.

Nestle: Right, but our food system has changed and right now because of farm policies that support the production of cheap ingredients in processed foods, processed foods are much cheaper per calorie than our unprocessed foods and vegetables per calorie; so that if you look at the studies that have been done, if you look at the cost of processed foods, it is a much greater bargain for somebody who is poor to buy junk food than it is to buy foods that are fresh.

Steve: That's really fascinating; that’s a major switch in the history of humanity then, isn't it?

Nestle: It is indeed. And so fruits and vegetables are widely perceived as being as expensive because you do no get very many calories added to them; and if you are poor and hungry, you are going to want [as] is many calories as possible, even though when you think about it, a potato costs practically nothing per pound and potato chips are 10 times more expensive.

Steve: But a bag of potato chips—even a single serving bag—might have 250 calories.

Nestle: Because it has got oil in it so…

Steve: And a whole potato is what, 100?

Nestle: Right! Exactly, so, because they have been fried in oil, and that's where lot of the calories are.

Steve: So again, you know, you would obviously want people to read the book, but shorthand—fruits and vegetables; it is the old formula: Fruits and vegetables have fewer calories, smaller portions, enjoy what you are eating.

Nestle: I have my mantra: Eat less, move more. Eat fruits and vegetables and don't eat too much junk food it is and enjoy what you are eating. It is simple as that.

Steve: And I was in Vermont over Labor Day weekend and fresh corn and fresh vegetables is really delicious.

Nestle: It's really delicious.

Steve: A lot of us get out of the habit of eating fruits and vegetables, but if you find the good stuff…

Nestle: While [Well] those of us on the East Coast are so deprived except at the height of summer. People in California are so lucky; I hope they appreciate it.

Steve: Professor Nestle, thanks very much for your time, I appreciate it.

Nestle: My pleasure.

Steve: Marion Nestle's article in the September issue of Scientific American is called "Eating Made Simple". It is available free at our Web site, And the Science Talk episode with Brian Wansink talking about the Subway-McDonald's study was the June 20th episode. You can find it in the Science Talk archives on the SciAm Web site.

We will be right back.

(Male voice: Wandering around? Visit Scientific American mobile edition on your Web-enabled mobile device. Go to for the latest science news and analysis, plus daily trivia questions; that is on your mobile's browser.)

Steve: Now it's time to play TOTALL…….Y BOGUS. Here are four science stories; only three are true. See if you know which story is TOTALL…….Y BOGUS.

Story number 1: Researchers have tested a noninvasive device that can heal a punctured lung with ultrasound. Emergency workers might be able to use the device at the scene of an accident.

Story number 2: Rock and pop stars are more than twice as likely to die an early death as the rest of us.

Story number 3: Secondhand smoke can kill people but studies on pets have shown no ill effects from living with smokers.

And story number 4: Women who are hypnotized before breast cancer surgery needed less anesthesia.

Time is up.

Story number 1 is true. University of Washington engineers are working with physicians on the ultrasound device to seal punctures in lungs. In tests reported in the Journal of Trauma, the device sealed 95 percent of incisions in pig's lungs within a couple of minutes.

Story number 2 is true. Rock and pop stars are twice as likely to die prematurely as are the non-famous, especially in the years immediately following their rise to stardom. That's according to a study in the Journal of Epidemiology and Community Health. For more, check out the September 4th episode of the daily SciAm podcast, 60-Second Science.

And Story number 4 is true. Women who underwent hypnosis prior to breast cancer surgery required less anesthesia. The research appeared in the Journal of the National Cancer Institute. For more, check out the August 30th episode of the new weekly SciAm psychology and neuroscience podcast 60-Second Psych at

All of which means that story number 3, about pets being immune to secondhand smoke is TOTALL…….Y BOGUS. Because a Colorado State University study found that dogs—especially long-nose breeds—that lived with smokers have a higher chance of getting nasal tumors than dogs in a smoke-free environment did. Meanwhile, cats living with smokers have a higher risk of mouth cancer, according to a study from the Tufts College of Veterinary Medicine, probably because when they groom themselves, they are looking [licking] up smoke particulates that settle on their fur. So don't puff on your pets.

Well that's it for this edition of the weekly SciAm podcast. Check out the blog, Weird Science, and the latest science news at the Web site,—and you can write to us at For Science Talk, the weekly podcast of Scientific American, I am Steve Mirsky. Thanks for clicking on us.


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