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RAY SUAREZ:Welcome to a special global health NewsHour forum.I’m Ray Suarez.
Obesity used to be seen as a health problem of wealthy countries – countries like the United States and Britain – where food is plentiful, most of the population can afford lots of it and lifestyle changes have cut physical activity levels.But low- and middle-income countries are also seeing a dramatic rise in obesity, particularly in urban areas.
Last week on the NewsHour, I explored this trend in China, where 19 million people are now considered obese. But that rate is expected to grow by 30 to 50 percent a year. By 2015, the World Health Organization is predicting there will be 700 million obese people around the globe.
So what’s happening in societies where rates are rising?And what are the biological factors contributing to global weight gain?
To address those questions and others, we have with us Dr. Barry Popkin, director of the UNC Interdisciplinary Obesity Center and author of “The World is Fat: The Fads, Trends, Policies and Products that are Fattening the Human Race,” and Dr. Michael Power, a research associate at the Smithsonian National Zoological Park and the American College of Obstetricians and Gynecologists. He’s co-author of “The Evolution of Obesity.”
Well, we’ve got a lot of questions, as you might imagine, because this is such a pressing topic for so many in so many places.Let’s start with some of the basic ones.
Kiko writes to ask, “What is it that makes human beings overeat the wrong foods? How does the human brain get triggered to overeat certain foods? What is in human brains that leads us to override our ability to control our eating habits? Do animals have this problem? If not, why not?” Dr. Michael Power?
MICHAEL POWER, co-author, “The Evolution of Obesity”:Those are a set of really, really good broad-ranging questions.One of the things is, food is obviously rewarding.All animals enjoy eating, we enjoy eating; we eat food for a lot of different reasons.And there are clearly interactions between what we eat and chemical signals that get sent to the brain and interactions in the brain that react to this sort of rewarding stimulus.
So there are certain things – high-fat, high-sugar foods do certainly seem to – in many animals and, it seems, in human beings as well – interact with what’s called the dopamine system in the brain, which is usually associated with the rewards systems. So food can be rewarding in that sense.
So one of the things that I always like to tell people when they worry about this overeating is that human beings eat food for many reasons. We don’t just eat food for nutrition. So many of the things looking at appetite have always sort of settled on this why-can’t-we-stay-within-energy balance? Why don’t we simply eat only what we need to? But the point is, we eat for more reasons than just for nutrition and health.
RAY SUAREZ: Dr. Barry Popkin, it would seem that it’s just been the blink of an eye in human history that constantly overeating was even an option.
DR. BARRY POPKIN, UNC Interdisciplinary Obesity Center:That’s right, that’s right.We’re really talking about a mismatch between the biology that’s been created, as Michael was describing, over, really, hundreds of thousands of years.And all of a sudden, modern technology found ways to shift it from drinking water to sugar-sweetened beverages, and the same with our inactivity and the same with the fatty foods.
This is all modern, post-1950, learning to change our food supply and manipulate it in very quick ways and make it accessible to the globe. So we’re talking about changes in an evolutionary sense that are not even in the blink of an eye. It’s kind of like a nanosecond, as they would say.
RAY SUAREZ:Well, I guess in human societies, there has always been a small number of people – or, frequently been a small number of people – who have the option of overeating, but the reality of daily life for the broad mass of people in societies around the world was that overeating was not an option.And being hungry was an episodic reality as well.
BARRY POPKIN: That’s right, and being hungry probably led to the overeating. We know it does. We need it to protect reproduction and we need it to do lots of things that Michael could talk about.
But to me, to think in the modern reality, I started working, for example, as you mentioned, China. And I started doing national surveys there in the ’80s. No one was overweight. But today, almost 30 percent of Chinese adults are overweight. Chinese kids – five or six in the last four years – have grown so much, they’re actually fatter at the highest level than our kids, and they weren’t five years ago. It’s just such a huge shift in the access to food supply and the income and distribution system to get it to everybody, while taste and biology haven’t changed.
MICHAEL POWER:And one of the things I would add in here is a big thing that has changed in human eating is that we have completely separated from exertion.It used to be through most of our evolutionary history, if you wanted to eat, you had to exert; you had to get out there and get the food and do actual hard work and expend energy.Now, we’ve basically taken that part of the equation out.Basically, eating is no longer even related to exertion in many cases.
RAY SUAREZ: Shawn writes to ask, “Are some ethnicities or countries more prone to be obese? Or with enough money and access to fatty foods, does everyone eventually get fat?” And I think since we’ve seen this problem rise in certain places sooner than others, it’s an interesting thing to think about. Who wants to pick that one up? Dr. Power?
MICHAEL POWER: I’ll start with just saying that there are several different issues that get in to this. One is, we think there may be some, amongst different peoples of the world, a different propensity to put on fat and also a different propensity of how that fat is going to affect health. And that’s actually, in some ways, a more important issue – the fact that we may have variation in the reaction to excess fat – that made health issues in there.
If you eat more food than you’re going to burn off in calories, everybody will gain weight and everybody will go that way.So I don’t think there’s a broad difference in that way.But it’s also clearly true, in this society, we don’t all get fat.There are some people that seem to be more vulnerable to gaining weight systemically than others.
BARRY POPKIN:But the other side of Shawn’s – of that question is we have many populations today, like, take some of the Western Pacific islands, take Mauritania a few years ago, take others, that for a range of reason, fatness was good.Girls in Mauritania used to be fattened when they got to puberty because that made them more desirable for men.And now, the queen is stopping that and they’re cutting it.
So I’m not sure that there’s a thinness gene or that – I think there are different ways people can deal with the food supply.Some can control what they eat; some can do more exercise to deal with it.The complexity of this whole topic is even if you don’t get diabetes when you get fat but you just are fat, it affects your whole system.
And pretty soon, even those places that have lower levels of diabetes for the fatness, like some of the Western Pacific and a few other locations, they can’t move because the weight is kept controlling them.So we’re in a world today where we see many populations going around in computerized cars – little chairs – because they can’t even move.
And so we have to realize fatness is not just going to affect our weight.It’s going to affect our bone health; it’s going to affect our mobility; it’s going to affect our ability to function in daily living in that we don’t seem to know if there’s a limit.
And despite people saying, oh, we’ve reached our limit in this country and that, the countries that haven’t addressed it, like the U.S. or a lot of the Asian and other countries we’re talking about today, they’re just accelerating and accelerating.The rate of increase of overweight actually in most of the world, from a new paper I have coming out, has accelerated in the last decade.So among the four or 5 billion people that are outside the U.S. and Europe and Japan and South Korea, they’re getting fatter quicker.
RAY SUAREZ: So wait, if we took a Tongan or a Samoan, a Masai herder and an American Indian from the Southwest and put them on the same diet, one wouldn’t put on weight in a different way from the other?
MICHAEL POWER: I think you’d get a lot of variation within those populations as well, but you would also see – in other words, you wouldn’t be doing one. If you had a thousand of each, you would probably see different effects between those groups.
BARRY POPKIN: But the effects on disease would be different than the effects on their weight. And it starts with their height. When you have a very tall person, you can add a lot more weight before your mobility and such is affected and you get really fat. And the Masai are taller. But, they’re gaining weight now – the Masai going into urban areas and slowing down. It’s not like these populations that historically we thought of as being tall, lean, or short and lean.
In India, we’re getting in the squatters where I lived 20, 30 years ago, in those populations, the 10 to 15, now up to 18 percent of the adults in those poor, urban areas are getting heavy. And it’s happening in rural India.
MICHAEL POWER:And Barry made a very good point about there really – no good evidence for there being a thinness gene.And if you look at it from an evolutionary perspective, there is probably a lot of genetic variation in our population that would lean us toward gaining weight and relatively little towards keeping people from gaining weight.
There’s an asymmetry in how selection would have acted in the past. And in the past, many of these traits would simply not have been expressed because there was no option, no ability to cut your energy expenditure to such a low level and to get access to so much food that you would end up gaining that much weight. So there’s going to be an asymmetry in the situation, in which there’s probably far more genetics that would lead us to overeat and to put on more fat than there is for us to stay lean.
RAY SUAREZ: One of our online visitors asks: “I am the third generation of obese adults in my family. Considering some genetic factors, our processed-food environs and a sedentary lifestyle, what hopes do the obese, by genetics, have to eat like normal humans?”
First of all, given what you’ve just been saying, is our questioner – Metuchen Blues – even right when she refers to obese by genetics?
BARRY POPKIN:My perspective is, no.We have only identified fat genes for a handful of people that directly cause this.We have lots of leads, but it’s a very complex issue, just like diabetes.And there are probably multiple genes that go together.What we have are family behaviors and proclivities of parents who are heavy to have heavier offspring and to have different dietary and activity patterns that create the problem.
But we have no real clarity that the comment is correct that there’s a genetic side. It’s probably more a combination of a whole lot of behaviors that go on and that are intergenerationally passed through, both in terms of your weight and height at birth and onwards. And even in the fetal environment.
RAY SUAREZ: But is she right – is she onto something, Michael Power, when she talks about, what hope do we have to eat like normal humans? If you have been nurtured, grew up in a household that laid down your relationship to food for your adult life and laid down the way you think about food and the way you process it, is it hard to change that once you’re an adult?
MICHAEL POWER:Changing behaviors is always very difficult and hard, but the human mind has the capacity to do that.And getting information and having motivation, certainly people can do that.I agree with Barry that, in terms of looking at straight genetics, at best we’ve maybe found genetics that maybe relate to 5 percent of the population that’s getting obese.So it’s a relatively low number.They’re continually finding more, but again, it’s probably multiple gene effects.
The one issue Barry did relate to, in utero effects, there is a worry in there in that you have not just changes in the genetics and the DNA itself, but changes in the expression of the DNA, what we call epigenetic effects.And those could be passed in utero and those can be inherited down the – from mother to offspring.And so that may be changing metabolism in such a way as to increase the probability that a person will put on fat.
But we’re getting a better understanding of what some of the proximate mechanisms are and there’s certainly always hope, in that sense.The main thing I would always say is, worry about exercise and cardiovascular fitness, since that’s actually an independent risk factor for health, as well as anyway – but people raising their energy expenditures would probably be one of the best ways to start.
RAY SUAREZ: As you might imagine, we got a lot of questions about China, given the series last week. Max writes, how has food changed in China? In addition to food changes, does pollution – air and water – and additives, fillers, including nonedible plant material, have an impact on both lifestyle and fitness? Barry Popkin?
BARRY POPKIN:Probably the two most important changes for creating the hypertensive, diabetic, heavy Chinese of today are really the massive change in the food supply – and by that, they shifted from not eating very much fat to consuming an enormous amount of cheap vegetable oil.
And they’ve been shifting more and more to dense – they had no sugar in their diet in the ’80s – essentially, one or two grams a day, the lowest in the globe.Today, China has a pork reserve and a sugar reserve.And it has been sold on sugar in the diet and it’s really accelerating.That’s a shift from water to sweetened beverages and adding sugar to lots of foods.So the fat and the sugar and the shift away from healthy eating and drinking are pronounced.
But at the same time, there’s not a single place in China – urban or rural, any province – where the technology of how they move at work and what they do at work – and I mean little tiny tractors that cost $100 for a farmer, or ways to cut backbreaking work in construction and mining – have changed.In the urban sector, the kind of activity has gone down to a fourth or fifth, in terms of metabolic equivalence, from what it was in the ’80s to today.Also, how they move – they aren’t biking anymore and walking.They’re taking buses and using tractors.
The same at home, home production:The amount of time spent on food in China, in producing it and getting it, has gone down by about a fourth of what it was.And the same for leisure.All of these have had a marked effect on the decline.The difficulty is they didn’t cut their calories.
Now, you add to that – there are pollution effects in different parts of the country.There are chemicals in the food supply.Those have a lot to do with certain cancers and certain cardiovascular problems, but they only exacerbate the energy imbalance and the weight problem for certain kinds of diseases.
So you start off with this huge change in lifestyle.In two to three decades, the Chinese – really, in two decades – have gone from no overweight to close to a third of adults – when I have my new data, it’s actually going to be, when I publish it, higher than that – the data we just collected last year – and for kids, going from thin kids a decade ago to really heavy ones today.
Every school in China today – rural areas are growing faster in obesity than urban areas.And now you find the schools there have the same vending machines we do here and they don’t have water supplies anymore.It’s a remarkable change in the last decade, even.
RAY SUAREZ: Michael Power, is there a slingshot effect? When you look at the litany of factors that Barry Popkin just laid out, when you talk about a society that, throughout history, knew episodic food insecurity, even famine, where millions died – does the bounce that you get become even more significant when getting food is easy, when calorie-dense food is more plentiful? Have their bodies been programmed to lay on fat even faster to get them through the lean times – but there aren’t going to be any more lean times.
MICHAEL POWER: It’s certainly quite possible. I think the quicker reaction that’s going to happen here, though, is probably in the minds of the older people that passed on behaviors and ideas about food and about what’s good, based on those sorts of things.
RAY SUAREZ: How do you mean?
MICHAEL POWER:Well, you get it in the United States in some Hispanic groups, in which they like the fact that they’re getting fat babies, now, and fat children.And Hispanic immigrants coming in – there’s good evidence that they want to have the richer foods.The richer foods, to them, turn out to be high-fat foods and high-sugar foods – the foods that they were not able to have when they were younger and when they – before they came to this country.
And so this is a change in which they perceive an advantage and a benefit to these high-calorie foods.And in a sense, if they were still working extremely hard and exerting extremely hard, that would be absolutely true.But they’re passing on a belief that these are the important and valuable foods to have.
Now, certainly, you also do get an evolutionary aspect in that too, in that these things were very rare in the past.And what’s rare is, in a sense, considered valuable and then people inevitably have high motivations to try to get them.
The other thing that I see is that if you just – Barry alluded to that, of just adding oil and simple sugars into the diet – you’re so increasing the nutrient density and you’re taking out, in a sense, taking out some of the water of the diet in that way, that the mere amount of food that you used to have to eat – if you ate the same amount of food by weight that you had to eat hundreds of years ago, it’s going to be massively larger numbers of calories.So quantities of food that you had to eat in the past because the foods were much lower in caloric density are absolutely not appropriate now, even if you are exerting a fair amount.
RAY SUAREZ:Ms. Jamaica asks:“I wonder how much of China’s obesity problem can be attributed to globalization and the importation of non-local foods?”
BARRY POPKIN: That’s a rather complex issue, but the simple answer is, yes and no. By that, I mean that the technologies that brought to China Wal-Mart. They didn’t start with Wal-Mart. They started with their own equivalent and their own equivalent of a 7-Eleven. And one of the top four chains in the world is a Chinese chain that’s just like Wal-Mart. And it’s just in China.
Similarly, Coke isn’t the dominant beverage company in China nor is Pepsi.There are Chinese equivalents.But they use the same technology that we’ve developed and they did it themselves.The same goes for the – how they’ve computerized their world, how they’ve automated it, how they’ve moved to cars and vehicles and buses and trains.That’s available technology.
The difference is, it’s starting in the ’80s the Chinese economy opened up. They opened up to Western goods and Western technology and it hit them lickety-split. And they adapted very quickly. Nobody wants to do back-breaking work. Nobody wants to eat rice and vegetables all their life if they can add oils and sugars and tastier foods. And what happened is it changed day and night.
But it didn’t change because Coke, McDonald’s and Wal-Marts changed them; it’s because they had access to the same technology. The percentage of food in China that comes from Western companies probably about four to 8 percent. The rest comes from their own production of commodities they take from us and reprocess and deal with.
So it’s – the answer is, yes, the technology, it came from us, often. But now they’re creating their own and it all was driven by internal companies adapting.
RAY SUAREZ: Michael Power, let’s talk a little bit about dairy. I had always heard as a young reporter that dairy products were not much consumed in China. And when I saw a long line outside a major American fast-food brand’s ice cream window out onto the street with happy Chinese people walking away with ice cream cones, I said to my translator, isn’t that kind of new? I mean, I thought that a lot of people would have gotten a stomachache in the old days. Have people gradually been eating more ice cream?
And she was a young person and hadn’t heard about this at all and had to ask older people to find out that, yeah, we didn’t used to drink milk or eat ice cream, but now we do. What’s going on there? Is that an adaptation? Was there really a higher predisposition to getting an upset stomach from dairy products that just goes away if you expose yourself to more of it? What – is it biological, cultural, social? What’s going on?
MICHAEL POWER: There is a relatively – in terms of adult mammals, there is very, very few of them that can actually properly digest milk because the lactose – lactose is a combined sugar, galactose and glucose linked together. And you need this lactase enzyme to be expressed to be able to break it up so that you can absorb it in your system. Obviously all baby mammals can produce that – at least all baby mammals in whose milk has lactose in it.
There are relatively few human populations that as adult continue to produce that lactase enzyme. In most adult humans the lactase enzyme basically starts going away, shutting down after age 3 or 4. And by age 6 or 7 it’s pretty much very minimal levels if at all.
I’m not aware that it can be induced particularly. It still doesn’t mean that milk couldn’t be drunk as long as it’s in small quantities. I don’t know whether they’re doing anything with their ice cream to break up the lactose in that. You certainly have plenty of dairy products in which the lactose has already been predigested. Yogurt is a classic example. It’s been used for thousands of years.
RAY SUAREZ: When I went to a grocery store, just to sort of check this out, the shelves were filled with reduced-lactose milk.
MICHAEL POWER: Well, then that’s basically what they’re doing is they’re using a technological change, a technological fix to be able to overcome the biological constraints.
BARRY POPKIN: But let me come in on that. There is a little bit of the low lactose. But for the first 15 years – the Chinese started exploding between around ’90 to the current decade in their milk consumption and their dairy consumption in general – it was looked at as a very chic commodity. But the levels of intake are really tiny.
RAY SUAREZ: So maybe it’s an urban thing then.
BARRY POPKIN: No, and even in the urban areas, these new lactose-reduced kind of items are brand new. As people have gone up in their level of intake they efface it. But populations can consume – I’m lactose deficient but I grew up in Wisconsin and I drink every day in the morning a glass of milk. And I can do it. But if I drink two glasses then I have a problem. There are dose levels. And the Chinese intake levels are so minimal today.
It looks like a lot in aggregate because there are a billion, 300 million Chinese, but it is so tiny yet. And these new products are reaching a tiny piece of that market. I have kind of consumption data from the stores of China, from like 3 million of them. It’s a tiny piece of the product line. It’s mainly regular dairy products, whole fat, that have more of the lactose but they’re not consuming very much.
RAY SUAREZ: Let’s close with –I’m sorry. Go ahead.
BARRY POPKIN: No, so it’s a – it’s looked – I should add two points. Chinese don’t breastfeed very long anymore. And the old products they gave children afterwards were really low energy and horrible products: starchy gruels, you know, like a little rice and water. And so shifting to even regular milk – not as good as shifting to formula, which is perfect for a child four or six months old, has been beneficial. And now they’re starting to consume more of the products that infants should consume. And stunting has gone way down as they have.
So these dairy products are really now being consumed not by infants, but by 1-year-olds to 7-year-olds generally. It’s looked at as being a healthy way to take a kid when they’re off formula forward. It would be okay except those same kids are getting fat because they’re having too much sugar and they’re not moving and they’re having a whole lot of other things in their diet. The milk is a teeny piece of the Chinese child’s diet.
RAY SUAREZ: To close, gentlemen, I want to get a short list of prescriptions from both of you. The numbers in China are daunting; the numbers in the United States are horrifying. The WHO is talking about “globesity” as one of the looming public health challenges of the 21st century. What does planet Earth with the manifestations of this problem being different in place to place to place, what’s the short list of things that people should be thinking about as we try to wrestle with a problem that nature didn’t prepare for us to deal with? Michael Powell?
MICHAEL POWELL: The first thing I would attack on this is truly on the exertion, energy-expenditure side of that. I mean, as Barry says, we don’t all want to go back to back-breaking work. I have no interest in living the incredibly hard life that our long-ago ancestors did. But, at the same time, making it much easier for people to walk, to use bicycles, to take stairs – you walk into any kind of major building in the United States, you can find the elevator instantly. You have to search to find the stairs. And the stairs often dump you out into inconvenient places that are difficult to get at.
And even during this interview, I mean, I know I’m sitting in a chair.I don’t know if Barry is or not, but we’re probably all sitting in chairs.We’re not standing as much as we do – most of our basic activities in work time have been put down into very, very low energy levels such that we are operating not much above basal metabolic rate.And that just lowers the bar for overeating.It’s extremely, very easy to overeat if your energy expenditure is less than one-and-a-half times your basal metabolic rate.
So, to me, the simplest thing is attacking the built environment to make it easier and safer for people to do simple exertion – walking, walking up stairs, standing, things like that.
RAY SUAREZ: Barry Popkin?
BARRY POPKIN: Water – drink water, not all of the sugary and caloric beverages we’re drinking. Really move to change the food supply in terms of the pricing and availability. Right now we cut the prices of animal foods and dairy products and sugars down to about 20 percent of what they were in real terms in 1950. And, in contrast, beans, fruits and vegetables’ prices have gone up. We need – we’re doing this in some countries. England is actually turning around its obesity. I’m involved on the beverage and some other sides. And they’re doing 20, 40 – they’re teaching kids who are in middle school to cook and drink – cook again. All kids, all schools are going to have kitchens. We need to go back and learn about food. We need to figure out ways to eat healthier and cut our calories at the same time.
RAY SUAREZ: That’s all the time we have for today’s forum. Thank you to our guests and thank you to all of you who sent in questions. We got so many; we never could have gotten to all of them. So thank you for participating and please know that we did try to get to a lot of the things you had to ask. And thanks also Barry Popkin. Good to talk to you.
BARRY POPKIN: A pleasure.
RAY SUAREZ: Michael Power, thanks for joining us.
MICHAEL POWER: Thank you