Welcome to Science Talk, the weekly podcast of Scientific American for the seven days starting August 22nd. I am Steve Mirsky. This week on the podcast:

Popkin: We have a world that is consuming more and more saturated fat and more and more hard fat meats and dairy products than we ever could have imagined 10 to 20 years ago.

Steve: That's Barry Popkin, author of the article "The World Is Fat," in the September issue of Scientific American. We'll hear from him this week, plus we'll test your knowledge about some recent science in the news. Barry Popkin is a professor of nutrition epidemiology at the University of North Carolina, Chapel Hill, where he directs the Interdisciplinary Center for Obesity. His research focuses on the changes in diet and activity in the U.S., China, Brazil, the Philippines and other countries and his article appears in the special September issue of Scientific American magazine, which is called feast and famine, all about diet, health and food. I called Popkin at his home in Chapel Hill.

Steve: Hi Professor Popkin. How are you today?

Popkin: Fantastic!

Steve: Tell me about this article and this subject, "the world is fat." Obviously it's fat if you walk around the U.S. but the world is now fat. There is an amazing fact right in the beginning of your article and that is, "there are not just more obese people in the world than there are hungry people in the world now, there are actually more obese people in developing countries than there are hungry people in developing countries." That really floored me.

Popkin: Yeah! It's what we really see in the developing world is in the last two decades, exponential change in a vast array of courses that have led people to move less and eat a lot more and the resultant increase in overweight and obesity is unprecedented.

Steve: When you say move less, you mean, actually walk less or bicycle less?

Popkin: Walk less, lift less, sit more.

Steve: And worldwide, the figures are astounding. You have a figure in the article, 1.3 billion overweight people versus only 800 million underweight people.

Popkin: Right! And the rate of increase of overweight is much higher than the rate of decrease; underweight is decreasing and overweight is increasing, so the figures are splitting and the estimate of 1.3 billion is at the lowest level. There are people that estimate it as double over underweight already. But the point is if you go to Egypt, you go to South Africa, you go to Mexico, you go to a large number of low- and middle-income countries, countries you think of as very poor like Egypt or countries you think of kind of lower-middle income like South Africa or Mexico, what you find are two thirds or three fourths of the men and women in the countries are overweight and obese.

Steve: You talk in the article about the situation in Mexico and how it has changed in less than one generation, it’s astounding.

Popkin: Right! We're essentially speaking of a country, Mexico, that in 1989 had a very small proportion of adults overweight and no children overweight and all of a sudden, you fast forward to 15 or 16 more years and you have 71 percent of the women and 65 percent of the men overweight, but worse than that in Mexico is during that same period they've reached a level of diabetes that equaled to what we had around 10 to 20 years ago in the U.S., and their increase in the rates of diabetes is so high—and all sorts of other complications that overweight and obese are associated with, you know, real heart disease as well as overweight and obesity pandemic in our country. That's only one of about 15 to 18 countries where we have more than half of the population overweight and obese in the world.

Steve: And is that because you basically take in a physiology that evolved under one set of conditions and have thrust it into this world of plenty?

Popkin: Essentially that, and let me give us an example—the question of beverages. If you think back for a million years up to 10 to 12 thousand years ago, all that we consumed as a race of hominins, and later Homo sapiens, is water, after maybe consuming for a year or two or three breast milk in infancy. So then you clearly, we didn't want to evolve, so that those who consume water would consume less food, so we essentially evolved a system of metabolism where the beverages we consume don't affect the food we consume. Then all of a sudden you get wine, beer and other alcoholic beverages which we had since around 10,000 B.C. and then in the last 150 to 200 years, all the new beverages—the carbonated beverages, the pasteurized milk and so forth, and the fruit juices that are shipped in box[es], then quick crated, and we see a new generation. But even up to 1950 we consumed very few calories from beverages and in the last 60 years, we've gone from consuming almost no calories from beverages to a fifth of our caloric intake in the U.S., and about the same in Mexico and about the same in a dozen other countries—in some less and some more—but the point is, all of those calories we consume, but it doesn’t affect the food that we take in. So if you consume water, you don't gain weight; if you consume Coke or Pepsi, you gain weight, it's that simple.

Steve: And you also identify in the article a couple of other major developments that have contributed to the worldwide obesity epidemic.

Popkin: Right and most of those are really on the food side. Because it's a lot harder to expend energy to make up if we drink a Coke or eat a hamburger. So the second, the big trends in the world are one that is tweaking of our diet, not only beverages in particular, but also food. The second is in the area of edible oil and vegetable oil. This is something if you live in the U.S. or U.K. or Europe, maybe starting in the 50s and 60s, you started getting margarine and vegetable oils and so forth and but in the lower- and middle-income world all these liquid oils and these hydrogenated solid oils, we think of Crisco. Crisco. If you are in India, you think of vanaspati in other countries but they are hard oil and the liquid ones. All of these essentially came into the developing world very cheaply in the 70s and 80s and they exploded in consumption in the 80s in these countries, so that in a country like China, people consume 300 to 400 calories a day right now from vegetable oil. That's a lot of calories from just pure fat. And it adds value to them. It makes food taste better; it makes things smoother on the tongue. There are a variety of reasons why fat is nice, so that's trend number two. The third trend is what I call animal foods, animal-source foods—that's dairy products, milk and cheese, that's yogurt, that's eggs, fish, poultry, beef and pork mainly and in one country. it may be In India it may be diary, in China it may be pork and beef and in another part of the developing world it may be only beef, but whatever it is, it is really increasing. Most of the increase in the world is coming from consumption of these products in [the] developing world and what's important is the world price of beef in terms of a 100 kilogram—40 years ago was around $500, in real terms. It doesn't really matter what the terms are, but it went down to a fifth of that today or fourth of that. So, the world prices have cut so much for these animal foods and a number of other products based on subsidies from the West, based on just major pushes to promote consumption of these items so that we have a world that is consuming more and more saturated fat and more and more hard fat meats and dairy products than we ever could have imagined 10 or 20 years ago.

Steve: It strikes me that what you have now then is a huge public relations problem because how can you tell these people who have risen out of poverty to the degree where they can now afford these foods that are associated with affluence? How can you tell them, "go back to your previous diet of vegetables and whole grains, because it was actually healthier for you," when it just feels like you are being paternalistic with that kind of message?

Popkin: Right! That's one way of looking at it. Clearly the diet of 25 years ago or 20 years ago—I have lived in most continents of the world—when I lived in villages in each of the region[s], the diet was missing something. So it wasn't as healthful as it could have been and that's why we had hungry and malnourished, particularly children, but also adults and there are still pockets of hunger in many many countries throughout the world, certainly in south Asia and sub-Saharan Africa, but what happened is that the same people who were hungry and malnourished 20 years ago are today overweight and obese. So, it is the same human being that you are telling him that which is difficult, but it is the same politician, it's the politician who has been fighting against hunger. You all of a sudden have to say, "no, we are not concerned about poverty and hunger anymore in Mexico or Chile or China, now we have to be concerned with obesity and heart disease and we are losing people from that and it's going to destroy our health system in another 10 years’" And some countries are really willing to take it on. So, Mexico is an example where the minister of health wants to tax items, wants to take really aggressive stands; in the cabinet many people in the government are behind that person in the congress. On the other hand, I work in a country like China, where it is very hard yet for the political system to truly to take the gutsy changes they need to deal with something that's going to eat up their economy.

Steve: You know we've seen in this country that if you do raise taxes on cigarettes and alcohol, you do get a public health effect out of that, but you are never going to be able to raise taxes on soft drinks in this country for an alleged public health effect, I think.

Popkin: I am not so sure. I talked to my state legislators about issues like this. They tell me what they are doing today in a state that's quasi-liberal, quasi-conservative like North Carolina very next, they couldn't have conceded doing legislatively four years ago and they are saying the climate is changing so rapidly. People are so concerned now that in the U.S. and Australia and countries throughout the world, we are getting teenagers and younger children with adult diabetes, a condition that we didn't see until you are age 40, 25 years ago. All of a sudden, we are getting eight- to 20-year-olds with these conditions. That's scaring a lot of parents and moving public opinion far over. In fact, I think in some cases, because of the funding in the way Congress is handled with business and so forth, Congress is often behind the ball compared to the states right now, and every state in the country has had legislation in the last year, [and] in my country, and I've got a few countries that really want to take this on very seriously and will. The U.S. may lag, but when other countries have success from this and when we see our medical care cost going over 20 to 25 percent above budget, you can bet we're going to start to take more action.

Steve: Other than raising taxes on high-calorie foods to try to change people's habits, what are some other possible solutions to this worldwide problem?

Popkin: Well I wouldn't do. First up, I would check high-calorie beverages. It's clear that we know if we consume a beverage, you check that calories. If you consume a food, it['s] sort of a trade-off there. I would start to work on getting rid of advertising and promotion of all the sugary fatty foods that we have, starting off with children, but do like we did with in the end, really control that. I would begin to start to think of issues related to portion sizing and portion-size pricing at least and there is a number of trends and it depends on the country. In China, I am working with them on edible oil taxing and changing certain subsidies. In our country, in the U.S. and in most of the higher-income world, we subsidize the production of animal-source food, and we don't give money in the same amount to fruits and vegetables. I would shift it around. I would start to remove slowly the subsidies on one and start to really ratchet up the amount of money we are funding to allow us to have cheaper fresh fruits and vegetables and canned and frozen fruits and vegetables. We can change the pricing system a lot easier than we can change other things and that's what works for tobacco, much more than just educating people. We need to do that, too, and that's happened. People are starting to be concerned. Parents are starting to be concerned. But only middle and upper classes across the world; still, most of the overweight and obese in the world is in the low and middle-income population. It's not a problem of the rich. So we need to find ways that will benefit the low- and middle-income group[s], who may not have access to knowledge or have the education to absorb it in the same way.

Steve: So what do you say—and you actually addressed it in the very last thing that you just said—but theoretically, what do you say to a free market advocate, who says, "Well, you know, the information is out there are then people have a choice, and if they want to eat these foods, why should you do something to try to control the markets to stop them?"

Popkin: Well, the first thing's answer is, we've been subsidizing for a 115 years. The production of sugar to make it very cheap, we've been doing the same for oils and we've been doing the same for animal-source foods. So, we now have to turn around to the real price of that and find ways to have people pay the true cost of what they are consuming and part of the cost are environmental, part of them are in health terms and so that's the first answer; it is that, there is no such thing as the free market, we are subsidizing all these products that we said we are not touching. The second issue is there are huge social and economic cause[s] associated with obesity, just like the work with tobacco and lack of seatbelt use and other things. People are being killed and health care cost has skyrocketed. So the health care costs that are going to destroy the U.S. economy and the economies of many countries, unless we find the way to come to grips with them.

Steve: The article is called, "The World Is Fat," in the September Scientific American. Dr. Popkin, thank you very much. I appreciate it.

Popkin: My pleasure.

Steve: The entire September issue of Scientific American is also available in digital form on our Web site, www.SciAm.com. Barry Popkin is also the chair of the Nutrition Transition Committee of the International Union for the Nutrition Sciences. For more on his research, go to www.nutrans.org. Popkin's book, also called The World Is Fat, comes out in April 2008. We'll be right back.

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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.

[AUGUST 30 EDITS END HERE]

Story number 1: A viral infection might be a factor in some cases of obesity.

Story number 2: You might have been able to outrun a T. rex. Computer analysis indicates that T. rex probably reached a top speed of only about nine miles per hour.

Story number 3: A CNBC anchor warned that lead-free toys and safe food would drive up prices.

And story number 4: Cats remember some things better through movement than through sight.

Time is up

Story number 1 is true. Adenovirus 36 has been found to encourage the transformation of adult stem cells in fatty tissue into fat cells as discussed on the daily Scientific American podcast 60-Second Science on August 20th. Although the obesity epidemic is no doubt more a result of the caloric factors, professor Popkin just discussed.

Story number 4 is true. Research with house cats at the University of Alberta found if they raised their front legs to move over an object and are then stopped by, for example, a bowl of food, they will raise their back legs when they continue moving even if the object that they had a step over with their front legs was removed up to 10 minutes earlier. If they only see the object without having to step over with the front legs, their memory of it fades after a few seconds after it is removed.

And Story number 3 is true. On August 10th, CNBC's Erin Burnett actually said:

Burnett: If China were to revalue its currency, or China is to start making say toys that don't have lead in them or food that isn’'t poisonous, their cost of production are going to go up and that means prices at Wal-Mart here in the United States are going to go up, too.

Steve: That laughter you heard was the audience of The Daily Show, which played that clip from CNBC. Breathtaking isn't it? After receiving some criticism, Burnett attempted to clarify her comments and she said, "Nobody wants children to play with toys that are not safe, nobody wants that, I don't want that, you don't want that, but safety and quality come with a price."

Ms. Burnett apparently studied economics at the Milo Minderbinder School of Business. In an admittedly nonscientific poll that I took over the last few days, 100 percent of those surveyed were willing to pay more for food that was not poisoned.

All of which means that story number 2 about the top speed for T. rex being nine miles per hour is TOTALL.......Y BOGUS. Because a computer modeling study in the latest issue of The Proceedings of the Royal Society B found that T. rex probably topped out at about 18 miles per hour, you would've been a lunch. The fastest dinosaur modeled was a chicken-sized carnivore called comsognathus, which looks like it could hit 40 miles per hour. I was once in the Everglades with a friend who told me that an alligator could run faster than I could. I said to my friend, "I don’t have to run faster than an alligator, I would only have to run faster than you."

Well that's it for this edition of the weekly Scientific American podcast. You can write to us at podcast@SciAm.com, check out news articles at our Web site, www.SciAm.com. The daily SciAm podcast 60-Second Science is at the Web site and at iTunes. And I am a guest on the current episode of The Skeptics Guide to the Universe podcast, there at iTunes and at www.theskepticsguide.org. For Science Talk, the weekly podcast of Scientific American, I am Steve Mirsky. Thanks for clicking on us.