The human digestive tract has about the same number of neurons as the spinal column. What are they there for?

The final word isn't in yet, but Michael Pollan thinks their existence suggests that digestion may be more than the rather mundane process of breaking down food into chemicals. And, keeping those numerous digestive neurons in mind, Pollan's new book In Defense of Food: An Eater's Manifesto entreaties us to follow our knowledgeable guts when it comes to figuring out what to eat.

Nutrition science and the food industry have been changing their minds about what Americans should eat for years. Low fat, no fat, low carb, high protein. In In Defense of Food, Pollan argues that all of these fixations amount to a uniquely American disease: orthorexia -- an unhealthy obsession with eating. And as statistics on diabetes and obesity can attest, obsessing doesn't seem to be getting us anywhere. Pollan takes the reader on a journey through the science of food and reveals how it is that we've ignored our guts and followed the ever-changing tune of food science. At once a scathing indictment of the food industry, and a call for a return to real food, Pollan's latest book reveals how Americans have been dangerously misled into adopting "low fat" as a fundamental food mantra, and how most of the products on our supermarket shelves should be called "imitation."

Pollan recently sat down with AlterNet to explain why cooking from scratch has become a subversive act, and to tell us things our guts probably already knew.


Onnesha Roychoudhuri: At the very beginning of the book, you indict your own field -- journalism. You write, "The story of how the most basic questions about what to eat ever got so complicated reveals a great deal about the institutional imperatives of the food industry, nutrition science, and -- ahem -- journalism ..."

Michael Pollan: The way journalists report on science contributes to the confusion about nutrition. We over-report the latest findings. Science is this process where hypotheses are advanced, and then they get knocked down. But you lose track of that when they run the big story on page 1: "Study of Low-Fat Diets Finds They Don't Really Work." That makes it sound like a consensus has formed. You look more closely and you realize, well, that's not really what that proved. It really proved that it's very hard to get people to go on a low-fat diet. The people in that study didn't really reduce their fat intake that much. We've tended to amplify a very uncertain science.

The larger issue is that the very nature of journalism and the nature of food don't make a good fit. Food is a really old story. The foods that we do best on are the ones we evolved eating over many thousands of years. But journalism needs a new story every week, and so we tend to play up novelty and surprise. The classic methods are to eat more fruits and vegetables. How are you going to interest an editor in that story? But in fact, that is the story. Nutritionists haven't changed their points of view nearly as much as you would gather from reading the journalism about them.

On the other hand, there is a very good fit between journalism and the food industry, which needs lots of change. The food industry needs to know that the blueberry is the food of the moment and that there's very exciting research showing that it's a "superfood" so they can put blueberries in all their products. That suits both journalism, which needs a new story every week, and the food industry, which puts out 15,000 new products every year.

OR: This constant influx of food products seems to be the result, in part, of this rise in the prominence of focusing on "nutrients." Can you explain how we became fixated on nutrients?

MP: In 1977, Sen. McGovern, who had convened this select committee on nutrition, was looking at why there was so much heart disease post-WWII. The thinking then was that people were eating too much animal protein. So his initial recommendation, quite plain-spoken, was to eat less red meat. Turns out the industry would not let the government say "eat less" of any particular food, so there was a firestorm of criticism. He was forced to compromise on that language. He changed it in a way that would prove quite fateful in many ways. He changed "eat less red meat" to "choose meats that will reduce your saturated fat intake."

There are a couple noteworthy things about that. One is it's a lot less clear and a lot of people aren't going to understand it, which certainly suits the food industry. The other is, it's affirmative. It's saying "choose meats." In other words, eat more of something that will have less of the bad nutrient -- saturated fat. We're no longer talking about eating more or less of a particular food; we're saying eat more or less of a particular nutrient. That became the acceptable way for everyone to talk about food. It didn't offend the food industry because they could always change their products to have more of the good nutrient, less of the bad. And I think it was very confusing to people: Foods are not merely the sum of their nutrient parts.

OR: Can you explain how this focus on nutrients impacts medical studies as well?

MP: The focus on single nutrients, which is to say single variables, is necessary to science. This is part of the nature of reductive science and it's part of its power. But, it is not the way that the rest of us need to look at food. When a scientist learns from the epidemiology that diets high in vegetables, fruit and whole grains seems to confer some protection against cancer, the scientist needs to figure out what in that diet is responsible. So, he or she immediately is going to look for the "x" factor. Is it beta carotene, is it vitamin E? Then they break down the food into its component parts and study them all individually to see if they can find an effect.

As it turns out it's been very hard to do that and, often, when we isolate these nutrients, they don't seem to work the way they do in whole foods. Maybe they'll figure out what's going on. But the point is, for us eaters, it doesn't matter. All we need to know is that eating lots of fruits, vegetables and whole grains confers some protection against cancer. Who cares what the mechanism is. They want the mechanism because they're curious and it's the nature of science to satisfy curiosity, and the industry wants to know the mechanism because then they can make a supplement or they can fortify foods with that magic ingredient.

But, for now, stick with the foods. We know it works.

I'm not a Luddite; I'm not anti-science. I'm fascinated by nutritional science. But I've also acquired a healthy skepticism about how much and how little they know. It has only been around for about 175 years. Its history is of one overlooked nutrient after another. As I see it, nutrition science is kind of where surgery was in the year 1650, which is to say very interesting and promising, but do you really want to get on the table yet?

OR: You describe nutrition science as being, in some respects, "parking lot science." Can you explain this?

MP: You measure what you can see, and you inevitably decide that what you can see is what matters. Cholesterol is a classic example. It's the first factor related to heart disease that we could measure. So, the science got obsessed with cholesterol, and cholesterol became the cause of heart disease, and dietary cholesterol was what you had to eliminate. This is parking lot science. It's based on the parable of a man who loses his key in a parking lot at night. He spends all his time looking for it under the lights even though he knows that's not where he lost it, because that's where he can see best.

We have a science that often proceeds that way. But then new factors emerge. Now we know about triglycerides and C-reactive protein and homocysteine, and we're studying those as well. Scientists understand this about themselves better than the journalists who write about science do. They understand the limitations. They've come out and made recommendations that perhaps were less than helpful, such as get off animal fats and get onto margarine and trans fats, but on the other hand, they understand that what they're doing is still very provisional. It's the rest of us that have taken what are very partial, imperfect findings and tried to organize a food supply around them, such as when we took all the fat out of the foods.

OR: Everyone has heard about the low-fat diet. In the book, you talk about how little evidence there is that this diet -- bolstered by the lipid hypothesis -- is the magic bullet.

MP: I was very surprised when I started delving into that. The big message from nutrition science and public health since the 1970s has been that the great dietary evil is fat -- saturated fat in particular. In the years since, this hypothesis has gradually melted away. There are still people who think that saturated fats are a problem because they do raise bad cholesterol, but they also raise good cholesterol. But there are very few people left who think that dietary cholesterol is a problem. There is a link between saturated fat and cholesterol in the blood. There is a link between cholesterol in the blood and heart disease. But the proof that saturated fat leads to heart disease in a causal way is very tenuous. In one review of the literature I read, only two studies suggested that, and a great many more failed to find that link. Yet the public is still operating on this basis that we shouldn't be eating cholesterol.

In fact, when the government decided to tell people to stop eating fat or cut down on saturated fat, the science was very thin then. But the net result of that public health campaign was to essentially get people off of saturated fat or try to get them onto trans fats, and we've since learned that that was really bad advice because the link between trans fats and heart disease is the strongest link we have of any fat to heart disease. They told us butter is evil and margarine is good, and it turned out to be the opposite.

You still see all these no cholesterol products and no saturated fat, and the American Heart Association is still bestowing its heart-healthy seal of approval to any products that get rid of fat no matter how many carbohydrates they contain. The science has moved on. The science now is much more curious about things like inflammation as a cause of heart disease and the fact that refined carbohydrates appear to increase inflammation and metabolic syndrome. These assaults on the insulin metabolism from refined carbohydrates are perhaps a culprit.

I was surprised at how few scientists would defend this lipid hypothesis as the great answer to the questions of diet and health. Nevertheless, they move on because scientists don't stop and come out and say, "You know, we were really all wrong about that." They just keep moving forward. That's the way science should work. But there should be a big disclaimer saying, "Wait till we figure this all out before you change the way you eat and before the government issues proclamations."

Read the full article

Copyright (c) michaelpollan.com