Marion Nestle on the Gluten-Free Fad, Big Soda Ban, and Salt

Henry R. Black, MD; Marion Nestle, PhD, MPH


July 24, 2014

This feature requires the newest version of Flash. You can download it here.

Gluten-Free: Mania or Medical Necessity?

Henry R. Black, MD: Hi. I'm Dr. Henry Black, Adjunct Professor of Medicine at the New York University (NYU) Langone School of Medicine. I am joined by Marion Nestle, Professor of Nutrition, Food Studies, and Public Health, and Professor of Sociology, at NYU.

I want to talk about a subject that has increased in interest of late: the question of gluten. I read your quote in the New York Times.[1] The gluten-free diet seems to me to be a fad, but maybe it's more than that. What do you think?

Marion Nestle, PhD, MPH: Two things are going on with gluten. One is that real gluten intolerance (celiac disease) is much easier to diagnose now than it was 10 or 15 years ago. As far as I know, the percentage of people who have real celiac disease hasn't changed. It's roughly 1 of 133 people,[2] which doesn't sound like much, except we have a lot of people in this country. Millions of people are not able to digest the proteins in wheat and become very sick if they do.

On the other hand, many people think that they have gluten intolerance and they don't want to bother to go through the diagnostic procedure. I don't blame them. It's not a very nice procedure. You have to ingest gluten to mess up your digestive tract, and then have an intestinal biopsy. That is something I wouldn't want to endure if I could avoid it. So many people are eliminating gluten and deciding that they feel a lot better when they don't eat fods containing wheat, and they think that their children behave better. They consider themselves to be gluten-intolerant. Whether they really are gluten-intolerant, we don't know, but they feel better when they don't eat wheat.

Dr. Black: How much more expensive are so-called "gluten-free" products, and how do they taste compared with foods that have gluten in them?

Dr. Nestle: It depends on what they are. Many gluten-free products never had gluten in them in the first place. In that sense, it's very much like what the "no cholesterol" claims used to be for foods that never had cholesterol in the first place. Other products are deliberately created for people who are gluten-intolerant. If you are gluten-intolerant, such foods are a blessing. If you are not gluten-intolerant but you think you are, you may like them or not, but it seems like a lot of trouble to go through if you don't have to. The products don't taste very good, but I'm not gluten-intolerant so it's hard to say.

Dr. Black: I'm quite sure that this is the case, but we will never do an appropriate clinical trial to show whether eliminating gluten really makes a difference or whether it's the placebo effect that we see often enough. It's unfortunate, but if people don't mind and if there is no additional cost associated with the products and they taste fine, then it's probably not a problem.

Dr. Nestle: The products are more expensive, but wheat is not an essential nutrient. You can have a perfectly healthy diet without eating wheat or wheat products. For many people, wheat products are the source of very large numbers of calories. What the Department of Agriculture charmingly calls "grain-based desserts" are the leading source of calories in American diets. When people cut out those foods, they are cutting down on their calories, and that may have benefits for their weight.

Dr. Black: That is certainly positive. Are these so-called "empty calories"?

Dr. Nestle: Some of them are more empty than others. What nutritionists mean by "empty calories" are foods that provide calories and no additional nutrients. I can't think of anything besides sugar that does that. Grain-based desserts and other grains, and bread and other foods that contain a lot of wheat depending on how refined they are, may have all of the nutritional value of the original grain, depending on how much processing has been done. In general, what is in most American diets is heavily processed. The calories aren't empty, but they are emptier than they would be if you were eating whole grains.

Goodbye to Big Gulp

Dr. Black: This brings us to another issue of late in New York City, which is the question of taxing sugary drinks. What do you think about the value of that?

Dr. Nestle: An enormous amount of research has been done on the effects of taxation on consumption. The general conclusion is that a tax of 20% on foods that you don't want people to eat would reduce consumption. Soft drinks are the logical target for such approaches because they contain sugar, water, and flavorings, and nothing else. They have calories but no nutrients. They are the prototypical empty-calorie product. An enormous amount of evidence now shows that people who drink a lot of soda are heavier and have poorer diets than people who don't drink soda. In fact, the number-one weight loss strategy for many people is to stop drinking sugary drinks and the weight just falls off. I hear this over and over.

For cities that are paying healthcare costs, for people who have type 2 diabetes, which is closely related to obesity, trying to help people reduce their risk for obesity seems like a good idea. That's why tax strategies are considered. They also generate revenue. To the extent that those revenues are applied to preventive healthcare or to some kind of social purpose, many people don't think they are so terrible.

Dr. Black: As a preventive cardiologist, I would like all the help I can get to avoid using pharmaceuticals if possible. It's often very difficult to get people to exercise more and lose weight. People in behavioral medicine have to help us because we are not trained as physicians to do that very well.

Dr. Nestle: It's very difficult to lose weight if you live in the kind of food environment that most Americans live in now, where food is offered everywhere in large quantities at relatively low prices. Everybody else around you is eating a lot and it seems normal to eat a lot. It's very difficult in that situation to exercise personal responsibility and not eat so much. That is why public health experts are looking at what they call "environmental strategies" to change the food environment into one that makes the healthier choice the easier choice. People can always order the things that they want that aren't good for them, but they would have to take action to do that.

That is why Bloomberg's soda cap idea was so interesting. It's not quite over yet, but I hope that the Supreme Court lets the city give it a try. It would reduce the maximum size of a soft drink that you could buy within city limits. You can always order more if you want to, but research shows that people don't do that. People consume what they are given. If it comes in a container, they finish it regardless of the size of the container. The idea of having smaller containers makes a lot of sense, and it would be very interesting to try it.

Dr. Black: People who sell sodas might say, "If I can't sell the 32-ounce beverage, I will sell the 16-ounce beverage and give the other 16 ounces away for free."

Dr. Nestle: I don't think most sellers will do that. If people want 2 drinks instead of a single 32-ounce drink, they can ask for another drink. Most people won't. That's why the strategies about Happy Meals at McDonald's and other kinds of fast food places are so interesting. You want the default, the item that you get without having to ask for it, to be healthy for kids. Parents can always order sodas or other unhealthy foods for their kids if they want to, but chances are that most won't. Most will just eat what is presented to them.

Lower the Salt, Gradually

Dr. Black: I agree. The other nutritional concern that is very important to me as a hypertension specialist is the question of salt and sodium intake. We have had some interesting Medscape discussion about this. My opinion is that 2300 mg of sodium daily is the appropriate level, and that a 1500-mg sodium limit is very difficult to do. In the United Kingdom, with Graham MacGregor,[3] they have gradually reduced the salt in processed foods and it is already beginning to have an impact on the number of strokes and heart attacks in those communities. We ought to follow their lead on that.

Dr. Nestle: I agree, but the food industry absolutely opposes it. In England, the food industry gradually reduced salt voluntarily, but we don't do voluntary in the United States because nobody wants to go first. The food industry has said that they cannot sell products with lower salt. This is another environmental issue. It is very difficult for people to consume a low-salt diet in the United States if they eat out or buy processed foods. To consume a truly low-salt diet, you have to do all of your own cooking and control your food intake very carefully. Most people don't do that. Everybody in America eats out at least sometime during the week, and the food is loaded with salt. The reason that it is loaded with salt is that the people who are preparing the food eat a lot of salt, and it takes a lot of salt to make the food taste good to them. When people go on lower-salt diets, food starts tasting very salty to them.

Dr. Black: Research done by Dr. Henkin back in the 1970s showed that if you gradually reduce the amount of salt or sodium in the diet, that within 30 days foods that you used to think were fine taste too salty. That's part of the reason it has worked in the United Kingdom. The amount of sodium in processed food has been gradually, and not drastically, reduced. It is certainly beginning to be reflected in their data on strokes and heart attacks. I wish we could do the same here.

Dr. Nestle: I know that many people are working on it.

Making Healthy Diets a Priority

Dr. Black: We all have to work on it. In the nutrition, medical, and public health arenas, we have to make this a real priority. I am a little encouraged by the thought that obesity rates are leveling off and maybe even going down a bit in young children,[4] and that is probably because it has been a public health priority for politicians. How can you be opposed to less diabetes and obesity? It's pretty difficult to do. It's hard to fight the food industry. They are very conservative. They don't want to be first, but if they could all do it and if they could promote lower salt -- not necessarily low salt -- that would make a difference.

Dr. Nestle: It's not just the processed food industry. It's also restaurants. Restaurants are a particularly difficult problem unless the government regulates salt (which I think would be terrific); the US Food and Drug Administration (FDA) has been working on standards for salt intake for packaged foods that have food labels on them. That will help, but everybody has to do this across the board and do it slowly and gradually over some period of time. Then everybody would start tasting the real taste of food.

Dr. Black: Why do you think the campaign against trans fats was so successful?

Dr. Nestle: The campaign against trans fats was a no-brainer. They are artificial. They don't occur in nature. There are lots of substitutes. They have no taste value. You can easily substitute another oil for partially hydrogenated oils and it doesn't change the taste. You can substitute other kinds of fats for the texture. Opposition to that, especially in New York City where the City Department of Health banned trans fats, didn't come from people who were opposed to the idea on any kind of principle. It came from people who didn't know the difference between foods containing trans fats and those that didn't. Once they found out that other kinds of oils could be used, they didn't care. It didn't even cost more. It was very easy to do. I don't understand why the food industry is fighting the last remaining trans fat requirement. The FDA wants to remove trans fats from substances generally recognized as safe. The food industry is fighting that as hard as it can, and I don't understand why.

Dr. Black: We have learned from what happened with taxing cigarettes and tobacco products that the increased tax did reduce cigarette consumption, especially in younger people who were watching their budgets. Maybe improving the labeling of food and having some warnings on the labels about sodium, which we don't have, would help. People are used to looking at how much cholesterol and saturated fats are in foods, but they are not as used to looking at the amount of sodium, because it's confusing. Even the difference between calling it salt or sodium is confusing. We have to be very careful as we put that together.

Do you have any last thoughts about how we in medicine and you in public health and nutrition can work together to get this done?

Dr. Nestle: We have to work together with government to try to get policies in place that are going to make it easier for everybody to achieve healthier diets.

Dr. Black: I agree completely. I want to thank you for your time today.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.