PSYC 123: The Psychology, Biology and Politics of Food

Lecture 4

 - Biology, Nutrition and Health II: What Helps Us and Hurts Us


Professor Brownell reviews the challenges inherent in research assessing the link between diet and health, and the challenges of basing a diet upon different dietary recommendations. Fundamental information on nutrition is presented, as well as how our current diet suggests we are eating too much or too little of different classes of sugars and fats.

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The Psychology, Biology and Politics of Food

PSYC 123 - Lecture 4 - Biology, Nutrition and Health II: What Helps Us and Hurts Us

Chapter 1. Challenges to Dietary Assessment [00:00:00]

Professor Kelly Brownell: All right guys, welcome back after the weekend, I hope you all had a lovely weekend and a nice time. I hope this class isn’t changing your sleeping habits too much, but I’m delighted to have you here.

Today we’re going to talk about food and health and how food links to health. But before we’d do that I’d like to just have a quick discussion about your experience with the Daily Plate. By the way, when we turn in concept sheets each week you’ll have the option of turning them in either on Monday or on the Wednesday of that week, whenever you choose to do it is fine. The teaching fellows right after the class will put up on the stage sheets of paper that are broken down by parts of the alphabet, so make sure you have your names on the concept sheet because you’re getting grades for these, and then just put them up in the relevant part of the alphabet that you see on the stage. As I mentioned, we’ll rotate the teaching fellows through different parts of the alphabet, so every teaching fellow will have equal opportunity to grade work from each person in the class.

On — this week because the first concept sheet is different than the rest — you were using the Daily Plate Dietary Assessment — we’ll send out this week a sample concept sheet. Somebody told me, by the way, that the sample concept sheet that we have listed on the website couldn’t be downloaded, so we’ll fix that, but we’ll also send you out by email a sample concept sheet, along with guidelines for how to prepare them. We tolerate a lot of variability in the concept sheets because this is your opportunity to be creative and to think about whatever you’re reading or hearing the lecture that week, so there’s no specific format to follow. You can choose whatever topic you want to write about. The key thing is not just to feed back to us what you’ve read or what you’ve heard in the lecture, but we want some interpretation of it or some analysis of it, or your reaction to what you’re hearing in the class linked with something that might be going on in the world. We’ll grade them leniently in the beginning and so everybody will get some feedback about how they’re doing on those.

We’ll also, when we grade the concept sheets, we’ll give them number grades and we’ll just do one, two, or three. And three will mean you did a really good job that will be top grade. Two will mean it’s good but you could have done a little better, and one would mean you need to shape it up. I’m expecting that after we get going a week or two into the class, we just won’t see any one’s at all and people will get good grades on those.

What were you experiences with the daily plate? How many people found it difficult to do? Okay, how many people feel that it represented a really accurate picture of what you’re eating in terms of the amount and the types of food and everything? Okay, well maybe a dozen people at the most. Okay. What are some of the things that you thought dampened its accuracy and its validity? Go ahead.

Student: [inaudible]

Professor Kelly Brownell: Okay, different calorie amounts listed for the same types of foods. What are some of the other things you guys found that you thought might diminish its accuracy? Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, so once you reach 2 000 calories you don’t want to put anything else in. Now by the way, there are a couple of interesting things embedded in your comment. One is that 2 000 calories is the average for the typical person, but of course, people have greatly differing calorie needs. Men will need more calories than women, people who are very active will need more then people who are less active, etc. Plus there are some natural metabolic variability and I’ll describe that in a subsequent lecture. That’s right. That’s an example, as we talked about in the last class, of the act of keeping records influencing the accuracy of the records, because you’re prone to do things differently then what your typical eating might be because you’re keeping the records. Other things that you think might make it difficult to be accurate with those? What about estimating the amount? Go ahead.

Student: [inaudible]

Professor Kelly Brownell: Okay, right, so if you’re actually making food and you’re creating some of a recipe then it’s very difficult to know exactly the portions that go in when you eat the final food product that comes from it, so that’s right. How many of you — go ahead.

Student: [inaudible]

Professor Kelly Brownell: Okay, so there was some irony built into it because the program itself was weighted so heavily toward processed packaged foods and eating out. And that’s right, that’s exactly what reflects the typical American eating pattern, since more then half of meals now are eaten outside the home. So from that point of view it’s probably good, but from the point of view of wanting to eat more foods that you prepare yourself and not eat process, and package, and things like that it may not be so good.

Okay, so you guys have identified some of the key issues that make dietary assessment so difficult. There are really two purposes in us doing this: one was so you can get a fix on your own eating, and second you can see the challenges that are involved in assessing what people eat when you start doing studies linking diet to health. A lot of what we know ultimately about fat in the diet and risk for heart disease, risks for cancer from certain sort of diets, the protective effect of certain diets comes from studies that rely on just the kind of assessment that you guys just did. Now, we probably could have improved the accuracy if we had spent individual time with each of you and said, well now here’s a serving of this and that’s — here’s a serving of that. You could have gotten a little training that might have helped you be more accurate. But you can imagine the inability to do that in a big population study with thousands and thousands of subjects, so we have to rely on data like this. Were you guys surprised by anything that you found when you actually printed out the final details? What kind of surprises did you find when you did this?

Student: [inaudible]

Professor Kelly Brownell: Okay, so way over the protein limit even though the intake of meat isn’t so high. Okay, so that was one surprise. Other surprises people experienced with this? Did — were people surprised by the number of calories that you total up at the end of the day? Or were you pretty familiar with how calories add up? Okay, so you guys were on top of that. Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, so you had less calories than you thought you did. Okay, so you could see difficulties in estimating on both sides of the norm. Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, so 2500 calories one day; 1400 another. So you can see the kind of patterns, the variability from day to day that people get. Now you could imagine, since you did three days, you could imagine if we were — you were part of a big study and we came in and we assessed you — what kind of a difference we’d get depending on which of those two days we evaluated you and so that’s why you — the more days you collect the more likely you are to get representative intake from an individual, but when you do one day, which is pretty common in these studies, then you’re — it’s pretty much a crap shoot and you hope that you might, if we estimate — we evaluate you on one day and your high on that day, somebody else we evaluate and they’re low on that day and it kind of evens itself out across a lot of people. But there’s still a lot of error introduced. Did I see another hand over here? Okay, yes?

Student: [inaudible]

Professor Kelly Brownell: Okay. Okay, so no surprises on how many calories were coming in meals, but in snacks yes, because there’s a lot of stuff that you kind of don’t consider when you’re just noshing here and there and it kind of adds up. Okay, yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, how little plain water was actually consumed. We’re going to talk in this class a lot about beverages, and it’s interesting how the population consumption of calories through beverages has gone way up. People used to consume a relatively small percentage of their calories from beverages, but for a variety of reasons including marketing, the percentage of calories from other beverages other than things like milk has gone way up. Okay, it’s interesting to hear your experiences with these and we look forward to seeing the concept sheets and your reactions to them, so we hope that was a good experience for you. As I said, you’ll get information on doing the other concept sheets later.

Chapter 2. Carbohydrates: Sugars, Starches and Sources [00:09:01]

All right, I’d like to continue what we started discussing last week, which is some fundamental information on nutrition. Today we’re going to talk about the two big ones that people are usually concerned with: carbohydrates and fat. Let’s start with carbohydrates. Sugars, in other words. The word “carbohydrate,” as you might imagine, if you ever thought to break it down means the combination of carbon and water. Carbohydrates come in the form of sugars and starches. We’re interested in both of those for reasons of health. They’re used by the body for pretty immediate energy where fat is a little bit more long-term energy, and there are many types of sugars — and these are things that you’ve heard — glucose and sucrose being the most common things that you can consume in ordinary foods, and then lactose of course, from milk. You’ll see other slides that break these down.

Sugars come from many sources. Some people understand and some people don’t think about it so much. Usually when people drink milk they’re not thinking that they’re consuming sugar but they are. Then of course there’s sugar itself, and then there’s other kinds of sugar in things like fruit. Then of course there’s the sugar you see in all the processed foods that you might think of. There are three classes of sugar: monosaccharides, disaccharides, and polysaccharides. It’s not so important that you know which sugars fall under each of these categories, but it is important to know that there are different categories of sugars.

Under the monosaccharides, glucose, fructose and galactose are the sugars. Disaccharides, where you have several sugars paired together, are maltose, sucrose, and lactose; and then you can see to the right of the sugars themselves which things are paired in this case. Then the polysaccharides are the complex carbohydrates, and that’s starch, glycogen, and cellulose. Now, again, we go through these faster then you can write, and as you all know, the lecture notes are posted on the website, so if you need to go back and refresh your memory on these things you can. Just as a note, I cued you about the level of detail I’m expecting you to acquire from class and from the readings, and I’m not so interested that you memorize those particular sugars and which category they fall under, but it is interesting to know that there are different types of sugars. If you look at sources of these different carbohydrates, the glucose comes from fruit. That’s not the only place but that’s a primary source of it. You see the lactose of course from milk, and then when you get down to the cellulose, and we’re talking about starches and then fiber gets involved in here too, then cereals and vegetables become the primary source of these.

Are we eating too much or too little of these different classes of sugars? Well, as you might guess, we eat too much of the simple sugars and the disaccharide sugars and we eat too little of the complex carbohydrates. If you followed a diet where you ate less junk food and ate more fruits and vegetables, for example, just those two little rules you would help shift around this balance of sugars in a way that would benefit health.

There’s sugar in a lot of foods where you don’t expect it. Of course there’s lots of sugar in donuts or ice cream, or pastries, or other things that are sweet; candy of course, but there are other places where you see it and you don’t necessarily expect it. As an example: peanut butter. Here’s a list of ingredients from Skippy Peanut Butter and you see that sugar is the second most common ingredient. You may know from reading food labels that these ingredients in any food label are listed in order of how much there is in the food itself, so sugar comes right after peanuts. Here’s another example, Beef Stew, you wouldn’t necessarily expect to find sugar in beef stew but it’s there. Now it’s down the list of ingredients, it’s actually toward the end, but if you look at the marketing of this and look at the can it says, there’s fresh potatoes and carrots, but actually there’s more sugar in this than there is carrots. So you wouldn’t eat something like beef stew and expect to find this to be the case.

Here’s another example where you have high fructose corn syrup is the source of sugar is in ketchup. If you start to look at food labels more carefully, what you’ll find is some version of sugar, and if you find ose, o-s-e at the end of something, that means it’s a sugar. And then of course, there’s the word sugar itself and then things like high fructose corn syrup, so there are a lot of ways that sugar gets put into foods and you wouldn’t expect it to be there.

How many of you have heard of the glycemic index? Okay, a lot of you have heard of it, it’s a very interesting concept. One that was developed a number of years ago but has been perfected and refined in recent years with very, very good research. There is a researcher at The Harvard Medical School named David Ludwig who’s done a terrific series of studies on the glycemic index and found how it relates to food intake, body weight regulation, and health. The idea here is that when foods get ingested in the body, they create different responses from each other depending on how they affect insulin and blood sugar, blood sugar especially. In some foods, those with a high glycemic index create a spike in blood sugar. Blood sugar goes up more then it does with foods that are low glycemic index foods, and this affects how hungry people are and potentially their health as well. The glycemic affect is the extent to which this blood sugar effect occurs when people consume certain foods and then the glycemic index is just a number that gets attached to that.

If you go to the web just type in glycemic index, you can pull up chart after chart of high and low glycemic index foods, and sometimes you get surprised by what those foods are. Let’s show you graphically how this might play out. Let’s create a graph here that on the x axis it’s going to be time, so time zero will be when you first take in a food and then one hour later, two hours later will be shown as you go from left to right, and then we’ll have blood glucose level up on the y axis. Now we’re going to compare high glycemic index foods with low glycemic index foods, and so the curve of blood sugar with high glycemic index foods, those that create an exaggerated blood sugar response over a period of time might look like this. Now the two things to notice about this are the high spike that you have out here which occurs very rapidly and then the rapid decline in blood sugar, and insulin is involved in this whole reaction. And so it’s thought and the research suggests this to be the case, that during this period of time here when the blood sugar is declining very rapidly and then when it goes down to below its initial level here — you see that — that people are especially hungry and want to eat more. The body is sending out signals that more eating is necessary.

The curve for the low glycemic index foods would like this. Let’s see if we can get it to go. There we go. So this looks much different, doesn’t it? A much smaller peak, a much less rapid decline after the peak occurs. The peak occurs a little bit later and then there’s a less rapid decline here, and then blood sugar actually ends up a little above this initial level, and therefore you’re less likely to eat because you’re less hungry. If we look at the two graphs in relationship to one another you see how different they are. Now when you want to maintain good health, high peaks, high spikes in blood glucose and the insulin response that provokes is not a very good thing, and so the red line is a far healthier way to be than the yellow line is. Then also, of course, if hunger is an issue and people are eating more than they want then you’d rather have the red line than the yellow line.

Avoiding foods that are high in sugar is a good idea to begin with, but then paying attention to the glycemic index research would suggest is a very good idea as well. So, as I said, there are many graphs around many charts of the high and low glycemic index foods and some things would surprise you. Like you wouldn’t expect bananas, for example, to be a high glycemic index food but it is. The foods that you see on the right probably don’t surprise you, because those are considered sort of healthy options as well. But the word white shows up a lot in the high glycemic index foods — white rice, white spaghetti, white bread. Does this mean that the glycemic index is the healthiest — following this sort of a plan that would come from this — is that the healthiest way to eat? Well not necessarily, because there are many different schemes that one can follow to eat a healthy diet. This is one. If one follows a diet that would be derived from the glycemic index; you’re likely to have a pretty healthy diet. But as I’ll mention in a few minutes, there are possible schemes that one can follow to get you to the goal line as well. But if one’s concerned about risk for Diabetes, which many people are, or have a family history of that, this glycemic index approach is not a bad one to pay attention to.

Chapter 3. Fats: Cholesterol, Hydrogenation and Saturation [00:19:05]

Okay, let’s talk about fat for a moment. As I mentioned before, fat has twice the calories per unit weight as protein and carbohydrate. So it’s a very efficient way of securing energy. If one were faced with starvation, then seeking out fat as we discussed before, is a pretty good idea, but if one is not deprived of calories, then having fat may not be so helpful. There are different kinds of fat that we’ll discuss in just a moment. It can come from animal sources and from vegetable sources, and the two have different impacts on health.

Several concepts that are relevant in the discussion of fat: cholesterol, hydrogenation, and saturation. First of all, most people believe that their cholesterol level in their body is determined by how much cholesterol they actually consume, so foods high in cholesterol would be bad in that sense and foods low in cholesterol would be good. In fact, people do consume foods with cholesterol, but most of the cholesterol in the body is synthesized from foods that don’t have cholesterol itself but have fat that the body turns into cholesterol. Eating a high fat diet but one that’s low in cholesterol can still potentially lead to high cholesterol levels. There are different kinds of cholesterol, and the first cut that people made at this were saying that there are things called HDL and LDL, which is high-density lipoproteins and low-density lipoproteins, the LDL. It was a major discovery when scientists in the last century found that HDL is good and LDL is bad because people always thought high cholesterol is bad, low is good, but in fact, there’s certain types of cholesterol, the HDL, that’s protective against things like heart disease and you want to have a higher level of that and a lower level of HDL. Now there are — these things have been sophisticated even more and refined into even different types of cholesterol having to do with the size of particles that we won’t get into in this class, but it’s very interesting how cholesterol is related to health and where the sources of cholesterol come from.

Hydrogenation is an interesting process and will bring us to the discussion of Trans fat in just a few minutes, but it’s basically when you hydrogenate a food you are altering its chemical properties to take a soft fat and make it more solid. So, stick margarine compared to tub margarine. The stick margarine has been hydrogenated to make it a more solid form. In this process, the margarine becomes less healthy. You see partially hydrogenated oils as an ingredient in many foods. That links to the Trans fat thing and you want — for health reasons it’s probably good not to eat too many of those. The saturation is interesting. You hear a lot about saturated fat, about polyunsaturated fat, monounsaturated fat. Those are all different chemical versions of fat, and again, the sophistication and the science has gotten so good that people used to think that just fat was bad, and overall that’s probably correct, but there are different kinds of fat and some are actually healthy and you want to have those in your diet, and other types of fat you want to have less of.

Trans fats have become a really interesting issue. There are groups of people who have studied the impact of Trans fats on health for a number of years. One of the primary characters in this whole scientific process is a researcher at Harvard named Walter Willett. His name will come up again in several contexts later in this class, and then also in subsequent classes because he’s a very fine nutrition researcher, one of the best in the world. Well, Willett and others were doing studies for a number of years finding that Trans fats were having a very negative impact on health, but nobody paid much attention and they couldn’t get much attention out there in the world for this kind of work.

What happened finally, is that the press got wind of this and the scientific evidence grew to such a large mass that the evidence was pretty overwhelming, and then finally, government took action on this. The press started writing a lot about Trans fats and then the government required Trans fats to be shown on labels, and then the food industry really had to pay attention and a lot of them started taking out Trans fats. There’s still plenty of it the food supply, believe me, but some companies have taken them out. For example, Frito-Lay, before they really had to because of bad publicity, took out all of the Trans fats in their products and that was — they’re the largest snack manufacturer in the world so that was a pretty significant advance for the healthiness of their foods. And other companies have followed suit, but not all of them, and there’s still as I said, a lot of Trans fats shows up in things. But in certain parts of the country you’re not able to eat Trans fats in restaurants because they’ve been banned. New York City took the lead in that and we’ll talk about that as a political issue later in the class.

What are Trans fats? They’re unsaturated fatty acids that get formed when foods are partially hydrogenated. Again, when you see that partially hydrogenated oils on an ingredient list, that means there’s Trans fat. Why would companies do this? Why would the food industry want to introduce Trans fat in the first place? Well, it changes the food in ways that are commercially appealing for the industry. It gives foods a longer shelf life, and so things like pastries and individual wrapped packages have a very long shelf life, longer then if they don’t have Trans fats. They tend to stay stable during deep frying and then the palatability goes up and the foods taste better, at least according to the food industry.

Now the fact is that the Trans fats can get switched out of foods in a pretty easy way by the industry, because now they’re doing it pretty routinely like all the restaurants in New York are having to do it, for an example. As a consequence, the taste hasn’t suffered, the prices for the industry haven’t gone up, the range of opportunities for consumers to eat foods they like hasn’t really shrunk, and so the Trans fat change has been beneficial for public health but hasn’t really affected the food industry in an adverse way. The whole country of Denmark banned Trans fats. It was the first time a country had taken action on that, so these are very positive public health changes. Trans fats are in a great many foods and if you start looking carefully at food labels you’ll see how many foods have Trans fats. It amounts to 2 to 3% of calories for the average consumer, and as I mentioned, Trans fats are not so good.

Getting back to the concept that there are good and bad fats, if we look at the left hand side here, is a table or a graphic showing the fats that tend to have beneficial impacts on health. Now don’t forget that the fat has calories. So you could have — be consuming fat that is in itself good for heart health let’s say, or maybe protective against cancer in some ways, but it’s also adding calories to the diet, so you want to have the optimal amount of fat and not over-consume it because of the calories. You have the monounsaturated fat. The olives, olive oils, and some nuts are high in the monounsaturated fats. We’ll link back to that when we talk in a few moments about the Mediterranean Diet. The unsaturated fats are the corn, soy bean, safflower, sunflower, cottonseed oils, and fats that you get from seafood. So you hear about the Omega-3 fatty acids coming from seafood and these tend to be protective against diseases.

These kinds of fats are necessarily bad, and so things like olive oil in the diet tends to be protective and they explain some regional variations in rates of heart disease. The bad fats look like this, and those are the saturated fats and the Trans fats. You can see down here its affect on cholesterol levels: that the bad fats raise the LDL levels, the low-density lipoproteins levels, that’s not good for you. And they raise the HDL — I mean it is good for you that — well let’s see, okay, no I got that wrong. It raises both LDL and LDL — this can’t be right. It probably lowers HDL but I’ll have to go back and check that. In any event, the saturated fats that are in these kinds of foods tend to be in the things that you associate with fatty foods like high fat, meat, whole milk, etc., have a bad impact. The Trans fats that we mentioned before that you can see listed over here from margarine, shortenings, deep fried foods, a lot of fast foods and baked goods have a negative impact on health as well.

It’s important for the public health to change the partitioning of fat so you move from bad to the better fats in the diets. Some of this can be done if consumers make different choices in what they eat, but some can be silent changes too, so Frito-Lay taking the Trans fats out of their products and switching them with a healthier fat is a silent change that could have a positive impact on public health. Now, it raises lots of interesting issues if a company does that and then boasts about it on the packaging or in marketing, because then people could overestimate how good those products are for them, so a lot of consumer education has to be done. But overall, those changes can be pretty helpful.

Chapter 4. Diet, Disease and Leading Causes of Death [00:29:28]

How many of you got your clickers? Anybody have any problem getting the clickers? Okay. Those of you who have your clickers let’s pull them out, what I’d like you to do, if anybody doesn’t have your clicker yet, please bring it to class. Please get one and bring it to class and we’re only going to do one these exercise with the clickers today just as a test, but in subsequent classes we’ll be using them quite a lot.

I’d like to talk about the leading causes of death and we’ll compare leading of causes of death in 1900 to leading causes of death today. It’s possible that the causes of death are the same; it’s possible they’ve changed, but we’ll see. What I’d like to do — and this will be the first time I’ve the clicker thing in the class — so let’s try out this little quiz and see how it works. I’d like to ask you what the biggest killer was in 1900. What — which of these things took the most lives in the United States? Pneumonia? Malaria? Cancer? Or heart disease? Okay, so with your little clicker you can press one, two, three, or four depending on which one of these you believe is the case and let’s see if the — if it registers. You know what? I forgot to hook it up. That’s one little problem with this clicker technology: you have to plug it in! Let’s see if we can get this done, and I promise the next time to actually have this connected. As we do these little clicker poll things you can tell me if you find it helpful or not, then we can decide how to continue — whether to continue them in the future. Let’s see if it recognizes, try voting — polling closed — not so good. Okay good, so it’s reading the responses now. Has everybody voted who has a clicker for one of these things? Fifty-two of you so far, so what we need are more people to get clickers, because some of these polls will be interesting to do. If the program works right here’s what people said, 81% said pneumonia, 15% malaria, 2% cancer, and 2% heart disease. Boy, you guys were right on with that. That’s exactly right. These are the leading causes of death in 1900. And so you can see the pneumonia, tuberculosis, the communicable diseases, infectious diseases, for the most part, are taking the most lives at that point. Things like heart disease and cancer are down the list. If you look at cancer, for example which is down here, only 3.7% of deaths, much smaller then the number today. What would that have been the case back then? Why would there have been so many fewer cases of cancer? Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, that’s exactly right. People lived shorter lives and so they didn’t get far enough into the age span to suffer from the chronic diseases that people are suffering more today. So this is an interesting picture. Now let’s look at what the present day holds the leading causes of death now and this is probably something that you’ll also know. That you put together diseases of the heart, cancer, stroke, and then chronic respiratory diseases, those first top four are accounting for a huge number of deaths. Again, these are chronic diseases the people get. Now in some — in the chronic respiratory diseases there’s some infection but most of the other things are caused by lifestyle or by other factors, not the infectious diseases. The partitioning of diseases has changed a lot in that period of time.

Now let’s see where diet comes into play here and how diet affects these different diseases. Now you get interesting relationships here because diet is related to heart disease, it’s related to cancer, it’s related to stroke, and it’s related to Diabetes. Now potentially to some of the other things as well, but these are the main ones, and these links have been very clearly established. You can see the overall contribution of diet to health is very important. When one thinks about changing the health of a population diet has to be considered one of the possible places to intervene. Chronic diseases have a major role in the healthcare costs, so if you look at these chronic diseases, heart disease, stroke, cancer and Diabetes we find that seven out of ten of all deaths are now due to chronic diseases, whereas, it was a very small fraction in 1900. Half of Americans have at least one, so it’s affecting a lot of the population. I don’t want to get too much into healthcare costs but these numbers are really pretty impressive: 75% of healthcare costs come from chronic diseases; heart disease and stroke alone cost 448 billion dollars, and Diabetes 164 billion dollars, so these are significant players in the national healthcare scheme.

Diet, as we said before, is having a big impact, so estimates are that you can attribute two point six million deaths per year globally to low intake of fruits and vegetables. Those same estimates say that if you could turn that around, that if the world could eat the recommended level of fruits and vegetables, that you’d reduce the prevalence of heart disease by 31%. Now, figure in the fact that smoking is playing a role, physical activity is playing a role, still just changing fruit and vegetable consumption potentially could reduce heart disease worldwide by this much: stroke by 19% and some cancers by as much as 20%. Changing the diet of populations is a pretty good idea and it’s the kind of thing that could help individuals certainly lead healthier, happier lives, but also could change things like healthcare costs for a whole country, so these are big, big factors.

Chapter 5. Linking Diet and Health through Studies [00:36:21]

Let’s talk about how we know about the link of diet and health. There are a number of different methods that scientists use to see what foods are related to particular health outcomes, and we won’t go through all of them but I will — over the course of the class we’ll talk about various methods, but I’d like to talk about two primary ones today. One are epidemiology studies and then the second are intervention studies.

Now the epidemiology studies are observational studies. You’re not intervening with people, you’re observing usually large numbers of people in a population. You measure health and you measure a factor like diet, you measure other factors that might be related as well. So factors such as exercise, or smoking, or other things like this that are relevant will be measured and then the scientists will look at the impact of something like diet on health while controlling for the other factors, controlling for the impact of the other factors, so you can try to isolate the impact of the thing you’re interested in, in this case diet with — on the outcome of interest, let’s say heart disease or cancer. That’s how epidemiology is usually done.

Intervention studies are when you’re actually doing something with people. Let’s say you get ten thousand people in a large study. You want to look at the effect of a low fat diet. As I mentioned before is one example on the risk for breast cancer in women, so you’d randomly assign half to following their usual diet, the other half to an intervention program where people are prescribed a low fact diet, given counseling and interventions from dieticians and things, and then you look to see what happens for risk as people go forward in time. That would be an example of an intervention study.

Now the intervention studies are stronger methods then the epidemiology studies but they’re also more difficult studies to do. They cost more and they take a longer time. The epidemiology studies are what a lot of our information comes from. I’d like to give you examples of three of very famous epistudies on diet and health: The Framingham Heart Study, The Seven Country Study, and The Nurses’ Health Study, and then we’ll talk about some of the overall results from these sort of things. Okay, the Framingham Heart Study. Framingham is a town halfway between Worcester and Boston and you see it more or less in the middle of the map right here. There’s Framingham. A little town south of it, Hopkinton, anybody know what that’s famous for? Pardon me?

Student: [inaudible]

Professor Kelly Brownell: Yeah, the marathon. That’s where The Boston Marathon starts. But Framingham is famous for this heart disease study. It was undertaken with two primary figures at its head for many, many years. This is a picture of Bill Kannell on the right and Bill Castelli on the left who were physicians who were very prominent in this Framingham Heart Study over the years. It was launched in 1948 by The National Heart Institute, that later is now called The National Heart, Lung & Blood Institute, the NHLBI. This particular study was a prospective cohort. That means that a group of people who were identified and then re-measured every other year on — to getting blood tests and other biological markers, as well as doing assessments of their lifestyle behaviors and a number of other things. So when we talk about a cohort study, this means taking a group of people and following them over time.

It’s a more powerful method than something called a cross-sectional study, and I’ll come back in a later lecture and talk about these in more detail, but a cross-sectional study means you’re taking a snapshot of a population of people at one time. Let’s say you want to see how something like cigarette smoking is changing in the population and the rates of cigarette smoking, and you want to look at people every five years from 1970 to 2000. Well, a cross-sectional study would mean that you’d get a random group of the population and measure them in 1970 and then take another random group five years later and measure them, but it wouldn’t be the same people necessarily, it would be different groups of people. A cohort study means you take the same group of people and follow them every five years for that period of time.

Now in the case of The Framingham Study they did bi-annual assessments, every two years brought people into the lab and got very careful measures on them, so a lot of what we initially knew about diet and health, smoking and health, and other things came from The Framingham Heart Study. We did a study using the Framingham data ourselves several — some years ago where we were interested in the issue of weight cycling. That is, yo-yo dieting. In other words what happens to people’s health as they lose weight and then regain it repeatedly over a period time? The Framingham Study was perfect for that because you had these bi-annual assessments. You could take weights on people measured over a period of many years and look at the variability over time in weight and then link it to things like heart disease and cancer, and I’ll come back later and talk about the results of that particular study. That was a very famous study.

Another famous study was called The Seven Country Study done by a researcher at The University of Minnesota named Ancel Keys. Now he was very well known — he was a very good scientist and known for two different kinds of studies, much different from one another. There was The Seven Country Study, which was like The Framingham Study, where heart disease risk factors were mentioned, but he also did a very famous study on people starving. When we come back and talk about hunger in a subsequent class we’ll discuss that, but he did a very interesting study that’s been written about a lot, where he took conscientious objectors from World War II and who participated as volunteers in an experiment and starved them, I put them basically on about 75% of their usual calorie intake to see what happened to them over — psychologically and biologically over a period of time. The interest there was what do — can we learn about this because there were populations all over the world starving and scientists wanted to know what was happening physiologically to people and then what was the best way to re-feed them when you got — when they got access to food again? In The Seven Country Study, Keyes and colleagues started in 1950s and had cohorts of people, again groups of people followed over time, seventeen to eighteen of these cohorts over seven countries: Finland, Greece, Italy, Japan, The Netherlands, U.S. and Yugoslavia, and they’re still some follow-ups of these populations even to this day.

One of the initial things that Keyes found is that there was as much as a ten-fold difference in rates of coronary disease. The CHD stands for coronary heart disease — in — across these seven countries, from the lowest to the highest. As a consequence, he and other researchers then started looking into the lifestyles of people in these various countries to see what might help explain these differences in heart disease.

The Nurses’ Health Study is more recent and a very prominent study as well. This is done by researchers at The Harvard School of Public Health. Two of the key players there are Frank Speizer, a physician who got the study started, The Nurses’ Health Study I, that got started in 1976, and then Walter Willett who got Nurses’ Health Study II started ,and is still the principle investigator of these studies. Willett is a very prominent nutrition researcher and his name will come up in a variety of context in the class.

This study is very interesting because what it did was take nurses, a cohort of a hundred thousand nurses — my wife is actually — just happens to be one of the subjects in this study because she’s a nurse. What they do in this study is they took this cohort of a hundred thousand nurses and then have followed them repeatedly over the years, with very careful assessments of diet, health status, and other things, and countless papers, important papers have been published from this particular cohort. But it’s by far the largest study on women. They use food frequency questionnaires, which I mentioned before, surveys, and then biological markers like blood tests of certain things to see how diet is related to health. So a good bit of what we know about diet and health now comes from studies like The Nurses’ Health Study, and in the past, from studies like The Framingham Study and The Seven Country Study.

Chapter 6. Conclusions from Studies: Malnutrition and Its Consequences [00:45:16]

From all this we can conclude several things. First, let’s talk about malnutrition. Now usually that concept gets used to talk about too little nutrition, but in fact, if you consider mal to mean poor rather than too little, and poor nutrition can really get manifested as under-nutrition, over-nutrition, or just unhealthy eating in general. Now we’ll talk about each of these in class, some today and some in subsequent classes. Undernutrition or hunger is a major world problem. We’ll devote a whole class to that down the road just a bit. Overnutrition, with the obesity, we’ll talk about that some today, and then it’s possible that people have the correct number of calories, they’re not getting under-caloried or over-caloried, but the composition of the diet just isn’t so good, and so your risk for disease, no matter what your weight is, even if it’s normal weight can be elevated if you’re eating an unhealthy group of foods.

Under-nutrition — now I’m going — this slide has a lot of information on it and I’m going to come back to it in the class where we talk about hunger, but I show it today because of course undernutrition can affect every single system of the body and can have devastating consequences on people’s health. Of course death can be the final consequence of this, but even short of death, a number of very bad things can happen. But again, we’ll come and talk about this more when we discuss hunger, but there certainly are negative health consequences of undernutrition.

There are also very serious medical consequences of overnutrition. Just like hunger affects almost every system of the body, obesity does as well, and has consequences that are far ranging and long-lasting, and so overnutrition becomes a problem as well. Now again, I’m not expecting you to remember any of these sort of things or I’d linger more on the specifics, and this probably doesn’t come as a surprise to you, although it could be that the number of organ systems in the body that are affected might.

There’s one particular issue with overnutrition called the metabolic syndrome that I’d like to talk about and show you a little data on. The metabolic syndrome comes about from abdominal obesity. Now, I’ll discuss this again later in the class as well, but men and women tend to distribute fat in different parts of the body. When men gain weight they tend to distribute it above the waist, abdominal obesity, or what’s called the apple shape. Women tend to distribute the fat in the lower part of the body, below the waist, in what’s called a pear shape. Now when people gain enough weight they gain it all over their body, but those are the typical weight gain patterns and it happens for hormonal reasons. Current thinking is that women distribute the fat below the waist because it’s a fat storage depot for pregnancy and lactation. It’s the way to store energy in a place that protects it, packs it away, and keeps it for pregnancy and for nursing the baby, so it’s very important from a reproductive point of view.

For women, the good news is that that fat below the waist tends to do less physical damage than the fact above the waist that men more often have. It does appear that it’s harder to lose the weight below the waist, but there is some mixed research on that as well. Where fat is distributed is relevant, but both men and women can have fat above the waist in what’s called this abdominal obesity pattern. It’s connected with a number of things. You have elevated insulin levels, you have high fasting plasma glucose, so the blood sugar that we talked about before, impaired glucose tolerance, and an elevated triglyceride levels, low HDL cholesterol, (the good cholesterol), and hypertension. Again, I’m not expecting you to remember all the details of this but I’m going to show you this — when you put all these things together, it’s called the metabolic syndrome, and I’ll show you some data on its impact on health. Then there’s some interesting statistical things that you’ll see in these studies.

This first slide shows a graph of the impact of having metabolic syndrome on heart disease and its consequences. You’ll see a graph with yellow lines, yellow bars that are people without the metabolic syndrome and red bars are people with. We’re going to start at the right and work to the left. So using stroke as the outcome here, what you see is that people with the metabolic syndrome, the red bar, compared to the people without it, the yellow bar, have about twice the amount of risk. On the y axis here it’s the percent of people with these two conditions who have cardiovascular disease — or stroke rather 5% — less than 5% and a little over 5% with the stroke as the outcome. MI stands for heart attack, myocardial infarction, and in this case you see an even bigger differential of people with a metabolic syndrome having even more elevated risk then they did for stroke. Using coronary heart disease as the outcome you see about a quadrupling of risk in this case. That constellation of risk factors that gets packed together tells you more in some cases about a person’s risk for disease than if all you knew was their weight.

Now down — you’re going to see this sort of thing. I circled this P [ .001 over here that’s a — if any of you have taken statistics will know what that means, but it’s the statistical term that tells you how significant these findings are. Basically if you have a number that’s P [ .05 or lower, in this case, than the number is lower then that shows increasing level of statistical significance. Then when you see graphs like this and you see these stars, then that links down here to the significance level. So what this means is that this graph — this bar is significantly different from that one, this from that one, and this from that one, so they visually are different but they’re also statistically different.

Here’s another graph of data on the metabolic syndrome showing how it differs by race and ethnicity. You see the African-American individuals have a somewhat lower risk, although not a lot, from the white people individuals in this study, but the Mexican-Americans have elevated risk compared to the other two races. When you look at the risk of consequences from metabolic syndrome in the population, you have to know a person’s race to some extent to understand how high their risk really is. Certain parts of the population are more vulnerable to the health consequences given them — having the metabolic syndrome.

There are also interesting breakdowns by gender, and so if we look at the males and the females on the left here, you see that the females have a higher risk of consequences if they have metabolic syndrome then the males do. If you think back to the previous graph that I showed you about race, you can see how there will be an interaction of race and gender. So when you put together the race risk that was highest if — you may remember in the Mexican-Americans, and with the gender risk, higher rates in women, you’d expect the rates to be especially high in Mexican-American women, and in fact, that’s what you find. So more than doubling the risk in certain segments of the population. Now these kind of results show how important it is to do studies that don’t group everybody in the population together. Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, that’s a good question. The question is if women have less abdominal obesity, why would you find this elevated risk in women? It’s because these are the women who have abdominal obesity, so women are less likely to have it in the first place, but many do, and of those who do and have that metabolic syndrome, then they’re more susceptible to the heart disease outcomes then men are.

The — for ex — here’s an example. For many, many years almost all the studies on cancer in health were done in men. Women became very upset about this and advocacy groups like the breast cancer advocacy groups got involved and really pressured the government to do more studies on women. Once those studies were done, some very interesting differences started to show up along gender lines, and then other investigators started to look at race differences, and then you find things like this that are very interesting. They start to talk about who’s most susceptible in the population; who were the most vulnerable groups; and if you’re going to do intervention, who you may want to focus your efforts on. These are very interesting results, sort of the bias that everything should be done with white males that existed for many years hid some of these really interesting and important interactions that otherwise people didn’t know much about.

It’s also interesting that given the same level of nutritional problems — too much fat, too little fiber, too many calories, whatever it happens to be — not everybody is affected the same way, and some population groups are especially vulnerable, so we’ll talk more about that later as well. There are very interesting relationships between weight and risk for all diseases. In this case, death from heart disease and what you see here, and I’ll tell you what relative risk is in just a minute, but this is basically risk for disease over on this axis and here its weight. Expressed is body mass index. I’ll describe more about that later.

If you look at increasing weight as you go from left to right on this axis, lean people, overweight people, and obese people, the risk goes way up for death from cardiovascular diseases. The heavier a person is the more likely they are to die of cardiovascular disease. You find that the graphs for the men and the women, the orange and the yellow lines look pretty much the same, so there don’t appear to be any gender interactions until you get out here, and that’s a pretty small segment of the population.

There are several interesting things about this graph that I’d like to talk to you about. First is the body mass index, you’re going to see this a lot and you — some of you probably know about it already because it’s out there in the popular literature. It tends to be a better predictor of how much body fat a person has then just using their weight and I’ll talk more about body mass index in a subsequent class, but it’s basically weight over height squared in metric units, so it’s weight in kilograms over height in meters squared, and you come away with numbers in the teens, the twenties, and the thirties, and then if people are very heavy they can have higher body mass index then that. You’ll see that term a lot.

Relative risk of death is an interesting concept from public health. What this does, when you use relative risk you take some group of the population and you establish their risk as — at one. You just say that arbitrarily this group, the reference group, let’s say the group with the lowest weights, or the lowest cholesterol or anything, you say their risk is one, and then you look to see how everybody else’s risk is compared to that. If some group, let’s say you have cholesterol of two hundred and your relative risk is established at one, and then if you have cholesterol two hundred your relative risk is two, that means you have twice the risk, so relative risk of two is twice the risk, three is three times the risk, etc. You can see that when you get out to the highest groups here, the highest weights, the relative risk if up at two and a half or three, so that would be a 200% increase in risk for cardiovascular death or two to three times the risk of death. You’ll see that concept of relative risk come up in subsequent classes.

Now another interesting thing about this graph is right out here. People have referred to this as a J shaped curve with this little up tick in the left hand side and people — some people have sort of said, well maybe it’s not so bad to be overweight because it’s not so good to be underweight as well and that’s a problem. Those of you in public health and there are some grad students here have probably heard this discussion before, but you guys aside, can anybody guess what might be explaining this relationship over in the left hand side? Any ideas? What might be — go ahead?

Student: [inaudible]

Professor Kelly Brownell: Okay, so one possibility is that if somebody is underweight that creates its own set of heart consequences. Like somebody, for example, who has got extremely low weight might be that, and that explains part of it. That’s not what I was looking for but that’s part of the answer, so you’re absolutely right. Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, too little of the healthy fat to protect the body, that’s a possibility. Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, so the eating disorders that would — might push weight low might be causing some of the health consequences. Yes?

Student: [inaudible]

Professor Kelly Brownell: Okay, so if you’re underweight your body is depleting its fat stores and therefore that may make you unhealthy. These are all plausible reasons and possible contributors but nobody’s got the home run answer yet. Yes.

Student: [inaudible]

Professor Kelly Brownell: Okay, so it could be that people who were thin don’t think they have any thing to worry about might have other health behaviors that are interfering. Still nobody got the answer. Can you think of any behavior thing that people might do that would at the same time suppress weight and cause bad health consequences? Smoking, okay you got it. That little J shaped curve is explained primarily by cigarette smoking because that keeps weight down in people, it also makes people sick so that their weight gets low because of that, and it explains the high rates of the disease risk there. If you run these curves only on non-smokers you get rid of that J at the end of the curve and you get pretty much a function that’s to the right of the curve here. That’s a little interesting anecdote about the epidemiology of these things.

If you look at weight and risk of Type II Diabetes you start to see something pretty interesting. Now, here’s the relative risk again over here on the y axis, and so you can see here now you’re not just getting relative risks of two, three, or four but you’re getting relative risk of a hundred, in this case, massively elevated risk. As people’s weights get high — I’m sorry let’s go back here, got a little trigger happy here — as weights go high, from left to right you see the risk of Diabetes gets really very high.

Now, in the case of weight and cardiovascular disease, the lines depicting men and women don’t differ very much but here they do. There’s a pretty interesting and potentially important gender factor going on here where the women in the orange line, after about this point, start to diverge. So at a given level of overweight out here — twenty-seven, twenty-nine, thirty-one, thirty-three are the body mass index, the women are more likely to get Diabetes then the men are. They’re interesting biological reasons for that, but certainly it’s relevant, and it’s important of course for physicians to be aware of this when they’re screening overweight people for Diabetes given that excess risk in the women.

Chapter 7. What Should People Eat? [01:01:45]

Given these relationships between diet and health — you’ve got too few calories are bad, too many calories are bad, too much fat is bad, other things are good — then, what should people eat? Well, one way to understand what’s good to eat for you is first to know a little bit about what you’re eating, and that’s where that daily plate exercise came into play.

But it’s also important to understand what’s in foods and that’s why food labels are so important. We’ll just take a quick tour through a food label and discuss what this means. You may know that there are big fights being waged around the country now between governments that want restaurants to put calories on their labels — not on labels but on the restaurant menus, or on the menu boards in the restaurant, and the restaurant industry doesn’t want this at all. We’ll talk about that. When you go into a restaurant now, unless you want to go look at a board on the wall or get a pamphlet that may be hard to find, or go to the website, it’s going to be pretty hard to know what you’re eating in those foods. But packaged foods have labels, and this is made possible because of government action taken some years ago.

When you look at a food label like this, first it shows you the number of servings on containers. Of course you guys are savvy enough to know this, but a lot of people get fooled because many people believe that a serving is what’s ever in a bag, or a bottle, or a box, and they don’t look and see how many servings are actually in it. As a consequence, they’re underestimating the number of calories they’re consuming. So that’s part number one. Then you can look at the number of calories per — from fat that’s offered in the food,

Now, daily values are established by the government, how much nutrients the typical person needs and then how much — what percentage of that a food provides. In this case, the total fat, which is twelve grams, constitutes 18% of a day’s allowance of fat for the typical 200 calorie diet. Trans fats and saturated fat are also labeled on here and those are very helpful things. The mere fact of labeling Trans fat had a big impact on the food industry wanting to take it out. You got cholesterol, sodium, carbohydrate here, broken down as fiber and sugars, and that’s very helpful information to know. Then you can look at how this stacks up for a person that has a 200 calorie diet or a 2500 calorie diet, and it’ll show things like total fat, cholesterol, sodium, and total carbohydrate. Not much of a mystery to you guys because you’re used to reading these sort of things, but the food label can be very helpful.

It’s also very interesting to think about how the food label could change because this legislation comes up here and there and government consideration, and so if you guys have thoughts that you’d like to write about on one of your concept sheets about what could done to the food label to make it more effective, and more accessible to people, then feel free to write about that. Yes?

Student: [inaudible]

Professor Kelly Brownell: Percent daily — no, I don’t know why that’s not on there actually. It lists the protein but not the percent daily value, so you noted something interesting about the food label.

Now, let’s talk about healthy diets and what kind of diets people might optimally eat. One diet that gets discussed a fair amount, but mainly in recent years, is something called the Mediterranean Diet, and I’d like to discuss this for two reasons. One, there’s a growing amount of literature showing that Mediterranean — eating the Mediterranean Diet has protected against a number of diseases, but also there was a study on this that just came out on Friday, and I’d like to discuss the results of that particular study.

The Mediterranean Diet is high in olive oil, grains, fruits, nuts, vegetables, fish, and a moderate amount of red wine, and tends to be low in meat, dairy, and other alcohol. It got its name, of course, because there are parts of the world where people tend to eat this sort of a diet. Italy, Greece, some of the other Mediterranean countries have been studied in — in this context, and what made this interesting were observations going way back to The Seven Countries Study that were certain countries that had surprisingly low rates of heart disease, and people thought it might be the diet as one of the explanatory factors so it was important to look at. Now research has shown that to be the case.

What’s interesting about this particular diet? First you’ve got the mono and saturated oil that we discussed before. You’ve got things like grains and fruits that we know people should be eating. People don’t usually think so much of nuts as a protective part of the diet, but in fact they have some of the healthy fat as well, and then not surprisingly, vegetables and fish, and there is research as well showing that moderate alcohol intake is linked to lower risk of heart disease. Then the things on the right are pretty self-explanatory. This is a study that came out Friday in a journal called The British Medical Journal and this was a study of studies.

It wasn’t actually a study itself on the Mediterranean Diet, but it was a review of other studies that had been done using this statistical technique called meta-analysis. What this is, is you take a group of studies on an issue, you pool them all together, and then you weight studies differently depending on factors like how large they were, how good their methods were, and then you come out with overall estimates about the impact of something, in this case the Mediterranean Diet, on health outcomes. This pool, twelve very large studies, if you put all the number of subjects in those studies together, it would come up to a million and a half people.

They developed a score based on the results from these various studies on how carefully the subjects in these studies adhered to the Mediterranean Diet. It wasn’t the — in a place where they use the Mediterranean Diet or not — but it was how much did individuals actually follow the Mediterranean Diet and then they looked to see what impact that had on health. High adherence scores, good adherence to the Mediterranean Diet across all these studies, was associated with these particular health outcomes. So 9% less cardiovascular disease, 13% less Parkinson’s and Alzheimer’s, 6% less cancer, 9% less mortality from all causes. This is pretty good news and confirms what other studies had shown, but this is especially persuasive because it pools all those studies and draws from such a large number of subjects. It looks from this kind of thing like the Mediterranean Diet is one example of a healthy diet.

Now we talked before about a diet that would follow the glycemic index, that’s another pretty helpful method to follow. So when somebody is going to develop a healthy eating plan you can draw from a number of potentially beneficial structures. One is the Mediterranean Diet, another would be the glycemic index diet, and there are yet others.

When we talk about what to eat, how do we get advice on this and where do we look? Well, there’s kind of general advice on this that’s born partly on science but partly on philosophy of eating and foods and things like that.

A good example of that is Pollan’s book, In Defense of Food, that you started reading now. Now Pollan comes away in this book — it was a very clever way for him to summarize everything in his book into just a few words — but he says, eat food, not too much, mostly plants; and that’s what he’s known for in this particular book; and again, a very clever little way of remembering how to eat healthy. Now the first the eat food: well he has a long discussion, and as you’ll know from the book, about what is food? There are only certain things that qualify. Back to our hypothetical, you know, our initial discussion of Flaming Hot Cheetos: by his definition that would not qualify as food. So if you’re only eating food you wouldn’t eat things like that. There are other things that would qualify as food, but the not too much of course has to do with over — intake of certain nutrients, the calories; and then eating mostly plants tends to be a pretty good idea.

This is a broad, philosophical, partly scientific view of what people might eat, and it’s not a bad set of rules to follow. If the population would do more of this they’d be better off. You have these broad things, like if you just got the population to eat less junk food and more fruits and vegetables, well you might be 80% of the goal line or 90% of the goal line, so some broad rules pretty much apply.

Some people want more specificity about what to eat and there are some other examples of that. In this case, this book by Willett (the researcher that I mentioned before at Harvard), he’s written this book called Eat, Drink and Be Healthy, and it’s a very good guide. He’s a superb scientist. He knows the world’s literature on diet and health, and he’s taken all that information and put together into an eating plan in this particular book. If there’s — if you wanted a guide on how to eat healthy, this would be my favorite choice, would be the book Willett, Eat, Drink and Be Healthy, but there are others that are good as well.

Now, how does this get played out to the public? What kind of advice does the public get? Well, this is the original food guide pyramid, it’s supplemented by a more recent version and I’ll show you in just a second. The food guide pyramid was the government’s effort, put through by the U.S. Department of Agriculture about what people should eat optimally. Now this food guide pyramid was roundly criticized by some people in the nutrition community as being rife with conflicts of interest; that there was very heavy influence by the food industry, not only on the committees that created the report, but in revising drafts of the report once it came out, and then in the final guidelines.

People said the diary industry and the meat industry were especially effective at lobbying and that gave you a skewed version of what to eat. It’s what has been discussed in great detail in a terrific book by a researcher at NYU named Marian Nestle called, Food Politics. She was in Washington spending some time when the first food guide pyramid and dietary guidelines when being developed and she talks about that experience and how much impact the food industry had on this.

So There was great scrutiny and when the next food guide pyramid was getting developed. There was great scrutiny over the process. Most scientists believe that its better, a better process, less affected by conflicts of interest, but still affected by politics. The new food guide pyramid can be seen at and it looks like this. It’s a whole different pyramid. Lots of agonizing went into what sort of a graphic to create to do this. It shows several things. One is it shows that one should have a variety of foods. It also depicts physical activity. It shows in these parts of the pyramid that run vertically rather than horizontally, how much people should be eating of various foods. There’s an interesting set of politics that were involved in the creation of this pyramid that we’ll talk about as well in a subsequent class, but this is the reigning version of the pyramid.

Now one — people get very worked up about what the government nutrition guidelines are. People write about it, they lobby about it, they care a lot about it, the food industry spends a lot of time worrying about it, but some ways you could ask, who cares? What does it matter? Because the government spends so little money on educating about — people about nutrition, especially compared to what the food industry spends, that it doesn’t — it almost doesn’t matter what this is. You could take the food guide pyramid and make it the reverse of what it should be and you still end up with something that people really wouldn’t see very much, kids don’t learn about very much, it doesn’t really affect many people, so you could say that it doesn’t really matter.

Here’s a pyramid that was established from the glycemic index, so this would be a little bit different version of the pyramid. Here you see the main concern is what’s happening with blood sugar when people eat food. That’s not a bad one to follow either. And then the pyramid that I find most persuasive is the one developed by the folks at Harvard, Willett and his colleagues, that’s based on all the available science. You can look at that and get a better idea, and that’s less affected by lobbying and special interest than the government version.

Chapter 8. Cashing In on Nutrition Interest [01:15:23]

Okay, so I’d like to end with a little show of diet books and diet plans. Let’s just say you want to cash in on people’s nutrition interest. Well what can you do? Well you can promise miracles, there’s very little control over these sorts of things, you can distort the science, you can lie about what you do and nobody will come after you. It sounds like a pretty nice recipe for making a lot of money. You can write a diet book. There’s very little control over who writes these diet books or what goes into them. I’d just like to show you a few of these. They’re the magic nutrient books: carbohydrates, fat, whatever it happens to be, that’s one theme you could follow. You could also write a diet book regarding a place. There’s The South Beach, there’s Scarsdale, there’s Beverly Hills. There are a lot of places you could write a diet book about, but there are many more possibilities: Brazilian, Jerusalem, Greek, The Hilton Head Diet. They’re from all over the place, so you could make up your own one on that.

There are the specific food diets. There’s rice, coconut, cabbage soup diets, so you could use that kind of theme. What about the party — body part diet? Enzymes, thyroid, etc., the abs, the serotonin, you can pick some part of the body. The how long will it take you diets? There’s twenty-one days, there’s thirty days, there’s twenty-four hours. Now look at this! The three-hour diet, can’t beat that one! Only three hours to health and success. The egomaniac doctor diets. So these are diets where they put their name on the book like this, and of course, the classic one of all time was Dr. Atkins’ Diet Revolution.

There are religious diets that are interesting. If you want to draw upon a higher power you’ve got lots of choices there too. There’s a Buddhist version, there’s Daniel’s Diet over here. Now I don’t know if you can read it because it’s a little blurry, but a diet program that’s been successful over two thousand years; can’t beat that kind of a track record. Diets by numbers and letters — eDiets, Number Seven, The GI Diet.

There’s the weird diets but hard to classify: Detox Diet, The Rave Diet, so if you’re into raves you can go do that, and The Negative Calorie Diet, so these — the Negative Calorie Diet are ones that — where you eat food that have negative calories, so you consume it but it burns off more calories then it actually has. Not possible, but you could write a book about it. There’s the Butterfly Diet, the Astro Diet, the Get Well with Hay Diet. So if you’re like this you can do well with that. There’s the Diet Code, this is the weight loss secrets of Leonardo Da Vinci, and you probably didn’t know this, but see? That’s what happens with Leonardo. Here’s a nice little diet device. Here’s a soap that washes the fat away. You take a shower, you use this soap, the fat’s all gone. Here’s a nice device, food blocker, if you need a little help. Here’s another great one, lose weight in bed. So you need to lose weight? You can do it bed. Then here’s the favorite of all time, vacu-pants, attached via the hose to your vacuum cleaner. You want to lose weight? There are lots of possibilities. Okay we’ll see you guys on Wednesday.

[end of transcript]

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