Make me some science I can’t refuse

In case you missed it, in a recent article published in the American Journal of Preventive Medicine entitled Overstatement of Results in the Nutrition and Obesity Peer-Reviewed Literature (not making this up), the authors found that a lot of papers published in the field of obesity and nutrition have, shall we say, issues.

Well–as they say down South– I never!

The authors looked at over 900 scientific articles on nutrition or obesity published either in 2001 or 2011 in leading journals. They found that about 1 in 11 include “overreaching statements of results.” 

Here’s how the authors described statements that would be coded as “overreaching”:

  • reporting an associative relationship as causal
  • making policy recommendations based on observational data that show associations only (e.g., not cause and effect)
  • inappropriately generalizing to a population not represented by the sample studied

Frankly, I am totally offended. Someone needs to let these folks know that, in nutrition epidemiology, correlation actually does equal causation.

What’s more, nutrition policy recommendations are supposed to be based on observational data. Hello? Dietary Guidelines? (Seriously. You don’t expect public health nutrition people to do actual experiments now, do you? I mean, unless you are talking about our population-wide, no-control-group, 35-year experiment with low-fat diet recommendations, but that’s different.)

And we don’t mind generalizing conclusions to Everyone in the Whole Wide World based on data from a bunch of white health care professionals born before the atom bomb because, honestly, those are the only data we really care about.

Equating correlation and causation, over-generalizing observations, and then using these results as the basis of policy is the bread (whole wheat) and butter (substitute) of nutrition epidemiology of chronic disease (aka NECD – pronounced Southern-style as “nekked”). NECD has a long proud tradition of misinterpreting results this way, and dammit, nobody is going to take that away from us.

Early NECD researchers have in the past tried to tentatively misinterpret results by obliquely implying that observed nutritional patterns might perhaps have resulted in the disease under investigation. Wusses.

In 1990, Walter Willett and JoAnn Manson came along to show us how the pros do it. These mavericks were the ones who made bold inroads into the kind of overreaching conclusions that made NECD great. Their data come from an observational study of female registered nurses from 11 states in the US, born between 1921 and 1946, who were asked to remember and report what they ate 4 whole times between 1976 and 1984, plus remember and report what they weighed when they were 18 years old. From this dataset, which is clearly comprehensive, and this population, which is practically every female in the US, Willett, Manson and company naturally conclude that “obesity is a major cause of excess morbidity and mortality from coronary heart disease among women in the United States” (emphasis mine). None of this wimpy “associated with increased risk of” bullshooey, obesity CAUSES heart disease, they tell us, CAUSES IT!!!! BWHAAAHAAAAA!!!!!!!

It is on this foundation of intrepid willingness to misinterpret data that the science of NECD was built. This is why Walter Willett is the Big Kahuna at the Harvard School of Public Health. He has demonstrated the courage to misinterpret data in innovative and comprehensive ways, publishing articles throughout his career that indicate that even small increases in BMI—including BMI levels that are currently considered “normal”–cause chronic disease.

In 1999, in what is considered a landmark article in overstatement, one with which all NECD acolytes should familiarize themselves, he states unequivocally, in a review of observational data:

“Excess body fat is a cause of cardiovascular diseases, several important cancers, and numerous other medical conditions . . . “ (my emphasis). Hmmmm. Observed associations reported as causal? Ding!

The rest of that sentence reads: ” . . . and is a growing problem in many countries.” His data is once again gathered mostly from American white health care professionals born before the atom bomb. Generalization from specific populations to the rest of the world? Ding ding.

And what should we do with this conclusion, according to Willett? “Preventing weight gain and overweight among persons with healthy weights and avoiding further weight gain among those already overweight are important public health goals.” Using observed associations to make policy recommendations? Ding ding ding. In one fell swoop, Willett dexterously manages to use all three designated methods of overstatement and misinterpretation in the nutrition epidemiology NECD toolbox, demonstrating why he is considered by most researchers to be “the ‘father’ of nutrition epidemiology.” This man overstates and misinterprets in ways that the rest of us can only dream of doing.

Sadly, some epidemiologist have failed to follow in Willett’s footsteps. In January 2013, Katherine Flegal, an epidemiologist at the Centers for Disease Control and Prevention and the woman who first noted the remarkably rapid rise in obesity that began in the decade following the release of the 1977 Dietary Goals for Americans, published results that concluded that being overweight (or even mildly obese) is associated with a lower risk of death. At no point in her article does she suggest that overweight or obesity results in increased lifespan.

The response from Harvard? Walter Willett calls Flegal’s article ” a pile of rubbish” and insists that “no one should waste their time reading it” and rightly so. Why would anyone want to hear about “associations”? What kind of nonsense is that? Obviously Flegal lacks the professionalism it takes to make the leap from observation to causation.

But that’s okay. Willett and the Harvard Family know how to deal with this sort of thing.

“Someday, and that day appears to have come, I will call upon you to ignore the work of other scientists when their results contradict my own.”

Let’s face it, in the world of NECD, you can’t just have people like Flegal refusing to infer causation from observed results, just because they don’t want to. When that sort of thing happens, well, let’s just say, if she won’t do it, the Harvard Family will have to do it for her. And so they did.

In February 2013, Willett and company convened a Harvard Family gathering to, in their words, “elucidate inaccuracies in a recent high-profile JAMA article [i.e. Flegal's] which claimed that being overweight leads to reduced mortality” (emphasis mine). Which it didn’t–except now, voila, it does. It’s not personal, Dr. Flegal. It’s strictly science.

The Family get-together was held at the Harvard School of Public Health, a “neutral convening space” that is also ground zero for the Nurses’ Health Study I and II, the Physicians Health Study I and II, and the Health Professional Follow Up Study, three datasets that have generated many NECD articles that, unlike Flegal’s article, brilliantly illustrate the powers of misinterpreting observational data. That Flegal herself was invited, but “could not attend” tells us just how ashamed she must be of her inability to make over-reaching conclusions–or perhaps she was temporarily “incapacitated” if you know what I mean.

The webcast from the meeting show us how NECD should be done, with dazzling examples of overstatement and marvelous feats of misinterpretation.

In the world of NECD, PowerPoint arrows are a scientifically-acceptable method of establishing causation.

In her shining moment, Dr. JoAnn Manson, demonstrating that she has learned well from Willett, points to the slide above and asks: “How is it possible that overweight and obesity would cause all of these life-threatening conditions, increase their incidence, and then reduce mortality?” How indeed???

The panelists highlighted the importance of maintaining clear standards of overstatement and expressed concern that Flegal’s research could undermine future attempts of more credible researchers to misinterpret data as needed to protect the health of the public.

Because that’s what it’s all about folks: protection. Someone needs to protect the science from renegades like Flegal, and someone needs to protect the public from science.

We should be thankful that we have Willett and the Harvard Family there. They know that data like Flegal’s can only confuse the poor widdle brains of Americans. Allowing us to be exposed to such “rubbish” might lead us to the risky conclusion that perhaps overweight and mild obesity won’t cause all of us to die badly, or to the even more dangerous notion that observational data should remark only upon association, not causation. And we sure don’t want that to happen.

As Don Dr. Willett says, “It is important for people to have correct information about the relationship between health and body weight.” And when he wants us to have the correct information about the relationship between health and body weight, he’ll misinterpret it for us.

Take the science, leave the cannoli.

As the Calories Churn (Episode 2): Honey, It’s Not the Sugar

In the previous episode of As the Calories Churn, we looked at why it doesn’t really make sense to compare the carbohydrate intake of Americans in 1909 to the carbohydrate intake of Americans in 1997.  [The folks who read my blog, who always seem to be a lot smarter than me, have pointed out that, besides not being able to determine differing levels of waste and major environmental impacts such as a pre- or early-industrial labor force and transportation, there would also be significant differences in:  distribution and availability; what was acquired from hunted/home-grown foods; what came through the markets and ended up as animal rather than human feed; what other ingredients these carbohydrates would be packaged and processed with; and many other issues.  So in other words, we not comparing apples and oranges; we are comparing apples and Apple Jacks (TM).]

America in 1909 was very different from America in 1997, but America in 1970 was not so much, certainly with regard to some of the issues above that readers have raised.  By 1970, we had begun to settle into post-industrial America, with TVs in most homes and cars in most driveways.  We had a wide variety of highly-processed foods that were distributed through a massive transportation infrastructure throughout the country.

Beginning in the mid-1960s, availability of calories in the food supply, specifically from carbohydrates and fats had begun to creep up.  So did obesity.  It makes sense that this would be cause for concern from public health professionals and policymakers, who saw a looming health crisis ahead if measures weren’t taken–although others contended that our food supply was safer and more nutritious than it had ever been and that public health efforts should be focused on reducing smoking and environmental pollutants.

What emerged from the political and scientific tug-of-war that ensued (a story for another blog post) were the 1977 Dietary Goals for Americans.  These goals told us to eat more grains, cereals and vegetable oils and less fat, especially saturated fat.

Then, around 1977 – 1980, in other words around the time of the creation of the USDA’s recommendations to increase our intake of grains and cereals (both carbohydrate foods) and to decrease our intake of fatty foods, we saw the slope of availability of carbohydrate calories increase dramatically, while the slope of fat calories flattened–at least until the end of the 1990s (another story for another blog post).

[From food availability data, not adjusted for losses.]

The question is:  How did the changes in our food supply relate to the national dietary recommendations we were given in 1977?  Let’s take a closer look at the data that we have to work with on this question.

Dear astute and intelligent readers: From this point on, I am primarily using loss-adjusted food availability data rather than food availability data. Why? Because it is there, and it is a better estimate of actual consumption than unadjusted food availability data. It only goes back to around 1970, so you can’t use it for century-spanning comparisons, but if you are trying to do that, you’ve probably got another agenda besides improving estimation anyway. [If the following information makes you want to go back and make fun of my use of unadjusted food availability data in the previous post, go right ahead. In case you didn’t catch it, I think it is problematic to the point of absurdity to compare food availability data from the early 1900s to our current food system—too many changes and too many unknowns (see above).  On the other hand, while there are some differences, I think there are enough similarities in lifestyle and environment (apart from food) between 1970 and 2010 to make a better case for changes in diet and health being related to things apart from those influences.]

Here are the differences in types of food availability data: 

Food availability data: Food availability data measure the use of basic commodities, such as wheat, beef, and shell eggs for food products at the farm level or an early stage of processing. They do not measure food use of highly processed foods– –in their finished form. Highly processed foods–such as bakery products, frozen dinners, and soups—are not measured directly, but the data includes their less processed ingredients, such as sugar, flour, fresh vegetables, and fresh meat.

Loss-Adjusted Food Availability: Because food availability data do not account for all spoilage and waste that accumulates in the marketing system and is discarded in the home, the data typically overstate actual consumption. Food availability is adjusted for food loss, including spoilage, inedible components (such as bones in meat and pits in fruit), plate waste, and use as pet food.

The USDA likes to use unadjusted food availability data and call it “consumption” because, well: They CAN and who is going to stop them?

The USDA—and some bloggers too, I think—prefer unadjusted food availability data.  I guess they have decided that if American food manufacturers make it, then Americans MUST be eating it, loss-adjustments be damned. Our gluttony must somehow overcome our laziness, at least temporarily, as we dig the rejects and discards out of the landfills and pet dishes—how else could we get so darn fat?

I do understand the reluctance to use dietary intake data collected by NHANES, as all dietary intake data can be unreliable and problematic  (and not just the kind collected from fat people).  But I guess maybe if you’ve decided that Americans are being “highly inaccurate” about what they eat, then you figure it is okay be “highly inaccurate” right back at Americans about what you’ve decided to tell them about what they eat.  Because using food availability data and calling it “consumption” is to put it mildly, highly inaccurate, by a current difference of over 1000 calories.

On the other hand, it does sound waaaaaay more dramatic to say that Americans consumed 152 POUNDS (if only I could capitalize numbers!) per person of added sweeteners in 2000 (as it does here), than it does to say that we consumed 88 pounds per person that year (which is the loss-adjusted amount). Especially if you are intent on blaming the obesity crisis on sugar.

Which is kinda hard to do looking at the chart below.

Loss adjusted food availability:

Calories per day 1970 2010
Total 2076 2534 +458
Added fats and oils 338 562 +224
Flour and cereal products 429 596 +167
Poultry 75 158 +83
Added sugars and sweeteners 333 367 +34
Fruit 65 82 +17
Fish 12 14 +2
Butter 29 26 -3
Veggies 131 126 -5
Eggs 43 34 -9
Dairy 245 232 -13
Red meat* 349 267 -82
Plain whole milk 112 24 -88

*Red meat: beef, veal, pork, lamb

Anybody who thinks we did not change our diet dramatically between 1970 and the present either can’t read a dataset or is living in a special room with very soft bouncy walls. Why we changed our diet is still a matter of debate. Now, it is my working theory that the changes that you see above were precipitated, at least in part, by the advice given in the 1977 Dietary Goals for Americans, which was later institutionalized, despite all kinds of science and arguments to the contrary, as the first Dietary Guidelines for Americans in 1980.

Let’s see if my theory makes sense in light of the loss-adjusted food availability data above (and which I will loosely refer to as “consumption”).  The 1977 [2nd Edition] Dietary Goals for Americans say this:

#1 – Did we increase our consumption of grains? Yes. Whole? Maybe not so much, but our consumption of fiber went from 19 g per day in 1970 to 25 g per day in 2006 which is not much less than the 29 grams of fiber per day that we were consuming back in 1909 (this is from food availability data, not adjusted for loss, because it’s the only data that goes back to 1909).

The fruits and veggies question is a little more complicated. Availability data (adjusted for losses) suggests that veggie consumption went up about 12 pounds per person per year (sounds good, but that’s a little more than a whopping half an ounce a day), but that calories from veggies went down. Howzat? Apparently Americans were choosing less caloric veggies, and since reducing calories was part of the basic idea for insisting that we eat more of them, hooray on us. Our fruit intake went up by about an ounce a day; calories from fruit reflects that. So, while we didn’t increase our vegetable and fruit intake much, we did increase it. And just FYI, that minuscule improvement in veggie consumption didn’t come from potatoes. Combining fresh and frozen potato availability (adjusted for losses), our potato consumption declined ever so slightly.

#2 – Did we decrease our consumption of refined sweeteners? No. But we did not increase our consumption as much as some folks would like you to think. Teaspoons of added (caloric) sweeteners per person in our food supply (adjusted for waste) went from 21 in 1970 to 23 in 2010.  It is very possible that some people were consuming more sweeteners than other people since those numbers are population averages, but the math doesn’t work out so well if we are trying to blame added sweeteners for 2/3 of the population gaining weight.  It doesn’t matter how much you squint at the data to make it go all fuzzy, the numbers pretty much say that the amount of sweeteners in our food supply has not dramatically increased.

#3 – Did we decrease our consumption of total fat? Maybe, maybe not—depends on who you want to believe. According to dietary intake data (from our national food monitoring data, NHANES), in aggregate, we increased calories overall, specifically from carbohydrate food, and decreased calories from fat and protein. That’s not what our food supply data indicate above, but there you go.

Change in amount and type of calories consumed from 1971 to 2008
according to dietary intake data

There is general agreement , however, from both food availability data  and from intake data, that we decreased our consumption of the saturated fats that naturally occur with red meat, eggs, butter, and full-fat milk (see below), and we increased our consumption of “added fats and oils,” a category that consists almost exclusively of vegetable oils, which are predominantly polyunsaturated and which were added to foods–hence the category title–such as those inexpensive staples, grains and cereals, during processing.

#4 – Did we decrease our consumption of animal fat, and choose “meat, poultry, and fish which will reduce saturated fat intake”? Why yes, yes we did. Calories from red meat—the bearer of the dreaded saturated fat and all the curses that accompany it—declined in our food system, while poultry calories went up.

(So, I have just one itty-bitty request: Can we stop blaming the rise in obesity rates on burgers? Chicken nuggets, yes. KFC, yes. The buns the burgers come on, maybe. The fries, quite possibly. But not the burgers, because burgers are “red meat” and there was less red meat—specifically less beef—in our food supply to eat.)

Michael Pollan–ever the investigative journalist–insists that after 1977, “Meat consumption actually climbed” and that “We just heaped a bunch more carbs onto our plates, obscuring perhaps, but not replacing, the expanding chunk of animal protein squatting in the center.”   In the face of such a concrete and well-proven assumption, why bother even  looking at food supply data, which indicate that our protein from meat, poultry, fish, and eggs  “climbed” by just half an ounce?

In fact, there’s a fairly convenient balance between the calories from red meat that left the supply chain and the calories of chicken that replaced them. It seems we tried to get our animal protein from the sources that the Dietary Goals said were “healthier” for us.

#5 – Did we reduce our consumption of full-fat milk? Yes. And for those folks who contend this means we just started eating more cheese, well, it seems that’s pretty much what we did. However, overall decreases in milk consumption meant that overall calories from dairy fat went down.

#6 – Did we reduce our consumption of foods high in cholesterol? Yes, we did that too. Egg consumption had been declining since the relative affluence of post-war America made meat more affordable and as cholesterol fears began percolating through the scientific and medical community, but it continued to decline after the 1977 Goals.

#7 – Salt? No, we really haven’t changed our salt consumption much and perhaps that’s a good thing. But the connections between salt, calorie intake, and obesity are speculative at best and I’m not going to get into them here (although I do kinda get into them over here).

food supply and Dietary GoalsWhat I see when I look at the data is a good faith effort on the part of the American people to try to consume more of the foods they were told were “healthy,” such as grains and cereals, lean meat, and vegetable oils. We also tried to avoid the foods that we were told contained saturated fat—red meat, eggs, butter, full-fat milk—as these foods had been designated as particularly “unhealthy.” No, we didn’t reduce our sweetener consumption, but grains and cereals have added nearly 5 times more calories than sweeteners have to our food supply/intake.

Although the America of 1970 is more like the America of today than the America of 1909, some things have changed. Probably the most dramatic change between the America of the 1970s and the America of today is our food-health system. Women in the workplace, more suburban sprawl, changing demographics, increases in TV and other screen time—those were all changes that had been in the works for a long time before the 1977 Dietary Goals came along. But the idea that meat and eggs were “bad” for you? That was revolutionary.

And the rapid rises in obesity and chronic diseases that accompanied these changes? Those were pretty revolutionary as well.

One of my favorite things to luck upon on a Saturday morning in the 70s—aside from the Bugs Bunny-does-Wagner cartoon, “What’s Opera, Doc?“—were the public service announcements featuring Timer, an amorphous yellow blob with some sing-along information about nutrition:

You are what you eat

From your head down to your feet

Thinks like meat and eggs and fish you

Need to build up muscle tissue

Hello appetite control?

More protein!

Meat and eggs weren’t bad for you. They didn’t cause heart disease. You needed them to build up muscle tissue and to keep you from being hungry!

But in 1984, when this showed up on the cover of Time magazine (no relation to Timer the amorphous blob), I—along with a lot of other Americans—was forced to reconsider what I’d learned on those Saturday morning not that long ago:

My all-time favorite Timer PSA was this one:

When my get up and go has got up and went,

I hanker for a hunk of cheese.

When I’m dancing a hoedown

And my boots kinda slow down,

Or any time I’m weak in the knees . . .

I hanker for a hunk of

A slab or slice or chunk of–

A snack that is a winner

And yet won’t spoil my dinner–

I hanker for hunk of CHEESE!

In the 80s, when I took up my low-fat, vegetarian ways, I would still hanker for a hunk of cheese, but now I would look for low-fat, skim, or fat-free versions—or feel guilty about indulging in the full-fat versions that I still loved.

I’m no apologist for the food industry; such a dramatic change in our notions about “healthy food” clearly required some help from them, and they appear to have provided it in abundance.  And I’m not a fan of sugar-sweetened beverages or added sweeteners in general, but dumping the blame for our current health crisis primarily on caloric sweeteners is not only not supported by the data at hand, it frames the conversation in a way that works to the advantage of the food industry and gives our public health officials a “get out of jail free card”  for providing 35 years worth of lousy dietary guidance.

Next time on As the Calorie Churns, we’ll explore some of the interaction between consumers, industry, and public health nutrition recommendations. Stay tuned for the next episode, when you’ll get to hear Adele say: “Pollanomics: An approach to food economics that is sort of like the Field of Dreams—only with taco-flavored Doritos.”

As the Calories Churn (Episode 1): Nooooo, not the carbs!!!

Oh the drama!  Some of the current hyperventilating in the alternative nutrition community–sugar is toxic, insulin is evil, vegetable oils give you cancer, and running will kill you–has, much to my dismay, made the alternative nutrition community sound as shrill and crazed as the mainstream nutrition one.

When you have self-appointed nutrition experts food writers like Mark Bittman agreeing feverishly with a pediatric endocrinologist with years of clinical experience like Robert Lustig, we’ve crossed over into some weird nutrition Twilight Zone where fact, fantasy, and hype all swirl together in one giant twitter feed of incoherence meant, I think, to send us into a dark corner where we can do nothing but nibble on organic kale, mumble incoherently about inflammation and phytates, and await the zombie apocalypse.

No, carbohydrates are not evil—that’s right, not even sugar. If sugar were rat poison, one trip to the county fair in 4th grade would have killed me with a cotton candy overdose. Neither is insulin, now characterized as the serial killer of hormones (try explaining that to a person with type 1 diabetes).

But that doesn’t mean that 35 years of dietary advice to increase our grain and cereal consumption, while decreasing our fat and saturated fat consumption has been a good idea.

I have gotten rather tired of seeing this graph used as a central rationale for arguing that the changes in total carbohydrate intake over the past 30 years have not contributed to the rising rates of obesity.


The argument takes shapes on 2 fronts:

1) We ate 500 grams of carbohydrate per day in 1909 and 500 grams in 1997 and WE WEREN’T FAT IN 1909!

2) The other part of the argument is that the TYPE of carbohydrate has shifted over time. In 1909, we ate healthy, fiber-filled unrefined and unprocessed types of carbohydrates. Not like now.

Okay, let’s take closer look at that paper, shall we?  And then let’s look at what really matters:  the context.

The data used to make this graph are not consumption data, but food availability data. This is problematic in that it tells us how much of a nutrient was available in the food supply in any given year, but does not account for food waste, spoilage, and other losses. And in America, we currently waste a lot of food. 

According to the USDA, we currently lose over 1000 calories in our food supply–calories that don’t make it into our mouths.  Did we waste the same percentage of our food supply across the entire century? Truth is, we don’t know and we are not likely to find out—but I seriously doubt it. My mother and both my grandmothers—with memories of war and rationing fresh in their minds—would be no more likely to throw out anything remotely edible as they would be to do the Macarena. My mother has been known to put random bits of leftover food in soups, sloppy joes, and—famously—pancake batter. To this day, should your hand begin to move toward the compost bucket with a tablespoon of mashed potatoes scraped from the plate of a grandchild shedding cold virus like it was last week’s fashion, she will throw herself in front of the bucket and shriek, “NOOOOOO! Don’t throw that OUT! I’ll have that for lunch tomorrow.”

You know what this means folks: in 1909, we were likely eating MORE carbohydrate than we are today. (Or maybe in 1909, all those steelworkers pulling 12 hour days 7 days a week, just tossed out their sandwich crusts rather than eat them. It could happen.)

BUT–as with butts all over America including mine, it’s a really Big BUT: How do I explain the fact that Americans were eating GIANT STEAMING HEAPS OF CARBOHYDRATES back in 1909—and yet, and yet—they were NOT FAT!!??!!

Okay. Y’know. I’m up for this one. Not only is problematic to the point of absurdity to compare food availability data from the early 1900s to our current food system, life in general was a little different back then. At the turn of the century,

  • average life expectancy was around 50
  • the nation had 8,000 cars
  • and about 10 miles of paved roads.

In 1909, neither assembly lines nor the Titanic had happened yet.

The labor force looked a little different too:Labor force 1900 - 2000

Primary occupations made up the largest percentage of male workers (42%)—farmers, fisherman, miners, etc.—what we would now call manual laborers. Another 21% were “blue collar” jobs, craftsmen, machine operators, and laborers whose activities in those early days of the Industrial Revolution, before many things became mechanized, must have required a considerable amount of energy. And not only was the work hard, there was a lot of it. At the turn of the century, the average workweek was 59 hours, or close to 6 10-hour days. And it wasn’t just men working. As our country shifted from a rural agrarian economy to a more urban industrialized one, women and children worked both on the farms and in the factories.

This is what is called “context.”

In the past, nutrition epidemiologists have always considered caloric intake to be a surrogate marker for activity level. To quote Walter Willett himself:

“Indeed, in most instances total energy intake can be interpreted as a crude measure of physical activity . . . ” (in: Willett, Walter. Nutritional Epidemiology. Oxford University Press, 1998, p. 276).

It makes perfect sense that Americans would have a lot of carbohydrate and calories in their food supply in 1909. Carbohydrates have been—and still are—a cheap source of energy to fuel the working masses. But it makes little sense to compare the carbohydrate intake of the labor force of 1909 to the labor force of 1997, as in the graph at the beginning of this post (remember the beginning of this post?).

After decades of decline, carbohydrate availability experienced a little upturn from the mid 1960s to the late 1970s, when it began to climb rapidly. But generally speaking, carbohydrate intake was lower during that time than at any point previously.

I’m not crazy about food availability data, but to be consistent with the graph at the top of the page, here it is.

Data based on per capita quantities of food available for consumption:

1909 1975 Change
Total calories 3500 3100 -400
Carbohydrate calories 2008 1592 -416
Protein calories 404 372 -32
Total fat calories 1098 1260 +162
Saturated fat (grams) 52 47 -5
Mono- and polyunsaturated fat (grams) 540 738 +198
Fiber (grams) 29 20 -9

To me, it looks pretty much like it should with regard to context.  As our country went from pre- and early industrialized conditions to a fully-industrialized country of suburbs and station wagons, we were less active in 1970 than we were in 1909, so we consumed fewer calories. The calories we gave up were ones from the cheap sources of energy—carbohydrates—that would have been most readily available in the economy of a still-developing nation. Instead, we ate more fat.

We can’t separate out “added fats” from “naturally-present fats” from this data, but if we use saturated fat vs. mono- and polyunsaturated fats as proxies for animal fats vs. vegetable oils (yes, I know that animal fats have lots of mono- and polyunsaturated fats, but alas, such are the limitations of the dataset), then it looks like Americans were making use of the soybean oil that was beginning to be manufactured in abundance during the 1950s and 1960s and was making its way into our food supply.  (During this time, heart disease mortality was decreasing, an effect likely due more to warnings about the hazards of smoking, which began in earnest in 1964, than to dietary changes; although availability of unsaturated fats went up, that of saturated fats did not really go down.)

As for all those “healthy” carbohydrates that we were eating before we started getting fat? Using fiber as a proxy for level of “refinement” (as in the graph at the beginning of this post—remember the beginning of this post?), we seemed to be eating more refined carbohydrates in 1975 than in 1909—and yet, the obesity crisis was still yet a gleam in Walter Willett’s eyes.

While our lives in 1909 differed greatly from our current environment, our lives in the 1970s were not all that much different than they are now. I remember. As much as it pains me to confess this, I was there. I wore bell bottoms. I had a bike with a banana seat (used primarily for trips to the candy store to buy Pixie Straws). I did macramé. My parents had desk jobs, as did most adults I knew. No adult I knew “exercised” until we got new neighbors next door. I remember the first time our new next-door neighbor jogged around the block. My brothers and sister and I plastered our faces to the picture window in the living room to scream with excitement every time she ran by; it was no less bizarre than watching a bear ride a unicycle.

In 1970, more men had white-collar than blue-collar jobs; jobs that primarily consisted of manual labor had reached their nadir. Children were largely excluded from the labor force, and women, like men, had moved from farm and factory jobs to more white (or pink) collar work. The data on this is not great (in the 1970s, we hadn’t gotten that excited about exercise yet) but our best approximation is that about 35% of adults–one of whom was my neighbor–exercised regularly, with “regularly” defined as “20 minutes at least 3 days a week” of moderately intense exercise.  (Compare this definition, a total of 60 minutes a week, to the current recommendation, more than double that amount, of 150 minutes a week.)

Not too long ago, the 2000 Dietary Guidelines Advisory Committee (DGAC) recognized that environmental context—such as the difference between America in 1909 and America in 1970—might lead to or warrant dietary differences:

“There has been a long-standing belief among experts in nutrition that low-fat diets are most conducive to overall health. This belief is based on epidemiological evidence that countries in which very low fat diets are consumed have a relatively low prevalence of coronary heart disease, obesity, and some forms of cancer. For example, low rates of coronary heart disease have been observed in parts of the Far East where intakes of fat traditionally have been very low. However, populations in these countries tend to be rural, consume a limited variety of food, and have a high energy expenditure from manual labor. Therefore, the specific contribution of low-fat diets to low rates of chronic disease remains uncertain. Particularly germane is the question of whether a low-fat diet would benefit the American population, which is largely urban and sedentary and has a wide choice of foods.” [emphasis mine – although whether our population in 2000 was largely "sedentary" is arguable]

The 2000 DGAC goes on to say:

“The metabolic changes that accompany a marked reduction in fat intake could predispose to coronary heart disease and type 2 diabetes mellitus. For example, reducing the percentage of dietary fat to 20 percent of calories can induce a serum lipoprotein pattern called atherogenic dyslipidemia, which is characterized by elevated triglycerides, small-dense LDL, and low high-density lipoproteins (HDL). This lipoprotein pattern apparently predisposes to coronary heart disease. This blood lipid response to a high-carbohydrate diet was observed earlier and has been confirmed repeatedly. Consumption of high-carbohydrate diets also can produce an enhanced post-prandial response in glucose and insulin concentrations. In persons with insulin resistance, this response could predispose to type 2 diabetes mellitus.

The committee further held the concern that the previous priority given to a “low-fat intake” may lead people to believe that, as long as fat intake is low, the diet will be entirely healthful. This belief could engender an overconsumption of total calories in the form of carbohydrate, resulting in the adverse metabolic consequences of high carbohydrate diets. Further, the possibility that overconsumption of carbohydrate may contribute to obesity cannot be ignored. The committee noted reports that an increasing prevalence of obesity in the United States has corresponded roughly with an absolute increase in carbohydrate consumption.” [emphasis mine]

Hmmmm. Okay, folks, that was in 2000—THIRTEEN years ago. If the DGAC was concerned about increases in carbohydrate intake—absolute carbohydrate intake, not just sugars, but sugars and starches—13 years ago, how come nothing has changed in our federal nutrition policy since then?

I’m not going to blame you if your eyes glaze over during this next part, as I get down and geeky on you with some Dietary Guidelines backstory:

As with all versions of the Dietary Guidelines after 1980, the 2000 edition was based on a report submitted by the DGAC which indicated what changes should be made from the previous version of the Guidelines. And, as will all previous versions after 1980, the changes in the 2000 Dietary Guidelines were taken almost word-for-word from the suggestions given by the scientists on the DGAC, with few changes made by USDA or HHS staff. Although HHS and USDA took turns administrating the creation of the Guidelines, in 2000, no staff members from either agency were indicated as contributing to the writing of the final Guidelines.

But after those comments in 2000 about carbohydrates, things changed.

Beginning with the 2005 Dietary Guidelines, HHS and USDA staff members are in charge of writing the Guidelines, which are no longer considered to be a scientific document whose audience is the American public, but a policy document whose audience is nutrition educators, health professionals, and policymakers. Why and under whose direction this change took place is unknown.

The Dietary Guidelines process doesn’t have a lot of law holding it up. Most of what happens in regard to the Guidelines is a matter of bureaucracy, decision-making that takes place within USDA and HHS that is not handled by elected representatives but by government employees.

However, there is one mandate of importance: the National Nutrition Monitoring and Related Research Act of 1990, Public Law 445, 101st Cong., 2nd sess. (October 22, 1990), section 301. (P.L. 101-445) requires that “The information and guidelines contained in each report required under paragraph shall be based on the preponderance of the scientific and medical knowledge which is current at the time the report is prepared.”

The 2000 Dietary Guidelines were (at least theoretically) scientifically accurate because scientists were writing them. But beginning in 2005, the Dietary Guidelines document recognizes the contributions of an “Independent Scientific Review Panel who peer reviewed the recommendations of the document to ensure they were based on a preponderance of scientific evidence.” [To read the whole sordid story of the “Independent Scientific Review Panel,” which appears to neither be “independent” nor to “peer-review” the Guidelines, check out Healthy Nation Coalition’s Freedom of Information Act results.]  Long story short:  we don’t know who–if anyone–is making sure the Guidelines are based on a complete and current review of the science.

Did HHS and USDA not like the direction that it looked like the Guidelines were going to take–with all that crazy talk about too many carbohydrates – and therefore made sure the scientists on the DGAC were farther removed from the process of creating them?

Hmmmmm again.

Dr. Janet King, chairwoman of the 2005 DGAC had this to say, after her tenure creating the Guidelines was over: “Evidence has begun to accumulate suggesting that a lower intake of carbohydrate may be better for cardiovascular health.”

Dr. Joanne Slavin, a member of the 2010 DGAC had this to say, after her tenure creating the Guidelines was over: “I believe fat needs to go higher and carbs need to go down,” and “It is overall carbohydrate, not just sugar. Just to take sugar out is not going to have any impact on public health.”

It looks like, at least in 2005 and 2010, some well-respected scientists (respected well enough to make it onto the DGAC) thought that—in the context of our current environment—maybe our continuing advice to Americans to eat more carbohydrate and less fat wasn’t such a good idea.

I think it is at about this point that I begin to hear the wailing and gnashing of teeth of those who don’t think Americans ever followed this advice to begin with, because—goodness knows—if we had, we wouldn’t be so darn FAT!

So did Americans follow the advice handed out in those early dietary recommendations? Or did Solid Fats and Added Sugars (SoFAS—as the USDA/HHS like to call them—as in “get up offa yur SoFAS and work your fatty acids off”) made us the giant tubs of lard that we are just as the USDA/HHS says they did?

Stay tuned for the next episode of As the Calories Churn, when I attempt to settle those questions once and for all.  And you’ll hear a big yellow blob with stick legs named Timer say, “I hanker for a hunk of–a slab or slice or chunk of–I hanker for a hunk of cheese!”

Guest Post: James Woodward on Why Science May Not Be Enough

I’d like to introduce readers to a friend and fellow grad student, James Woodward. His undergraduate work was in economics at Ohio University, and he has a Master’s in public policy from the University of Kentucky. He is continuing at UK as a PhD student in public policy and administration. He and I have had some of the most thought-provoking email threads in any of my correspondence & I give him a lot of credit for helping me think through the economics and policy parts of food-health system reform puzzle. His post will serve as a bridge to my next series on “Eatanomics” which will explore how food, health, and the economy are intertwined. James would like everyone to know that all the disclaimers that appear on this page apply equally to what appears in this post. His views are his own, and as with the best of minds, he anticipates that most are subject to change. But he raises some very interesting questions—he’s nearly as long-winded as I am, but it is worth a read.

Why New Science May Not Be Enough – James Woodward

Before going into my social science background, I thought I would mention my professional background as it relates to food. It’s nearly as extensive as my academic background. I worked in fast food for about two years, a pizza place for about two years, a dining hall for a quarter, and, finally, a pseudo-Mexican restaurant for about two years. As a result, my feelings toward actual food and, especially, its preparation are fairly ambivalent at this point. The fact that I spent large amounts of time working with flour (I made tens of thousands of tortillas over the course of my tenure at the Mexican place) is rather ironic given my recent decision to avoid the stuff as much as possible.

Nutrition Science Initiative founders Gary Taubes and Peter Attia are hoping to give the public some solid science on food-health relationships.

My schooling in economics was concurrent with much of this work and my reasons for working these jobs had much more to do with my own economic situation than with any particular desire to work with food. But my background in economics and, now, public policy, leads to me to view the issue of food and nutrition policy a bit differently than many others writing on this topic. Many approach problems relating to nutrition and health in terms of their public health consequences. Others stress the fact that nutrition policy is the product of bad and/or misinterpreted science. Gary Taubes and Peter Attia just launched their organization, NuSI, to address, and hopefully settle, that particular aspect of this issue. Both lines of research clearly have their merits. Ultimately, though, I think what everyone is most interested in is influencing the behavior of individuals.

Contrary, perhaps, to Peter Attia’s quote from Richard Feynman in a recent blog post, I think there is a role for social scientists to play in understanding the many issues and controversies surrounding diet, health and public policy. Some of us in the social sciences are, in fact, sensitive to the difficulty of establishing real truths from the data available to us. Further, I do not think that social phenomena like behaviors and decision-making are reducible to physical and chemical relationships quite yet. How fitting that nutrition, and especially nutritional epidemiology, often bears more resemblance to bad social science than it does to any sort of ‘hard’ science.

Ignoring the controversy surrounding what it is that makes people fat and what constitutes an ideal diet, it would be hard to argue that people are making “good” decisions about what they are eating, given the high prevalence of (ostensibly) diet-related health problems in the United States, the most visible of which is obesity. Since most people buy their own food rather than growing or raising it themselves, food buying decisions tend to be highly correlated with food eating decisions. So, to me, the ultimate question is: “What influences food buying decisions?” Again, Gary and Peter have, with good reason, chosen to stress the importance of food consumption decisions being driven by good science. But there are clearly more factors that influence food purchasing decisions than a careful weighing of the scientific evidence. I would argue that such an approach to most decisions is, in fact, fairly rare. To the extent that Gary and Peter are ultimately trying to influence public policy, I think it is self-evident based on a reading of the history that policymakers are not that likely to employ such an approach either.

One of the many things besides science that may influence food purchasing and consumption.

This is why I tend to conceptualize the problem in the area of food and nutrition policy as one of bad information rather than attributing it purely to bad science. If one takes the time to dig, there is plenty of science which refutes the conventional wisdom regarding the relationship between diet and health. So, while no rigorous, carefully controlled studies have been performed to refute the conventional wisdom and/or confirm the “insulin hypothesis”, to use Gary’s term, there is already a lot of evidence to suggest that it is valid and plenty of evidence which refutes the conventional wisdom. Performing such a rigorous test of these competing theories is obviously warranted, given the importance of the implications for settling this debate, but there is no guarantee that the results will be convincing to skeptics, policymakers, stakeholders or the public at large.

Thirty-odd years ago policymakers perceived an obvious threat to public health (saturated fat) and saw a clear remedy (tell people not to eat so much saturated fat) which made it more or less a no-brainer to act on that information and tell people to avoid eating saturated fat containing foods. Since then, those original beliefs about diet and health have had time to percolate and become more or less embedded in how most people think about what they eat. Adele and I have talked a little bit about overcoming our own biases when we decided to eat differently, biases that we were not necessarily aware we had in the first place.

How you spend your food dollar may depend on how many food dollars you have to spend.

There are more factors that influence food purchasing decisions than just beliefs about how that food will affect one’s health. Taste, culture, geography, morality, ethics, politics, and socioeconomic status are just a few observable characteristics of an individual that might affect what he or she decides to eat. In many people’s minds, there is very little conflict between these concerns and health-related ones. For example, there is a perception that following a vegetarian lifestyle is good for one’s body, one’s soul, and the environment compared to a diet based around animal products. Upon closer inspection, however, there is a great deal of ambiguity to this belief in all three spheres. Similarly, many athletes seem to be operating under the impression that carbohydrates are required to perform at a high level. Peter’s well-documented experience calls that belief into question. Breakfast is often lauded as the most important meal of the day in the United States yet I frequently snub it to no ill-effect. And so on.

I think it is important to keep these biases in mind when thinking about we’d like to go about changing behavior. It is tempting to think “if only the science were better” people’s behavior would change. This is clearly not enough, in my mind anyway. It is just as important to be convincing as it is to be right. If/when NuSi successfully settles this debate and has the biggest names in the field to back up its research; there is still the matter of convincing everyone else. NuSi does acknowledge this aspect of the issue, though I am interested to see how it is addressed in practice. There are the cognitive biases of all the other scientists to contend with. There are also the material and non-material incentives that seem to be ingrained in many of the stakeholders involved in this particular area of policy. For example, it has been noted elsewhere that stressing the importance of calories is convenient for those involved in the production of food since doing so means no particular foods (e.g., wheat and sugar) are likely to be admonished against because of their unique effects on the body per se but, rather, because of their caloric content. I have to imagine that such firms will do their very best to refute any evidence that says otherwise and may hire their own experts to do so.

In a “calories in, calories out” world, there’s room for all foods in a “healthy” diet.

Beyond the obvious material costs to stakeholders of changing the current nutritional paradigm are the much more difficult to quantify costs of changing people’s beliefs about such things. Despite taking a nutrition course years ago (for an easy science credit, I will admit), I did not have particularly strong thoughts about nutrition prior to about a year and a half ago. I knew I made less than optimal choices about what I ate (according to conventional wisdom that is) but I mostly ignored those concerns since my health seemed fine (more or less). It was therefore fairly costless for me to change my mind about how I approach my diet after the conventional wisdom failed for me. Physicians and dietitians are not like me, however. Many of them have devoted years of their lives to dispensing information and advice that they believe to be correct and helpful. Faced with an opposing and incongruent view, it is perfectly understandable that they would be very resistant to the implication that they have been misleading their patients. In a less extreme form, I am sometimes asked by friends and acquaintances for my thoughts relating to diet and health and then, after giving them, met with resistance and facts or beliefs that supposedly refute my position(s). Most of these people are not experts on this topic but, like most people, they need some justification for what they believe.

So what is my point in all this? It is probably not breaking news that people’s eating decisions are not purely based on a careful reading of the scientific evidence. Better science is probably a necessary part of making the case but I do not think it will be sufficient to affect the type of change that many people in the ‘Paleo’ or ‘Ancestral Health’ communities (or whatever other term you prefer) would like to see. As mentioned, most people are averse to the notion that their beliefs are wrong and, in my experience, will try to come up with some reason for why that is not the case, sometimes resorting to questionable sources for support. This is human nature, I think– cognitive dissonance perhaps, to borrow a term from the psychologists. Based on what I can see, most people are not even willing to entertain the idea that there is a controversy or room for debate about these competing paradigms. Especially skinny people.

I think this state of affairs needs to change if further research is to bear any fruit in the form of affecting individual behavior and/or public policy. Fortunately, there are many bloggers writing on this topic, all bringing their own perspectives to the table. The challenge will be finding enough common ground to get this message to a larger audience so that we get an actual public debate going. I read the New York Times ‘Health’ section fairly regularly (as a barometer for this type of thing, not necessarily for good information) and I am not seeing it so far. It would be a real shame if all that came of this renewed interest in an old paradigm was a relatively minor reduction in the prevalence of obesity.

What Simon Doesn’t Say: An Expose with a Hidden Agenda

The Academy of Nutrition and Dietetics (AND) is squirming over a recent report written by Michele Simon of Eat Drink Politics that address ANDs corporate sponsorship program. The president of AND warns members not to believe everything they read and to mind the source (I supposed the assumption is RDs would be too sheep-like to do otherwise? Good thing Daddy Sheep warned us!), saying  ” . . . the majority of the report consists of publicly available facts filtered through the author’s opinions. She is of course entitled to her opinions. But opinions are not facts.”

I’m no fan of the Academy of Nutrition and Dietetics (AND), although they haven’t yet revoked my membership. I’m also no fan of industrialized food, although I do think the food industry has an important role to play in reforming our food-health system. I am also not a big fan of hypocrisy, which is why I have a good bit of trouble with the report, entitled Are America’s Nutrition Professionals in the Pocket of Big Food?

The answer is—I believe—a resounding “yes,” and Healthy Nation Coalition has explored how this compromised position extends not just to the food industry but the USDA itself. Clearly, the AND is an industry-friendly organization, and the USDA relies on AND-trained dietitians to confirm its own industry-friendly guidelines.

While I applaud Simon’s efforts to hold the AND more accountable for its relationships with industry, AND leadership is correct in pronouncing Simon’s reporting as one-sided and biased.  Simon is happy to slam the health-washing, cultural insensitivity, and hidden agendas of food manufacturers and the Academy, but if the propaganda, insensitivity, and agendas are vegatarian*—well, then she’s just fine with it, thank you very much.

“Healthy” smoothies are okay with Simon; meaty cheesy Big Macs are not.

Simon complains that “the banners at the McDonald’s booth showed images of healthy foods like smoothies,” but didn’t show McRibs and Big Macs. The implication, of course is that “healthy” smoothies” (with 78 grams of sugar and 4 grams of protein) aren’t so bad—even if they are from McDonald’s—compared to those meaty, cheesy foods like a Big Mac. Never mind that your body actually needs the protein that a Big Mac can provide and has little use for the 78 grams of sugar in a smoothie, except for fat storage.

How dare the Dairy Council target lactose-intolerant African-Americans! Every one knows all African-Americans would be healthier on a vegan diet . . .

Simon quotes an RD who points out that it is culturally inappropriate for the National Dairy Council to target African-American and Hispanic communities, considering the high rates of lactose intolerance in those populations, a remark with which I fully agree. Simon then goes on to complain about the inappropriateness of the Pork Board handing out educational material at “a nutrition conference where almost no countering information could be found about how a meat-centered diet can lead to chronic disease”?  In fact it would inappropriate to provide such “countering information” as the declaration that a meat-centered diet leads to disease is an ideological stance and not a scientific one. I would go on to add that it is also a culturally-insensitive stance, as pork is at the center of not only African-American and Hispanic food culture (barbeque, chorizo), but Chinese and Eastern European cuisine as well (lup cheong and kielbasa). It seems cultural sensitivity is fine if it means we can take away meaty, cheesy foods—but not when such sensitivity would allow them.

It’s not culturally insensitive to ban pork products–like these lup cheong– from a healthy diet; we’re just doing everyone a favor.

Simon’s take on the not-so-hidden relationships between the AND and the food industry is well-trod ground as she herself acknowledges, but to Simon some associations are apparently more odious than others:

In 1995, New York Times reporter Marian Burros wrote about criticisms of the [AND] for taking funding from industry groups such as the Sugar Association, the Meat Board, and companies such as McDonald’s, CocaCola, and Mars. According to Burros: “Nothing negative is ever included in materials produced by the association, a fact that critics attribute to its link to industry.” In that same article, veteran sustainable food advocate and Columbia University Professor Joan Gussow noted that giving money to registered dietitians is how industry silences its critics.

Simon pointedly calls out the National Cattleman’s Beef Association as an “especially loyal” sponsor. But if giving money means AND will only say positive things about your food product, it’s difficult to explain AND’s resounding endorsement of vegetarian and vegan diets, with “tips of the day” like “Endless Meat-Free Options” and articles that show you how to “Build Muscle, No Steak Required,” plus the promotion of stories such as “All Red Meat is Bad for You” in their daily newsletter. If I were the Beef Association, I’d want my money back.

Private consulting firms that have a “good” agenda don’t need to be held to the same levels of transparency as the “bad” ones.

I fully commend Simon’s calls for transparency, but the transparency knife cuts both ways. The AND/industry report was authored by Simon under the auspices of Eat Drink Politics, a self-described (by Simon) “industry watchdog” group that is also a “private consulting firm.” As such, while Simon is willing to disclose some of its clients, she states that “Some of our clients and funders prefer to remain anonymous for various reasons and we respect those wishes” (emphasis mine). So while she accuses the International Food Information Council of being “an industry front group” (which I think is pretty accurate), we can’t really tell who or what Eat Drink Politics is a “front” for, although we can take an educated guess.

The Eat Drink Politics website alerts us to an alarming situation regarding Deceptive Health Claims:

“The food industry has a challenge on its hands. Most health experts agree that the optimum diet is one based mostly on whole, plant foods, the kind that come from nature and not a factory. So, to convince Americans they can still eat their favorite meat, cheese, soda and junk food, many companies are using meaningless labels such as “all-natural” and engaging in other deceptive marketing practices” (emphasis mine).

Yup, meat and cheese—that’s about as un-natural as it comes.

It doesn’t take a rocket scientist to look through the science and figure out that “most health experts” don’t actually agree that the “optimum” diet is based mostly on whole, plant foods (actually I’m pretty sure it just takes a journalist, specifically Gary Taubes). It’s also pretty easy to figure out what Simon’s idea of a “whole, plant food” diet is:

“A diet based on whole plant foods minimizes or eliminates all animal products, including meat, poultry, fish, dairy, eggs, and their byproducts.”

Can you say—vegan?

Simon goes to great lengths in her book Appetite for Profit to deny that she has any vegan agenda, as she has been accused of by the Center for Consumer Freedom (a group Simon depicts—again, accurately, in my opinion—as a food and beverage industry front group).  She’s clearly sensitive to the fact that the word “vegan” is too loaded with negative connotations to actually use it when she suggests that “a diet that resembles my own would be optimal for most people.”

She accuses Center for Consumer Freedom of keeping its corporate sponsorship anonymous in order to engage in more provocative PR claims and of manipulating language to make it look like she’s pushing a personal agenda. But she seems pretty comfortable with keeping her own sponsors anonymous, with using provocative claims to alarm the public, and with using consumer-friendly language to gloss over aspects of her own personal biases that the public may find off-putting. I guess she figures it’s okay because she’s believes she’s got “decades of accepted nutrition science” and a “scientifically supported view” on the side of her personal nutritional biases.

I think Simon’s 5 recommendations to AND are long overdue. There is no doubt that AND would benefit from increased transparency; more input from members; sponsorship guidelines; an elimination of corporate-sponsored education; and stronger policy leadership.

But I cannot support is what I think is Simon’s most disturbing suggestion, that AND commit itself to policy action now—specifically taxation of sugar-sweetened beverages**—before a full review of scientific evidence and long-term implications can be ascertained.

According to Simon, “not every policy issue or decision can wait for months (or years) of committee review and analysis.” On the contrary, I would argue that more policy decisions that attempt to manipulate the health behaviors of Americans by relying on unproven assumptions about the relationships between food and health can and should wait for months or years or indefinitely, until consistent, quality experimental data is obtained or until observational data reveal consistent and unmistakably-high risks. Right now, the health crisis that Simon seems intent on addressing (and I applaud her intentions, if not her methods) is at least in part a result of sweeping changes made to our food system 35 years ago without such evidence in hand.

Simon’s unquestioning belief in her own nutritional agenda is a result of that policy experiment, but it isn’t the solution. It’s time we stop trying to change the eating habits of our fellow Americans—which is the underlying intention behind taxing soda and believing that a diet that resembles your own is best for everyone else—and start trying to change the regulatory, economic, and political framework that restricts access to both the food and the knowledge that individuals need to make their own decisions about their own health.

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In case you missed my interview with Bob Fenton, a fellow blogger who has type 2 diabetes, you can find it here: 

Adele holds forth on diabetes, dietetics, and why the refusal to admit the limitations of our nutrition knowledge is a dangerous thing.

Next up is a guest post from a friend and fellow graduate student, James Woodward, whose background in economics and public policy gives him a rather different perspective on how we might go about accomplishing the task of reforming our food-health system.  It will also provide a bridge to my next series on “Eatanomics” which will explore how food, health, and the economy are intertwined. 

*”Vegatarian” is a term I use to indicate veganism disguised as vegetarianism. While lacto-ovo-vegetarian dietary patterns are complete and perfectly healthy, vegan diets must rely on fortification or supplementation to be complete, as acknowledged by the promoters of such diets (just read the “fine print”).

**Sugar-sweetened beverages are usually pretty nutritionally useless, but we simply don’t know what sort of unintended repercussions a soda tax will have, or where to draw the taxation line. One study has shown that beer-drinking households responded to a six-month soft drink tax by buying more beer.

Not Just Science: How nutrition got stuck in the past

Nostalgia for a misremembered past is no basis for governing a diverse and advancing nation.

David Frum

The truth is that I get most of my political insight from Mad Magazine; they offer the most balanced commentary by far. However, I’ve been very interested in the fallout from the recent election, much more so than I was in the election itself; it’s like watching a Britney Spears meltdown, only with power ties. I kept hearing the phrase “epistemic closure” and finally had to look it up. Now, whether or not the Republican party suffers from it, I don’t care (and won’t bother arguing about), but it undeniably describes the current state of nutrition. “Epistemic closure” refers to a type of close-mindedness that precludes any questioning of the prevailing dogma to the extent that the experts, leaders, and pundits of a particular paradigm:

“become worryingly untethered from reality”

“develop a distorted sense of priorities”

and are “voluntarily putting themselves in the same cocoon”

Forget about the Republicans. Does this not perfectly describe the public health leaders that are still clinging blindly to the past 35 years of nutritional policy?  The folks at USDA/HHS live in their own little bubble, listening only to their own experts, pretending that the world they live in now can be returned to an imaginary 1970s America, where children frolicked outside after downing a hearty breakfast of sugarless oat cereal and grown-ups walked to their physically-demanding jobs toting homemade lunches of hearty rye bread and shiny red apples.

Remember when all the families in America got their exercise playing outside together—including mom, dad, and the maid? Yeah, me neither.

So let me rephrase David Frum’s quote above for my own purposes: Nostalgia for a misremembered past is no basis for feeding a diverse and advancing nation.

If you listen to USDA/HHS, our current dietary recommendations are a culmination of science built over the past 35 years on the solid foundation of scientific certainty translated into public health policy. But this misremembered scientific certainty wasn’t there then and it isn’t here now; the early supporters of the Guidelines were very aware that they had not convinced the scientific community that they had a preponderance of evidence behind them [1]. Enter the first bit of mommy-state* government overreach. When George McGovern’s (D) Senate Select Committee came up with the 1977 Dietary Goals for Americans, it was a well-meaning approach to not only reduce chronic disease, a clear public health concern, but to return us all to a more “natural” way of eating. This last bit of ideology reflected a secular trend manifested in the form of the Dean Ornish-friendly Diet for a Small Planet, a vegetarian cookbook that smushed the humanitarian and environmental concerns of meat-eating in with some flimsy nutritional considerations, promising that a plant-based diet was the best way to feed the hungry, save the planet, safeguard your health, and usher in the Age of Aquarius.  This was a pop culture warm-fuzzy with which the “traditional emphasis on the biochemistry of disease” could not compete [2].

If you listen to some folks, the goofy low-fat, high-carb, calories in-calories out approach can be blamed entirely on this attempt of the Democrats to institutionalize food morality. But, let’s not forget that the stage for the Dietary Guidelines fiasco was set earlier by Secretary of Agriculture Earl Butz, an economist with many ties to large agricultural corporations who was appointed by a Republican president. He initiated the “fencerow to fencerow” policies that would start the shift of farm animals from pastureland to feed lots, increasing the efficiency of food production because what corn didn’t go into cows could go into humans, including the oils that were a by-product of turning crops into animal feed.

When Giant Agribusiness—they’re not stupid, y’know—figured out that industrialized agriculture had just gotten fairydusted with tree-hugging liberalism in the form of the USDA Guidelines, they must have been wetting their collective panties. The oil-refining process became an end in itself for the food industry, supported by the notion that polyunsaturated fats from plants were better for you than saturated fats from animals, even though evidence for this began to appear only after the Guidelines were already created and only through the status quo-confirming channels of nutrition epidemiology, a field anchored solidly in the crimson halls of Harvard by Walter Willett himself.

Between Earl Butz and McGovern’s “barefoot boys of nutrition,” somehow corn oil from refineries like this became more “natural” than the fat that comes, well, naturally, from animals.

And here we are, 35 years later, trying to untie a Gordian knot of weak science and powerful industry cemented together by the mutual embarrassment of both political orientations. The entrenched liberal ivory-tower interests don’t want look stupid by having to admit that the 3 decades of public health policy they created and have tried to enforce have failed miserably. The entrenched big-business-supporting conservative interests don’t want to look stupid by having to admit that Giant Agribusiness, whose welfare they protect, is now driving up government spending on healthcare by acting like the cigarette industry did in the past and for much the same reasons.

These overlapping/competing agendas have created the schizophrenic, conjoined twins of a food industry-vegatarian coalition, draped together in the authority of government policy. Here the vegans (who generally seem to be politically liberal rather than conservative, although I’m sure there are exceptions) play the part of a vocal minority of food fundamentalists whose ideology brooks no compromise. (I will defend eternally the right for a vegan–or any fundamentalist–to choose his/her own way of life; I draw the line at having it imposed on anyone else–and I squirm a great deal if someone asks me if that includes children.)  The extent to which vegan ideology and USDA/HHS ideology overlap has got to be a strange bedfellow moment for each, but there’s no doubt that the USDA/HHS’s endorsement of vegan diets is a coup for both. USDA/HHS earns a politically-correct gold star for their true constituents in the academic-scientific-industrial complex, and vegans get the nutritional stamp of approval for a way of eating that, until recently, was considered by nutritionists to be inadequate, especially for children.

Like this chicken, the USDA/HHS loves vegans—at least enough to endorse vegan diets as a “healthy eating pattern.”

But if the current alternative nutrition movement is allegedly representing the disenfranchised eaters all over America who have been left out of this bizarre coalition, let us remember that, in many ways, the “alternative” is really just more of the same. The McGovern hippies gave us “eat more grains and cereals, less meat and fat,” now the Republican/Libertarian-leaning low-carb/primaleo folks have the same idea only the other way around—and with the same justification.  “Eat more meat and fat, fewer grains and cereals;” it’s a more “natural” way to eat.

As counterparts to the fundamentalist vegans, we have the Occupy Wall street folks of the alternative nutrition community—raw meaters who sleep on the floor of their caves and squat over their compost toilets after chi running in their Vibrams. They’re adorably sincere, if a little grubby, and they have no clue how badly all the notions they cherish would get beaten in a fight with the reality of middle-Americans trying to make it to PTA meeting.

How paleo might look from the outside.

To paraphrase David Frum again, the way forward in food-health reform is collaborative work, and although we all have our own dietary beliefs, food preferences, and lifestyle idiosyncrasies  the immediate need is for a plan with just this one goal: we must emancipate ourselves from prior mistakes and adapt to contemporary realities.

Because the world in which we live is not the Brady Bunch world that the many of us in nutrition seem to think it is.

Frum makes the point that in 1980, when the Dietary Guidelines were first officially issued from the USDA, this was still an overwhelmingly white country. “Today, a majority of the population under age 18 traces its origins to Latin America, Africa, or Asia. Back then, America remained a relatively young country, with a median age of exactly 30 years. Today, over-80 is the fastest-growing age cohort, and the median age has surpassed 37.” Yet our nutrition recommendations have not changed from those originally created on a weak science base of studies done on middle-aged white people. To this day, we continue to make nutrition policy decisions on outcomes found in databases that are 97% white. The food-health needs of our country are far more diverse now, culturally and biologically. And another top-down, one-size-fits-all approach from the alternative nutrition community won’t address that issue any more adequately than the current USDA/HHS one.

For those who think the answer is to “just eat real food,” here’s another reality check: “In 1980, young women had only just recently entered the workforce in large numbers. Today, our leading labor-market worry is the number of young men who are exiting.” That means that unless these guys are exiting the workforce to go home and cook dinner, the idea that the solution to our obesity crisis lies in someone in each American household willingly taking up the mind-numbingly repetitive and eternally thankless chore of putting “real food” on the table for the folks at home 1 or more times a day for years on end—well, it’s as much a fantasy as Karl Rove’s Ohio outcome.

David Frum points out that “In 1980, our top environmental concerns involved risks to the health of individual human beings. Today, after 30 years of progress toward cleaner air and water, we must now worry about the health of the whole planetary climate system.” Today, our people and our environment are both sicker than ever. We can point our fingers at meat-eaters, but saying we now grow industrialized crops in order to feed them to livestock is like saying we drill for oil to make Vaseline. The fact that we can use the byproducts of oil extraction to make other things—like Vaseline or livestock feed—is a happy value-added efficiency in the system, no longer its raison d’etre. Concentrated vertical integration has undermined the once-proud tradition of land stewardship in farming. Giving this power back to farmers means taking some power away from Giant Agribusiness, and neither party has the political will to do that, especially when together they can demonize  livestock-eating while promoting corn oil refineries.

If we all just stopped eating meat, then we wouldn’t have to plant so much corn, right? Right?

And it’s not just our food system that has changed: “In 1980, 79 percent of Americans under age 65 were covered by employer-provided health-insurance plans, a level that had held constant since the mid-1960s. Back then, health-care costs accounted for only about one 10th of the federal budget. Since 1980, private health coverage has shriveled, leaving some 45 million people uninsured. Health care now consumes one quarter of all federal dollars, rapidly rising toward one third—and that’s without considering the costs of Obamacare.”  That the plant-based diet that was institutionalized by liberal forces and industrialized by conservative ones is a primary part of this enormous rise in healthcare costs is something no one on either side of the table wants to examine. Diabetes—the symptoms of which are fairly easily reversed by a diet that excludes most industrialized food products and focuses on meat, eggs, and veggies—is the nightmare in the closet of both political ideologies.

David Frum quotes the warning from  British conservative, the Marquess of Salisbury, “The commonest error in politics is sticking to the carcass of dead policies.”

Right now, it is in the best interest of both parties to stick to our dead nutrition policies and dump the ultimate blame on the individuals (we gave you sidewalks and vegetable stands–and you’re still fat! cry the Democrats; we let the food industry have free reign so you could make your own food choices–and you’re still fat! cry the Republicans). It’s a powerful coalition, resistant to change no matter who is in control of the White House or Congress.

What can be done about it, if anything? To paraphrase Frum once again, a 21st century food-health system must be economically inclusive, environmentally responsible, culturally modern, and intellectually credible.

We can start the process by stopping with the finger-pointing and blame game, shedding our collective delusions about the past and the present, and recognizing the multiplicity of concerns that must be addressed in our current reality. Let’s begin by acknowledging that—for the most part—the people in the spotlight on either side of the nutrition debate don’t represent the folks most affected by federal food-health policies. It is our job as leaders, in any party and for any nutritional paradigm, to represent those folks first, before our own interests, funding streams, pet theories, or personal ideologies. If we don’t, each group—from the vegatarians to folks at Harvard to the primaleos—runs the risk of suffering from its own embarrassing form of epistemic closure.

Let’s quit bickering and get to work.

**********************************************************

*This was too brilliant to leave buried in the comments section:

“Don’t you remember the phrase “wait til your father gets home”? You want to know what the state is? It’s Big Daddy. Doesn’t give a damn about the day to day scut, just swoops in to rescue when things get out of hand and then takes all the credit when the kids turn out well, whether it’s deserved or not. Equates spending money with parenting, too.”–from Dana

So from henceforth, all my “mommy-state” notions are hereby replaced with “Big Daddy,” a more accurate and appropriate metaphor.  And I never metaphor I didn’t like.

References:

1. See Select Committee on Nutrition and Human Needs of the United States Senate. Dietary Goals for the United States. 2nd ed. Washington, DC: US Government Printing Office; 1977b. Dr. Mark Hegsted, Professor of Nutrition at Harvard School of Public Health and an early supporter of the 1977 Goals, acknowledged their lack of scientific support at the press conference announcing their release: “There will undoubtedly be many people who will say we have not proven our point; we have not demonstrated that the dietary modifications we recommend will yield the dividends expected . . . “

2. Broad, WJ. Jump in Funding Feeds Research on Nutrition. Science, New Series, Vol 204. No. 4397 (June 8, 1979). Pp. 1060-1061 + 1063-1064. In a series of articles in Science in 1979, William Broad details the political drama that allowed the “barefoot boys of nutrition” from McGovern’s committee to put nutrition in the hands of the USDA.

Why Race Doesn’t Matter in Nutrition Policy

This is the first of a series looking at what does and doesn’t matter when it comes to nutrition policy. When I started out on this adventure, I thought that science would give me the answers to the questions I had about why public health and clinical recommendations for nutrition were so limited. Silly me. The science part is easy. But policy, politics, economics, industry, media framing, the scientific bureaucracy, cultural bias—now that stuff is crazy complicated. It’s like an onion: when you start peeling back the layers, you just want to cry. I am also honored to say that this post is part of the Diversity in Science Carnival on Latino / Hispanic Health: Science and Advocacy

When we began investigating relationships between diet and chronic disease, we didn’t pay much attention to race. The longest-running study of the relationship between dietary factors and chronic disease is the Framingham Heart Study, a study made up entirely of white, middle-class participants. Since 1951, the Framingham study has generated over 2 thousand journal articles and retains a central place in the creation of public health nutrition policy recommendations for all Americans.

More recent datasets—especially the large ones—are nearly as demographically skewed.

The Nurses’ Health Study is 97% Caucasian and consists of 122,000 married registered nurses who were between the ages of 30 and 55 when the study began in 1976. An additional 116,686 nurses ages 25 – 42 were added in 1989, but the racial demographics remained unchanged.

The Health Professionals’ Follow-up Study began in 1986, as a complementary dataset to the Nurses’ Health Study. It is 97% Caucasian and consists, as the name suggests, of 51, 529 men who were health professionals, aged 40-75, when the study began.

The Physicians’ Health Study began in 1982, with 29, 071 men between the ages of 40-84. The second phase started in 1997, adding men who were then over 50. Of participants whose race is indicated, 91% are Caucasian, 4.5% are Asian/Pacific Islander, 2% are Hispanic, and less than 1% are African-American or American Indian. I have detailed information about the racial subgroups of this dataset because I had to write the folks at Harvard and ask for them. Race was of such little interest that the racial composition of the participants is never mentioned in the articles generated from this dataset.

Over the years, these three mostly-white datasets have generated more journal articles than five of the more diverse datasets all put together.* These three datasets, all administered by Harvard, have been used to generate some of the more sensationalist nutrition headlines of the past few years–red meat kills, for instance–with virtually no discussion about the fact that the findings apply to a population–mostly white, middle to upper middle class, well-educated, health professionals, most of whom who were born before the atomic bomb–to which most of us do not belong.

Shift in demographics in past 50 years;
predicted shift in next 50 years

Although we did begin to realize that race and other characteristics might actually matter with regard to health (hence the existence of datasets with more diversity), we can’t really fault those early researchers for creating such lopsided datasets. At that point, not only was the US more white than it is now, scientific advances that would reveal more about how our genetic background might affect health had not yet been developed. We had not yet mapped the human genome; epigenetics (the study of the interaction between environmental inputs and the expression of genetic traits) was in its infancy, and biochemical individuality was little more than a glimmer in Roger Williams’ eye.

Socially, culturally, and I think, scientifically, we were all inclined to want to think that everyone was created equal, and this “equality” extended to how our health would be affected by food. Stephen Jay Gould’s 1981 book, The Mismeasure of Man, critiqued the notion that “the social and economic differences between human groups—primarily races, classes, and sexes—arise from inherited, inborn distinctions and that society, in this sense, is an accurate reflection of biology.” In the aftermath of the civil rights movement, with its embarrassingly racist behavior on the part of some representatives of the majority race and the heartbreaking violence over differences in something as superficial as skin color, it was patently unhip to suggest that racial differences were anything more than just skin deep.

But does that position still serve us now?

In the past 35 years, our population has become more diverse and nutrition science has become more nuanced—but our national nutrition recommendations have stayed exactly the same. The first government-endorsed dietary recommendations to prevent chronic disease were given to the US public in 1977. These Dietary Goals for Americans told us to reduce our intake of dietary saturated fat and cholesterol and increase our intake of dietary carbohydrates, especially grains and cereals in order to prevent obesity, diabetes, heart disease, cancer, and stroke.

Since 1980, the decreases in hypertension and serum cholesterol—health biomarkers—have been linked to Guidelines-directed dietary changes in the US population [1, 2, 3, 4].

“Age-adjusted mean Heart Disease Prevention Eating Index scores increased in both sexes during the past 2 decades, particularly driven by improvements in total grain, whole grain, total fat, saturated fatty acids, trans-fatty acids, and cholesterol intake.” [1]

However, with regard to the actual chronic diseases that the Dietary Guidelines were specifically created to prevent, the Dietary Guidelines have been a resounding failure. If public health officials are going to attribute victory on some fronts to Americans adopting dietary changes in line with the Guidelines, I’m not sure how to avoid the conclusion that they also played a part in the dramatic increases in obesity, diabetes, stroke, and congestive heart failure.

If the Dietary Guidelines are a failure, why have policy makers failed to change them?

It is not as if there is an overwhelming body of scientific evidence supporting the recommendations in the Guidelines. Their weak scientific underpinnings made the 1977 Dietary Goals controversial from the start. The American Society for Clinical Nutrition issued a report in 1979 that found little conclusive evidence for linking the consumption of fat, saturated fat, and cholesterol to heart disease and found potential risks in recommending a diet high in polyunsaturated fats [5]. Other experts warned of the possibility of far-reaching and unanticipated consequences that might arise from basing a one-size-fits-all dietary prescription on such preliminary and inconclusive data: “The evidence for assuming that benefits to be derived from the adoption of such universal dietary goals . . . is not conclusive and there is potential for harmful effects from a radical long-term dietary change as would occur through adoption of the proposed national goals” [6]. Are the alarming increases in obesity and diabetes examples of the “harmful effects” that were predicted? It does look that way. But at this point, at least one thing is clear: in the face of the deteriorating health of Americans and significant scientific evidence to the contrary, the USDA and HHS have continued to doggedly pursue a course of dietary recommendations that no reasonable assessment would determine to be effective.

But what does this have to do with race?

Maintaining the myth that a one-size diet approach works for everyone is fine if that one-size works for you—socially, financially, and in terms of health outcomes. The single positive health outcome associated with the Dietary Guidelines has been a decrease in heart attacks—but only for white people.

And if that one-size diet doesn’t fit in terms of health, if you end up with one of the other numerous adverse health effects that has increased in the past 35 years, if you’re a member of the mostly-white, well-educated, middle/upper-middle class demographic—you know, the one represented in the datasets that we continue to use as the backbone for our nutrition policy—you are likely to have the financial and social resources to eat differently from the Guideline recommendations should you choose to do so, to exercise as much as you need to, and to demand excellent healthcare if you get sick anyway. Even if you accept that these foods are Guidelines-recommended “healthy” foods, you are not stuck with the commodity crop-based processed foods for which our nutrition programs have become a convenient dumping ground.

In the meantime, low-income women, children, and minorities and older adults with limited incomes—you know, the exact population not represented in those datasets—remain the primary recipients of federal nutrition programs. Black, Hispanic, and American Indian kids are more likely to qualify for free or reduced-price school lunches; non-white participants make up 68% of the Special Supplemental Nutrition Program for Women, Infants, and Children enrollment. These groups have many fewer social, financial, and dietary options. If the food they’re given doesn’t lead to good health—and there is evidence that it does not—what other choices do they have?

When it comes to health outcomes in minorities and low-income populations, the “healthier” you eat, the less likely you are to actually be healthy. Among low-income children, “healthy eaters” were more likely to be obese than “less-healthy eaters,” despite similar amounts of sedentary screen time. Among low-income adults, “healthy eaters” were more likely to have health insurance, watch less television, and to not smoke. Yet the “healthy eaters” had the same rates of obesity as the “less-healthy heaters” and increased rates of diabetes, even after adjustment for age.

These associations don’t necessarily indicate a cause-effect relationship between healthy eating and health problems. But there are other indications that being a “healthy eater” according to US Dietary Guidelines does not result in good health. Despite adherence to “healthy eating patterns” as determined by the USDA Food Pyramid, African American children remain at higher risk for development of diabetes and prediabetic conditions, and African American adults gain weight at a faster pace than their Caucasian counterparts [7,8].

Adjusted 20-year mean weight change according to low or high Diet Quality Index (DQI) scores [8]

In this landmark study by Zamora et al, “healthy eaters” (with a high DQI) were compared to “less-healthy eaters” (with a low DQI). Everyone (age 18-30 at baseline) gained weight over time; the slowest gainers—white participants who were “healthy eaters”—still gained a pound a year. More importantly however, for blacks, being a “healthy eater” according to our current high-carbohydrate, low-fat recommendations actually resulted in more weight gain over time than being a “less healthy eater,” an outcome predicted by known differences in carbohydrate metabolism between blacks and whites [9].

Clearly, we need to expand our knowledge of how food and nutrients interact with different genetic backgrounds by specifically studying particular racial and ethnic subpopulations. Social equality does not negate small but significant differences in biology. But it won’t matter how much diversity we build into our study populations if the conclusions arrived at through science are discarded in favor of maintaining public health nutrition messages created when most human beings studied were of the adult, mostly white, mostly male variety.

Right now the racial demographics of the participants in an experimental trial or an observational study dataset doesn’t matter, and the reason it doesn’t is because the science doesn’t matter. What really matters? Maintaining a consistent public health nutrition message—regardless of its affect on the health of the population—that means never having to say you’re sorry for 35 years of failed nutritional guidance.

*ARIC – Atherosclerosis Risk In Communities (1987), 73% white; MESA – Multi Ethnic Study of Atherosclerosis (2000), 38% white, 28% African American, 12% Chinese, 22% Hispanic; CARDIA – Coronary Artery Risk Development in Young Adults (1985), 50% black, 50% white; SHS – Strong Heart Study (1988), 100% Native American; BWHS – Black Women’s Health Study(1995), 100% black women.

References:

1. Lee S, Harnack L, Jacobs DR Jr, Steffen LM, Luepker RV, Arnett DK. Trends in diet quality for coronary heart disease prevention between 1980-1982 and 2000-2002: The Minnesota Heart Survey. J Am Diet Assoc. 2007 Feb;107(2):213-22.

2. Hu FB, Stampfer MJ, Manson JE, Grodstein F, Colditz GA, Speizer FE, Willett WC. Trends in the incidence of coronary heart disease and changes in diet and lifestyle in women. N Engl J Med. 2000 Aug 24;343(8):530-7.

3. Fung TT, Chiuve SE, McCullough ML, Rexrode KM, Logroscino G, Hu FB. Adherence to a DASH-style diet and risk of coronary heart disease and stroke in women. Arch Intern Med. 2008 Apr 14;168(7):713-20. Erratum in: Arch Intern Med. 2008 Jun 23;168(12):1276.

4. Briefel RR, Johnson CL. Annu Rev Nutr. 2004;24:401-31. Secular trends in dietary intake in the United States.

5. Broad, WJ. NIH Deals Gingerly with Diet-Disease Link. Science, New Series, Vol. 204, No. 4398 (Jun. 15, 1979), pp. 1175-1178.

6. American Medical Association. Dietary goals for the United States: statement of The American Medical Association to the Select Committee on Nutrition and Human Needs, United States Senate. R I Med J. 1977 Dec;60(12):576-81.

7. Lindquist CH, Gower BA, Goran MI Role of dietary factors in ethnic differences in early risk of cardiovascular disease and type 2 diabetes. Am J Clin Nutr. 2000 Mar; 71(3):725-32.

8. Zamora D, Gordon-Larsen P, Jacobs DR Jr, Popkin BM. Diet quality and weight gain among black and white young adults: the Coronary Artery Risk Development in Young Adults (CARDIA) Study (1985-2005). American Journal of Clinical Nutrition. 2010 Oct;92(4):784-93.

9. Hite AH, Berkowitz VG, Berkowitz K. Low-carbohydrate diet review: shifting the paradigm. Nutr Clin Pract. 2011 Jun;26(3):300-8. Review.