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!”

Calories? Again? Already?

Are we not sick of this subject already?

There have been some excellent articles and lots of “food for thought” on this topic recently.

Robb Dunn did a guest post at Scientific American about “The Hidden Truths About Calories,” which—to summarize in a way that does no justice to the article at all—basically boils down to the fact that most of the hidden truths about calories are so hidden we simply don’t know much about them at all. (I second this: Why Calories Count Fo’ Shizzle.)

Go Kaleo has a great post on this topic called “Putting the (Calorie) Pieces Together.” 

And Regina Wilshire has a puzzle for us at Weight of the Evidence called “Working Through A Stall.” 

Sooooooo – do calories in general matter, or is only the “kinds” of calories (i.e. the “good” kind vs the “bad” kind) that matter?

I think Go Kaleo said it very well: “All that black and white thinking has got people believing a false dilemma: It’s EITHER ‘calories in vs. calories out’ OR ‘the kind of calories you eat’ that matters!” She’s right in saying that it is a false dichotomy.

Neither approach comes close to acknowledging the complex interplay of factors that is human metabolism. I’m down on the calories in/calories out paradigm because it is so limited in scope, but I am equally down on any paradigm that says they don’t matter at all.

There are far too many unknowns about how the energy content of the food we eat interacts with the energy needs of our bodies to insist upon a singular health-maintenance paradigm based on “calories in, calories out.” At the same time, there are far too many unknowns about insulin metabolism (we currently don’t even have agreed-upon ways to measure and discuss insulin dysregulation) to create a new singular health-maintenance paradigm based on “fat in, carbohydrates out.”

One thing that complicates the picture is that we equate the metabolic situation that causes fat gain with the metabolic situation that will induce fat loss. My understanding of the biochemistry is that there are two necessary aspects to weight gain: excess calories to store (although we seldom know how to measure or even estimate what we mean by “excess”) and the insulin signal that provides the mechanism for storage to take place. Remove one of these factors—again with the caveat that we have a limited understanding of what “excess calories” means—and you won’t have weight gain.

Weight loss may be a different matter entirely. For weight loss to take place, we have to figure out NOT ONLY how to not create a metabolic situation where these two factors are at play, we also have to figure out how to convince our body to reverse the fat-storage process. This may involve processes which go beyond just one eliminating insulin-stimulating carbohydrate foods because—unless someone has Type 1 diabetes—some basal levels of insulin (and we may or may not know what they are or if they are “normal” or how that matters) are always present. This may also involve processes which go beyond just eliminating “excess” calories because, as I hope I’ve made clear, we don’t really even know what that means.

Some people can reduce overall calorie intake and lose weight (this usually also involves a lowering of carbohydrate foods that stimulate insulin release) ; some people can just reduce their carbohydrate food intake  and lose weight (this usually also involves lowering calories available for storage); some people have to do both–deliberately and carefully—in order to lose weight. The trick is how to do this without

  1. inducing willpower-withering hunger pangs
  2. depriving the body of essential nutrition
  3. creating other metabolically-unfortunate side effects/consequences.

The answer will not be the same for everyone. Reducing the number of nutritionally-empty carbohydrates gets at both the calorie and the carbohydrate issue–so that’s sort of a no-brainer, but carbs and calories are not all that matter.

Like what?

Metabolism matters. Nourishment matters. Information signaling—provided by your body’s encounters with the environment, including food encounters–matters.

Do calories affect these things? YES!!! Do carbs affect these things? YES!!! Are there about a bazillion other things that affect these things? YES!!!

When the clinic doors at the Duke Lifestyle Medicine Clinic open, the first two patients through those doors were both very much alike and radically different.

Both were “obese” adult white males, but that’s about where the resemblance ended. One gentleman, who was almost as big around as he was tall, was actually pretty healthy. Most, if not all, of what we think of as meaningful or predictive health biomarkers (blood pressure, cholesterol, glucose, etc) were normal. His problems were primarily orthopedic; i.e. his weight was impacting his hip and knee joints.

The other gentleman was far less obese, but his weight (as you may guess) was concentrated in his abdomen, his predictive health biomarkers were in the toilet, and he had a bag of prescriptions meant to normalize those biomarkers to prove it.

I (now) think of the first gentleman as having “simple” obesity and the second gentleman as having “metabolic” obesity. Such fat patterning has also been referred to as gynoid obesity (“pear”) and android (“apple”) obesity, and the different health consequences of each have been recognized, but even these differences are over-simplified concepts.

Android obesity (Gentleman #2) has been associated with excess insulin and with more metabolic derangement than gynoid obesity. It has been fairly well explained at this point that, aside from its role as a fat storage mechanism, excess insulin causes other metabolic problems.*

Is gynoid obesity (Gentleman #1) primarily associated with “excess” calories or “excess” storage of calories, rather than insulin dysregulation? We don’t know. Can “excess” calories cause other problems besides those leading to fat storage? We don’t know that either. One of the problems with asking these questions is—again—how we define “excess.”

Either way, the next step is to recognize that how we address different types of obesity may also need to be different. One type of obesity may be best addressed by a focus on reducing carbohydrate intake. The other type could be addressed by a focus on decreasing calories in and increasing calories out—however you want to do that. (As above, either approach involves some aspects of the other.)

But even differentiating dietary approaches based on fat-patterning must acknowledge that if there is a spectrum—with simple obesity on one end and metabolic obesity on the other—that any individual can be located anywhere along that spectrum and thus a combination of approaches would have to be used to address the needs of the individual, which may need to go beyond both carbs and calories.

It is crucial to remember that our bodies not really designed to either “gain”or “lose” weight, but to respond to our environment by small shifts in– up-regulating and down-regulating—the production of proteins, enzymes, and other biomolecules to meet the pressures of the environment. We are adapted to adapt. Food is one of the primary signals our bodies get about our environment. Food lets the body know what the conditions are like “out there” so that we can make appropriate adjustments “in here.” These adjustments, we know now, can be passed on from one generation to the next, so that our offspring are also prepared for what is “out there.”

What the body is looking for—all the time, without exception—is essential nourishment and adequate energy (and again our definition of “adequate” is as problematic as our definition of “excess”).  Note to paleo-thinking readers:  the origins of the paleo diet emphasize acquiring essential nutrition, rather than forbidding non-essential foods. This point may be the most important aspect of ancestral nutrition. (And thanks to Katherine Morrison for calling this to my attention.)

An eating pattern that conveys to our body that the environment is lacking in either of these things is going to result in metabolic adjustments to this information. What the adjustment looks like is going to depend on genetic factors (What food environment were your ancestors adapted to?), and epigenetic factors (Did you have an adequately-nourished mom?), and previous adaptive adjustments (Does your body regularly have to respond to caloric highs or lows? to regular bouts of intense energy expenditure? to reduced nutrition?), in addition to those other bazillion things we don’t know about yet.

So what are we going to do about it? I am so glad you asked. I’ve been trying to work my way to a blog post about n of 1, or individualized nutrition, for weeks now. I think I’m about there.

*See the work of Gerald Reaven and Wenhong Cao, for example.

Calories in, Calories out, Would You Please Go Now!

Ah, calories! Let me count the ways . . . that calorie-counting is a limited, grossly over-simplified, and ultimately highly unproductive way of addressing weight or health.

According to some, the key to health and a healthy weight is making sure your calories in = calories out. This is called being “in energy balance,” and, according to the USDA 2010 Dietary Guidelines, this is what most Americans are “out of.” We are fat because we eat more calories than we need—whatever that means. And the only way to NOT be fat is to “eat less and move more.”

Sounds simple enough. So why doesn’t it seem to work all that well?

Let’s start with the basics:

  • When a person decreases their “energy in,” that person’s “energy out” also goes down. For example, take Ancel Keys’ early starvation experiments.

  • When a person increases their “energy out,” that person’s “energy in” goes up. For example, take my 6’7″ basketball- & soccer-playing nephew out for dinner.


[Shameless Auntie plug: check out his latest endeavor, “Kicking across Carolina]

Eating less and moving more is like breathing underwater: not impossible, but somewhat awkward and unnatural. Some turtles can breathe underwater through their butts; some people can eat less and move more. For a lot of us, we are as likely to be as successful at the former as we are at the latter.


Turtles can, can you?

What? you say. But it’s SO obvious. People who eat less, weigh less; how much simpler could it be?

Except that we don’t really have a lot of data that demonstrates that this is the case. Oddly enough, this is a cross-cultural, age-independent, apparently universal, problem.

For example, for these American Indians, higher BMI is associated with lower calorie intake.


From: Xu J, Eilat-Adar S, Loria C, et al. Dietary fat intake and risk of coronary heart disease: the Strong Heart Study. Am J Clin Nutr. 2006 Oct;84(4):894-902.

In this Mediterranean population, higher BMI is associated with lower calorie intake.


From: Casas-Agustench P, Bulló M, Ros E, Basora J, Salas-Salvadó J; Nureta-PREDIMED investigators. Cross-sectional association of nut intake with adiposity in a Mediterranean population. Nutr Metab Cardiovasc Dis. 2011 Jul;21(7):518-25. Epub 2010 Mar 9.

In these kids, higher BMI is associated with lower calorie intake.


From: Qureshi MM, Singer MR, Moore LL. A cross-sectional study of food group intake and C-reactive protein among children. Nutr Metab (Lond). 2009 Oct 12;6:40.

Yeah, in these kids too.


The trend continues as kids become teenagers. Strangely, the teens who move more, eat more; the teens who move less, eat less. And, surprise, higher BMI is associated with lower calorie intake. Hmmm.


From: Patrick K, Norman GJ, Calfas KJ, et al. Diet, physical activity, and sedentary behaviors as risk factors for overweight in adolescence. Arch Pediatr Adolesc Med. 2004 Apr;158(4):385-90.

As you may be aware, some researchers do have an explanation for this phenomenon: Fat people lie. That’s certainly a much more convenient explanation than examining the possibility that there is more to nutrition metabolism than “calories in, calories out.

Sadly, this lying stuff apparently starts young. In this study, the researchers concluded that the 9-year old girls under investigation are apparently lying about how much they eat:

“Importantly, this study found that the positive association between energy intake and adiposity was observed only after excluding implausible energy intake reports, but not in the total sample which included implausible reporters, the majority of which were overweight children who under-reported energy intake.”

This means there is no association between calories and overweight in the general sample. An association is only found if the researchers exclude “implausible” intakes of overweight children who “under-report” what they eat. The researchers determine which intake levels were “implausible” because they know how to calculate how much fat kids are supposed to be eating:

“Physiologically plausible reports of energy intake were determined by comparing reported energy intake with predicted energy requirements.”

In other words, if the chubby little girls don’t eat as much as the researchers think they should be eating, as calculated using formulas that are notoriously inaccurate, then the conclusion is that they (the girls, not the researchers) are lying.

Luckily, the folks at the USDA are totally on top of this issue and can give us a clear explanation of what is going on:

“One would expect to find a strong positive association between caloric intake and a measure of body fatness, such as the body mass index (BMI).”

Yes, one would, if one thought that all that really matters is how many calories go in and how many calories go out.

“However, nutrition studies using self-reported food intake data, such as the CSFII data, have failed to find such an association, . . . ”

Y’don’t say? Hmmm. Wonder why that could be? Maybe nutrition is more complicated than a simple energy balance equation?

” . . . primarily because overweight persons tend to underreport intakes to a greater degree than healthy weight persons.”

Oh right, I forgot. So, they’re all lying? Native Americans, people in other countries, old people, young kids (or maybe their parents)?

Also, at any given time, overweight persons may be on weight-loss diets. ” [emphasis mine]

Ohhh.  That might help explain things. In other words, fat people either do not have the moral fortitude to be honest with themselves or anyone else about how much they eat, or they are—bravely, in the face of ridiculous odd against them—reducing the number of calories they eat.

In a study examining the association between calorie intake and BMI in women who are dieting, the investigators found, big surprise, an inverse association between BMI and calories (Ballard-Barbash R, Graubard I, Krebs-Smith SM, Schatzkin A, Thompson FE. Contribution of dieting to the inverse association between energy intake and body mass index. Eur J Clin Nutr. 1996 Feb;50(2):98-106.).

In other words, higher BMI is associated with lower calorie intake.  The researchers conclude that:

“Intermittent energy restriction appeared to be a significant factor in the reduced energy intake reported among overweight women in this sample.”  

The women aren’t lying; they’re dieting. Maybe they’re doing both!

Two-thirds of Americans are overweight or obese.  Apparently, two-thirds of Americans are either lying or dieting, or maybe both.

If you are a lying fat person, we can’t really draw any reasonable conclusions from the epidemiological data we gather about your eating habits. Furthermore, weight loss programs based on “calories in, calories out” are not likely to help you because you lie about what you eat anyway.

If you are a dieting fat person, we can’t really draw any reasonable conclusions from the epidemiological data we gather about your eating habits. Furthermore, weight loss programs based on “calories in, calories out” are not likely to help you because conventional weight loss programs are not likely to help anyone.

It is just a thought, but perhaps is it time to think about whether there are other things—besides normal human metabolism–that may affect “energy balance.” Quick brainstorm list off the top of my head:

  • genetics
  • epigenetics
  • environmental toxins
  • hormonal status
  • lifestage
  • disease state
  • medications
  • infection/inflammation
  • sleep patterns
  • stress
  • gut flora
  • and last but not least, the food you eat

What? you say. The food we eat?

If you want to be obsessed about calories going in and out, it makes sense to figure out which foods might cause fewer calories to go in and which food might cause more calories to go out. We don’t have all the answers—and it is my personal perspective that individual response is what matters most—but, here are a few clues:

In this study, participants who ate eggs for breakfast (with no other deliberate dietary changes) consumed 400 fewer calories over the course of the day than the participants who ate bagels, i.e. calories in went down.


From: Ratliff J, Leite JO, de Ogburn R, Puglisi MJ, VanHeest J, Fernandez ML. Consuming eggs for breakfast influenced plasma glucose and ghrelin, while reducing energy intake during the next 24 hours in adult men. Nutr Res. 2010 Feb;30(2):96-103.

In this study, when participants consumed a diet with reduced carbs and increased fat, resting and total energy expenditure tended to go up compared to when the same participants consumed diets with higher carb and lower fat content, i.e. calories out went up.


From: Ebbeling CB, Swain JF, Feldman HA, Wong WW, Hachey DL, Garcia-Lago E, Ludwig DS. Effects of dietary composition on energy expenditure during weight-lossmaintenance. JAMA. 2012 Jun 27;307(24):2627-34.

So, strangely enough, simply by choosing foods that are specifically NOT recommended in the current low-fat, low-cholesterol, high-carbohydrate diet promoted by the USDA/HHS, you may be able to alter your “energy balance” so that there are fewer calories coming in and more calories going out, without having to change anything else.

It’s time to quit condemning 9-year-old girls to a lifetime of hunger and frustration with “calories in, calories out” dieting, or accusations about them lying about what they eat, or both.

To paraphrase the immortal words of Dr. Suess:

“Calories in, calories out” will you please go now!

The time has come.

The time is now.

Just go.

Go.

Go!

I don’t care how.

“Calories in, calories out”

I don’t care how.

“Calories in, calories out”

Will you please

GO NOW!

Next up: The Mobius strip of policy & the future of nutrition

Big Fat Liars

Since 1980, Americans have gotten progressively more lazy and gluttonous. As if this were not bad enough, apparently about 2/3 of the population—the fat 2/3 of the population—have also become unrepentant liars. Although we have no way to explain this precipitous decline in the moral fiber of Americans, we know it must be happening because Americans seem to be getting fatter and fatter even though many of these fat Americans report that they are not eating more calories than their normal-weight, honest, hard-working counterparts.

It seems that when we gave the USDA and HHS the responsibility for determining what food was healthy for each of as individuals, Government Approved Nutrition Experts also developed a magical ability (in Nutrition, we love magic!) to tell the difference between what was Truly True and what was a Big Fat Lie. Here’s a response I got to a food record assignment during an introductory Nutrition course:

Question: What are your barriers to meeting the MyPyramid recommendations? (In other words, what might prevent you from consuming the recommended amount of each food group?)
My answer (after describing the low-carb diet that I used to lose weight and improve my migraines):I have a history of glucose intolerance and overweight/obesity.  Past a certain point of consumption, carbohydrates make me gain weight, raise my blood     pressure, reduce my energy levels, give me migraines, make my blood sugar wonky, and leave me hungry and cranky.  I stick to fiber-rich, nutrient-dense, non-starchy vegetables for my carbohydrates, although I do eat fruit when it is in season locally.
Instructor’s response (I am not making this up):  It is actually the total calories that make you gain weight, not the carbohydrates.  The high fat intake would be more detrimental than the whole grains and fiber rich vegetables.  Refined carbohydrates would cause the symptoms you describe but using whole grains and high fiber fruits and vegetables should not do so.  You need carbohydrate for your brain to function.  It does not function on fat and protein calories.  In fact eating a low carbohydrate diet such as you describe would make you tired, give you migraines, make you hungry and cranky.

Silly me! Of course the Nutrition Expert knows what REALLY caused my weight gain and migraines. Obviously the lack of carbohydrate to my brain prevented me from realizing her innate superiority at understanding and interpreting my own personal experiences. Either that or I’m just a Big Fat Liar.

Let me introduce you to another Nutrition Expert with the magical ability to tell Truth from Fat People Fiction–Michael Pollan:

Consider: When the study began, the average participant weighed in at 170 pounds and claimed to be eating 1,800 calories a day. It would take an unusual metabolism to maintain that weight on so little food. And it would take an even freakier metabolism to drop only one or two pounds after getting down to a diet of 1,400 to 1,500 calories a day — as the women on the “low-fat” regimen claimed to have done. Sorry, ladies, but I just don’t buy it. (Pollan M. Unhappy Meals)

The women in the Women’s Health Initiative (to which Pollan refers) are: Female. Post-menopausal. Overweight. From my experience at the Duke Lifestyle Medicine Clinic (director, Dr. Eric Westman), just about any woman who met those three criteria exhibited this sort of “freaky metabolism.” Not only is it possible for a woman in that hormonal situation to maintain her weight on 1800 kcals/day, it may be absolutely impossible for her to lose weight on 1400-1500 kcals/day—if she’s eating foods that enhance fat storage and prevent fat utilization (carbs, I’m lookin’ at you). In fact, not only did I see many other women like this in clinic, I stopped losing weight myself (at 185 pounds) eating 1200-1500 calories a day—and I wasn’t even postmenopausal. But then, at that point, I wasn’t a Nutrition Expert either. Not like Michael Pollan.

I always wonder why Mr. Investigative Journalist/Nutrition Expert Pollan didn’t go out find a few real live overweight, post-menopausal women and ask them what their personal experiences were with weight loss instead of simply discounting the experiences—and calling into question the humanity and integrity—of the “ladies” in the study. Oh wait, if the ladies he interviews are overweight, they’d all just LIE to him!

Anyway, why ask a real person, when you have Science on your side? Here’s a nutrition textbook explaination just how it is that we KNOW fat people lie:

Another approach to check for underreporting is to compare reported usual energy intake with resting energy expenditure calculated using various equations . . . If a subject’s reported usual energy intake is <1.2 times his or her calculated REE, underreporting of energy, and therefore nutrient, intake is highly likely. (Lee & Nieman, 2007).

In other words, if fat people don’t eat as much as we think they should be eating according to calculations that are known to be notoriously inaccurate, they must be “underreporting” (this is a complicated Scientific Term that means “lying about”) how much they eat. In my current Obesity class at UNC, Dr. Andrew Swick has confirmed—through evaluations done in a metabolic chamber—that some overweight/obese women have energy requirements as low as 1200-1300 calories (hmm, “freaky metabolism” maybe?),  requirements that would be far below “calculated requirements” referred to above. Dr. Swick pointed out to us that some fat people don’t, in fact, eat that much food.

But we should never let reality stand in the way of Government Approved Nutrition Information (code name: GAIN). Our good buddies at the USDA and HHS prepared this helpful chart for the 2010 Dietary Guidelines Advisory Committee Report to show how many calories Americans are consuming compared to the recommended ranges:

The vertical lines are recommended calorie ranges; the pink triangles are the average calorie intake in each group. Caloric intake appears to be within the recommended range for all age levels; adult women in general seem to be consuming at the very low end of their caloric range, about as many calories as a preschool male. That’s right, women over the age of 50 eat, on average, about as much food as 2-5 year old boys.

This must be more of that “freaky metabolism” thing to which Mr. Pollan refers. Or—wait—maybe they are all just LYING (the old ladies, not the little boys): the 2010 Dietary Guidelines for Americans go on to say, “While these estimates do not appear to be excessive, the numbers are difficult to interpret because survey respondents, especially individuals who are overweight or obese, often underreport dietary intake.” And we know what “underreport” means, right?

According the USDA and HHS, Americans aren’t fat because they are told to eat foods they don’t need to eat, Americans are fat because they eat too much–and then lie about it.

So, let me sum this up for the folks at home:

Fat people say that they don’t eat more calories than their normal weight (and apparently morally superior) counterparts.  But we know they are lying because Nutrition Experts—like Michael Pollan—KNOW how much fat people eat should be eating (i.e. A LOT of food—otherwise, golly, they wouldn’t be so darn fat).  ).  He KNOWS this because he’s a Nutrition Expert and because we have scientists who have calculations that tell us how much fat people are supposed to eat (i.e. A LOT) so when fat people say they don’t each as much as scientists think they eat (i.e. A LOT), well then, the only possible explanation for that is that the fat people are LYING!  And if that’s not enough evidence for you (and really, it should be), you can absolutely believe that that fat people LIE about how much they eat because the Government says they do.

And the government never lies.

References:

Lee RD and Nieman DC. Nutritional Assessment, 4th ed. Boston: McGraw Hill, 2007.

Pollan M. Unhappy Meals. The New York Times Magazine, January 28, 2007

U.S. Department of Agriculture and U.S. Department of Health and Human Services. Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010. June 15, 2010.

U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2010. http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm Accessed January 31, 2010.

If Nutrition Experts Built Bridges–

If you are an engineer, your plan—bottom line, no fudging about—has to WORK. All. The. Time. It’s what we expect from engineers.

On the other hand, if you are a Government-Approved Nutrition Expert, your plan doesn’t have to work AT ALL.

Which may be why we don’t let Nutrition Experts build bridges.

To ensure a more impressive rate of success, engineers tend to build their bridges and elevators based on a few mysterious but fundamental concepts like physics (or as we say around here, fweezix). Now, to paraphrase Barbie, I understand that physics is TOUGH. But it is also, well, insurmountably the real deal, and anything that defies the laws of physics is generally—for lack of a better word—considered to be magic.

Now, from my biochemistry classes, it looks like the principles of nutrition are built on chemistry, and the principles of chemistry are built on—you guessed it!—politics fweezix. But when I step across the hall to my public health classes, then the principles of nutrition are based on the Dietary Guidelines, which—as they tend to be in defiance of the laws of physics—I guess must be magic!

Despite the rockin’ groove, I’m not sure that I believe in magic.

But Calories In = Calories out is not magic, it’s physics, right? It seems indisputable—a veritable law of thermodynamics—that if you consume fewer calories than you expend, you will lose weight. Conversely, if you consume more calories than you expend, you will gain weight. Duh.

Sometimes when things aren’t working (i.e. major bridge oopie ), we get a glimpse of the realities of the physics behind the system. Let’s take a look at a category of individuals that do lose weight easily—too easily: Type 1 diabetics. A type 1 diabetic could eat 5000 calories a day, never move a muscle, and still lose weight (for the record: this is not a good thing). What happens to those calories? Why don’t they get stored as fat (hello? calories IN?) A type 1 diabetic can’t store them as fat. Why not? No insulin. Without insulin, the body cannot store energy at all. Type I diabetics must be given insulin or they literally waste away. It’s not because they try harder; it’s because of fweezix.

What this means is that it can’t just be the amount of calories that we are consuming, but also the source. And in the case of unnecessary carbohydrates in the diet, it’s likely to be both. The increase in caloric intake we’ve seen in the past 30 years has come almost entirely from industrialized carbohydrate food products—subsidized and endorsed by the USDA.

Would obesity rates have skyrocketed without the Guidelines prompting Americans to eat fewer animal products—especially meat and eggs which contain Very Scary saturated fat and cholesterol—and more whole grain cereal products? We’ll never know. But physics does tell us that carbohydrate foods have particular qualities that affect fat storage and metabolism, specifically: “A high carbohydrate meal stimulates the production of insulin. Insulin inhibits the body’s ability to use fat for energy and stimulates the uptake of fat and its storage as triacylglycerol” (Campbell & Farrell, 2009). That’s straight from my biochemistry textbook.

Now I don’t care if you eat carbs or not. Some of my best friends are carbs. But can we stop pretending that somehow—magically—there’s no relationship between the two figures above?

Apparently we can’t. According to many Nutrition Experts, including Marion Nestle, our low-fat Dietary Guidelines can be blamed only in that they do not do more to “address caloric intake, portion size, inactivity, and other contributors to obesity” (Woolf & Nestle, 2008). Notice that “caloric intake,” “portion size” and “inactivity” are all things that are our fault—in contrast to a diet recommendation of mostly carbohydrates, something the USDA and HHS are responsible for. In other words, if chubby little Americans can’t “achieve energy balance” by eating less and exercising more, it’s not because the Guidelines aren’t helping us, it’s because we are simply not trying hard enough.

(True Confession: I mostly just wanted to draw that cartoon.)

Should we reduce our calories? Maybe not a bad idea for some folks.

What kind of calories should we reduce? Ask an engineer. Unless you believe in magic . . .

References:

Campbell MK, Farrell SO. Biochemistry, 6th ed. United States: Thomson, 2009. p. 730.

Centers for Disease Control and Prevention (CDC). Trends in intake of energy and macronutrients–United States, 1971-2000. Morbidity and Mortality Weekly Report. 2004 Feb 6;53(4):80-2.

Woolf SH, Nestle M. Do dietary guidelines explain the obesity epidemic? American Journal of Preventive Medicine. 2008 Mar;34(3):263-5.

Public Health Nutrition’s Epic Fail

Mostly I just wanted to say “epic fail” because it embarrasses my kids, but then, they are always harshing on my mellow.

The stated goals of the US Dietary Guidelines are to promote health, reduce risk of chronic disease, and reduce the prevalence of overweight and obesity.

How’s that working for us?

First the good news. Cholesterol levels and hypertension have trended downwards since the creation of our first Dietary Guidelines.

It is possible that the changes in these risk factors reflect a trend that was already well underway when the Dietary Guidelines were written . . .

. . . although some folks like to attribute the changes to improvements in our eating habits (Hu et al 2000; Fung et al 2008). And btw, yes, they actually have improved with regards to the dietary recommendations set for in our Guidelines. Don’t believe me? You’re not alone. Here’s the data.

Soooooo . . . if our diets really have improved, and if those improvements have led to related improvements in some disease risk factors (because cholesterol levels and even blood pressure levels are not diseases in and of themselves, but markers—or risk factors—for other disease outcomes, like heart disease and stroke), let’s see how the Guidelines fared with regards to actual disease.

This trend is a little ironic in that cancer was, at first, one of the primary targets for nutrition reform. It was Senator George McGovern’s ire at the Department of Health, Education, and Welfare’s (now the Department of Health and Human Services) failure to aggressively pursue nutritional links to cancer that was at least part of the motivation behind giving the “lead” in nutrition to the USDA in 1977 (Eskridge 1978; Blackburn, Interview with Mark Hegsted). In fact the relationship between dietary fat and cancer had so little solid evidence behind it, the 2000 Dietary Guidelines Advisory Committee had this to say: “Because relationships between fat intake and cancer are inconclusive and currently under investigation, they are deleted.”

I guess we can then feel assured that the reason that the restrictions against fat and saturated fat are still in the Dietary Guidelines is because their relationship to heart disease isn’t inconclusive or “currently under investigation”? If that’s the case, somebody better tell these folks. So what did happen to heart disease as we lowered our red meat consumption and our egg intake, while we increase our intake of “heart-healthy” grains and vegetable oils?

Well, you’d think with all of that reduction in fat and saturated fat, plus the decrease in smoking, we’d be doing better here, but at least—well, at least for white people—the overall trend is down; for black folks, the overall trend is up.

Oops. Not so good.

Hmmm.

Oh. Well. This can’t be good. And of course, my favoritest graph of all:

I’m not sure, but it sorta kinda looks like the Dietary Guidelines haven’t really prevented much, if any, disease. Maybe we could get those guys at Harvard to take a closer look? I mean, looking at these trends—and using the language allowed with associations—you might say that the development and implementation of Dietary Guidelines for Americans is associated with a population-wide increase in the development of cancer, heart failure, stroke, diabetes, and overweight/obesity. Anyway, you might say that. I would never say that. I’m an RD.

Are there other explanations for these trends? Maybe. Maybe not.

It’s always a good idea to blame food manufacturers, but we have to remember that they pretty much supply what we demand. And in the past 30 years, what we’ve demanded is more “heart-healthy” grains, less saturated fat, and more Poofas. Yes, food manufacturers do help shape demand through advertising, but the Dietary Guidelines don’t have anything to do with that.

Oh yeah. That‘s so whack, it’s dope.

References:

Blackburn H. Interview with Mark Hegsted. “Washington—Dietary Guidelines.” Accessed January 24, 2011. http://www.foodpolitics.com/wp-content/uploads/Hegsted.pdf

Centers for Disease Control and Prevention (CDC). National Center for Health Statistics, Division of Health Interview Statistics, data from the National Health Interview Survey. http://www.cdc.gov/diabetes/statistics/prev/national/figpersons.htm. Accessed 15 August 2010.

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