In this three-part series, I will be evaluating some of the proposed dietary drivers of the obesity epidemic in the United States.
I decided to create this series to address claims that are made on the my forum, which are, quite frankly, at odds with the evidence. I hope that this blog post will contribute to putting some of these claims to rest.
In the first part of this series, I will be addressing a popular theory: that the obesity epidemic is driven by increasing consumption of wheat.
This claim is evidently at odds with the evidence–a huge amount of evidence. Here’s a few pieces of that evidence.
- Wheat consumption has decreased over the past fifteen years (United States Department of Agriculture):
- Yet, the percentage of obese adults has gone from 30.5 to 37.7% in the same period of time (United States Center for Disease Control):
It therefore follows that over the last 15 years, the consumption of wheat and the rise of obesity have been strongly INVERSELY correlated: wheat consumption has consistently gone down, while obesity has consistently gone up.
- But wait, there’s more. This decline in wheat consumption is, from historical perspective, even more marked (United States Department of Agriculture):
From 1935 levels, Americans’ consumption of wheat is down nearly 40 pounds per person per year.
- Yet, while the level of wheat consumption in the 1930s was higher than its peak in the ’90s, and much higher than that today, average BMI (and levels of obesity) was lower in the ’30s (Centre for Economic Policy Research, VOXEU):
(The highest line marks the 90th percentile, the lowest lowest line marks the 10th percentile, with all gradations in between.)
In other words, the historical record on obesity shows a trend in the opposite direction of this decrease in wheat consumption.
- To drive the point home, here is a graph of the rate of change in BMI, also charted in deciles:
Perhaps the most remarkable feature of this graph is the inflection point that occurs between 1945 and 1950, just following World War 2, when the rate of increase in BMI among deciles–especially the upper 2-4 deciles–begins to spread markedly, and the rate of increase in obesity accelerates dramatically. Relevant to the theory of wheat consumption-driven obesity epidemic, according to the information presented two graphs back, this inflection point occurs at precisely the same moment when wheat consumption per capita in the U.S. begins a marked, 3-decade-long decline.
So again, we see an inverse correlation between wheat consumption and obesity.
- There’s more evidence to contradict the case against wheat (at least in terms of the obesity epidemic). How does the United States compare to other countries? As the most obese developed country in the world, does the United States have the highest consumption, per capita, of wheat? Is it even in the upper tier of wheat consumption?
The United States, the most obese developed country in the world, actually has relatively low levels of wheat consumption, at least when compared to many other developed countries. Data from the World Bank:
|Australia||308.04 thousand metric tons||2004|
|Turkey||254.32 thousand metric tons||2004|
|Russia||246.79 thousand metric tons||2004|
|Canada||240.66 thousand metric tons||2004|
|Morocco||207.66 thousand metric tons||2004|
|Ukraine||204.95 thousand metric tons||2004|
|Algeria||195.75 thousand metric tons||2004|
|Iran||190.36 thousand metric tons||2004|
|Egypt||179.91 thousand metric tons||2004|
|Pakistan||120.85 thousand metric tons||2004|
|United States||113.4 thousand metric tons||2004|
|China||80.63 thousand metric tons||2004|
|India||62.13 thousand metric tons||2004|
|Brazil||54.07 thousand metric tons||2004|
|Japan||47.28 thousand metric tons||2004|
>>> Recent studies suggest that low carbohydrate diets appear to be safe and effective over the short term, but show no statistical differences from control diets with higher carbohydrate content and cannot be recommended as the default treatment for people with type 2 diabetes. >>>
In the future, every hospital admission and treatment program for a chronic disease will include comprehensive nutritional counseling and education and food preparation and practice in an on-site kitchen. Hospital cafeteria services will provide choice (i.e. they will serve sufficient healthy foods to provide for a healthy square meal) and send a very clear message about what high quality food means through the food they provide. Cafeteria services will not reinforce the messages of the processed food industry at the expense of patient health; cafeteria services will instead be just one more aspect of hospital nutrition education.
We’re not there yet.
The vast majority of hospitals still appeal to “consumer preference” in organizing and managing their food and nutrition services.
Since “consumer preference”, as shaped by processed food marketing, has led to the current epidemic of chronic disease, and since such preference apparently leads to the vast majority of hospital admissions, it should be obvious that while serving low-quality, processed foods and calling them healthy (as most hospitals do) serves to encourage revenue growth, it is at odds with the stated mission of hospitals in promoting the health of the community.
Hospitals can still take a page from hospitals that are doing things right. This hospital in Melbourne, Australia is moving in just that direction, by promoting healthy choices through a simple labeling system on sugary drinks. It’s one small step, but it’s an important one in moving toward the hospitals of the future.
Thanks to Megan Pfeffer for the article.
What percent of global greenhouse gas emissions is agriculture responsible for? I have heard low balling estimates as low as 9%. I have never read of such a low estimate for greenhouse gas emissions for agriculture. I have heard of much higher. So I decide to go on a little search, and compile a few of my findings.
EPA: 24%- “Agriculture, Forestry, and Other Land Use (24% of 2010 global greenhouse gas emissions): Greenhouse gas emissions from this sector come mostly from agriculture (cultivation of crops and livestock) and deforestation. This estimate does not include the CO2 that ecosystems remove from the atmosphere by sequestering carbon in biomass, dead organic matter, and soils, which offset approximately 20% of emissions from this sector.”
IPCC: 24% (probably same source as above)- “Agriculture, deforestation, and other land use changes have been the second-largest contributors whose emissions, including other GHGs, have reached 12 GtCO2eq/yr (low confidence), 24% of global GHG emissions in 2010.”
EPA: 9% (United States only)- “In 2014, greenhouse gas emissions from agriculture accounted for approximately 9 percent of total U.S. greenhouse gas emissions. Greenhouse gas emissions from agriculture have increased by approximately 11 percent since 1990. One driver for this increase has been the 54 percent growth in combined CH4 and N2O emissions from livestock manure management systems, reflecting the increased use of emission-intensive liquid systems over this time period. Emissions from agricultural soil management have also increased by about 5 percent since 1990. Emissions from other agricultural sources have either remained flat or changed by a relatively small amount since 1990.”
FAO: 14.5% (livestock only)- “Total emissions from global livestock: 7.1 Gigatonnes of Co2-equiv per year, representing 14.5 percent of all anthropogenic GHG emissions. This figure is in line FAO’s previous assessment, Livestock’s Long Shadow, published in 2006, although it is based on a much more detailed analysis and improved data sets. The two figures cannot be accurately compared, as reference periods and sources differ.”
Nature: up to 1/3 (global food system in its entirety)- “The global food system, from fertilizer manufacture to food storage and packaging, is responsible for up to one-third of all human-caused greenhouse-gas emissions, according to the latest figures from the Consultative Group on International Agricultural Research (CGIAR), a partnership of 15 research centres around the world.”
WRI: 13% (agriculture narrowly defined, excluding transport)- “Farms emitted 6 billion tonnes of GHGs in 2011, or about 13 percent of total global emissions. That makes the agricultural sector the world’s second-largest emitter, after the energy sector (which includes emissions from power generation and transport).”
“Livestock’s Long Shadow” (FAO): 18% (livestock only)- “Overall, livestock activities contribute an estimated 18% to total anthropogenic GHG emissions from five major sectors for GHG reporting: energy, industry, waste, land use, land use change, land use change and forestry (LULUCF) and agriculture.”
So as low as 13%, as high as one-third if you calculate in the cost of the entire food system (which probably makes more sense). The latter figure would possibly put the food system as the highest emitter of all sectors of the global economy.
If you know of something wrong with these figures, I would love to know.
As usual, the soda industry has pumped millions into a campaign to stop the Philadelphia soda tax from passing into law. But they will likely fail; the law is expected to pass tomorrow.
A few thoughts.
When someone says of taxes such as these, “but government should not tamper with the free market!” remember, that with sugary beverages, the government already has. The reason such beverages are so inexpensive is government subsidies, i.e. tampering with the market, in the first place.
Progressives, who understand that food environments have more of an impact on the health of the vast majority of people than does “willpower” (as evidenced by the past 50 years of mass dieting failure), obviously celebrate the law. But free marketeers should, too: the tax does not limit choice, but brings it in line with the market, which, as they say, they celebrate in the first place. Right?
Right now we subsidize soft drinks, and then apply a tax to remove the subsidy. But how about, rather than this rather perverse and contradictory set of policies, we remove the subsidies in the first place? I think progressives and free market cheerleaders could all come to the table and agree on that.
But until the federal government steps up the plate and assumes leadership for putting an end to our food-related health crisis (and healthcare spending, and economic and political crises by extension…), a tax seems like the next best thing.
Congratulations Philadelphia: for doing what most of our other leaders seem too afraid to do.
Do you purchase organic dairy products?
The Cornucopia Institute writes:
“The Horizon brand depends on giant CAFOs, milking thousands of cows each, for a large percentage of their production and that impacts the quality and nutritional value of all their products.”
For this and many other reasons, I am not sure I would consider Horizon “organic” in anything but name. They seem to treat their cows inhumanely, and they produce milk not much differently than do non-organic producers, i.e. the cows are often not pastured on grass.
That they can be organic in name is a testament to the corruption of the organic label. Horizon’s violations however go back well over a decade. A quick Google search will reveal this.
Buy Horizon if you want overpriced, industrially produced dairy.
For dairy, Organic Valley is a better bet and has a much better track record.
Marion Nestle is doing a casual review of the literature, tallying sponsor-funded research conclusions as favorable or unfavorable. Her results so far: of 142 industry-funded studies, 130 have been favorable to the sponsors, 12 unfavorable. See here.
This is only the latest of a long line of investigations that show, contrary to the insistence of those who seem to believe that all research should be considered equal regardless of the source, that funding source does affect research outcomes–whether because funders will only fund research that they believe will find favorable results (thus skewing the whole of the body of research literature, much like publication bias does) or because funding itself subtly alters any number of procedures, biasing the results (in effect, I believe that this is not much different than the former effect). In both cases, a body of literature is produced that systematically favors sponsors and thereby distorts our picture of reality. See studies here and here.
In order to correct this distortion of reality, which is a systemic fact even if it does not apply in every case, I believe it is both legitimate and necessary to criticize studies on the basis of their funding sources ALONE. It may be impossible to prove distortion in any individual case; but if the sum result of studies points to distortion, does this not cast a shadow on individual cases?