Blog

Controversy over the new dietary guidelines

Yesterday I filmed a piece on Fox Business about the new dietary recommendations and the call to reduce meat consumption to improve health and the environment (I couldn't get the video to embed, but you can view it here).  I suppose I had at least a couple good points to make because the clip was featured for most of yesterday on the main web page for Fox News.  

One of the hosts mentioned a Cambridge study showing that vegetarians and vegans have substantially lower environmental impacts than meat-eating diets.  A written piece at foxnews.com about the recommendations also mentions the same study.  I'm not sure how representative that cited study is.  My own analysis suggests that vegetarians spend about the same amount on food as do meat eaters.  To the extent prices reflect resource use, that stat would suggest both diets are "using up" similar levels of "stuff."  I've also written on the argument that the grain fed to livestock is "wasted."

But, perhaps more importantly, what evidence is cited in the new report of the dietary guidelines committee?  The papers they cite seem to suggest small improvements in greenhouse gas (GHG) emissions and improved health outcomes (but more on that in a minute) from a move to vegetarian diet.  Here are some selected quotes of the review in Chapter 5 part D where quantitative impacts on environment were mentioned (note: there are many other cited studies, some of which suggest higher impacts).

“Peters et al. examined 42 different dietary patterns and land use in New York, with patterns ranging from low-fat, lacto-ovo vegetarian diets to high fat, meat-rich omnivorous diets . . . although meat increased land requirements, diets including meat could feed more people than some higher fat vegetarian-style diets”

and

“Aston et al. assessed a pattern that was modeled on a feasible UK population in which the proportion of vegetarians in the survey was doubled, and the remainder adopted a diet pattern consistent with the lowest category of red and processed meat (RPM) consumers. They found . . . the expected reduction in GHG for this diet was ~3 percent of current total carbon dioxide (CO2) emissions for agriculture. De Carvalho et al. also examined a high RPM dietary pattern with diet quality assessed using the Brazilian Healthy Eating Index.They found . . . that excessive meat intake was associated not only with poorer diet quality but also with increased projected GHG emissions (~ 4 percent total CO2 emitted by agriculture). ”

This one is most interesting references:

“a report from Heller and Keoleian suggests that an isocaloric shift from the average U.S. diet (at current U.S. per capita intake of 2,534 kcals/day from Loss-Adjusted Food Availability (LAFA) data) to a pattern that adheres to the 2010 Dietary Guidelines for Americans would result in a 12 percent increase in diet-related GHG emissions. This result was modified, however, by their finding that if Americans consumed the recommended pattern within the recommended calorie intake level of 2,000 kcal/day, there would be a 1 percent decrease in GHG emissions. ”

My take?  Eating too many calories likely has as much an impact on GHG as eating meat.  Reducing meat consumption would lower GHG emissions, but I would characterize the effects as "small" (3 to 4% of the GHG emissions from agriculture, or likely less than 1% of the total of all GHG emissions), particularly if people move toward pork and poultry, which have far fewer GHG emissions than ruminants like cattle.  Moreover, if we want to improve environmental impacts of livestock production, I think we're likely to get a bigger bang for our buck by improving productivity and researching new ways to reduce impacts than we will be cajoling people to eat less meat (see this paper on the reduction in environmental impact of beef production brought about over the past 40 years due to technological advancement).

What about the health impacts of meat consumption?  It is true that many observational, epidemiological studies show a correlation between red meat eating and adverse health outcomes (interestingly there is a fair amount of overlap on the authors of the dietary studies and the environmental studies on meat eating).  But, this is a pretty weak form of evidence, and much of this work reminds of the kinds of regression analyses done in the 1980s and 90s in economics before the so-called "credibility revolution." 

There have been many, many books written on the topic of whether meat eating is good or bad for you, and I won't try to adjudicate them all here.  However, I will point you to this really interesting exchange (see the comments section) on Marion Nestle's website where she mentions the new guidelines and takes a swipe at Nina Teicholz's book, Big Fat Surprise.  Nina responds, as do her critics.  

New Dietary Guidelines

The federal committee that makes dietary guidelines and recommendations has just released their newest report.  As expected, they've incorporated "sustainability" objectives and have recommended a move away from meat eating.  I've previously commented on the the problem with a single committee making both nutritional and sustainability recommendations, and I had a piece in the Wall Street Journal on environmental impacts of meat production.   Now we can take a look at what's actually been proposed.

Here's one tidbit from a Washington Post summary on the issue.

““We’re not saying that people need to become vegans,” said Miriam Nelson, a professor at Tufts University and one of the committee’s members. “But we are saying that people need to eat less meat.”

The panel’s findings, which were released to the public in the form on a 572 page report this afternoon, specifically recommend that Americans be kinder to the environment by eating more plant-based foods and fewer animal-based foods. The panel is confident that the country can align both health goals and environmental aims, but warns that the U.S. diet, as currently constructed, could improve.”

Other conservative news sources point to some pretty heavy handed portions of the report.  The Dietary Guidelines Advisory Committee (DGAC):  

“called for diet and weight management interventions by “trained interventionists” in healthcare settings, community locations, and worksites.”

"Interventionists" is the right word here, but rarely are interventionists so forthcoming in their intentions.They also want to tax foods, limit speech, and monitor TV use.   

“DGAC also called for policy interventions to “reduce unhealthy options,” limit access to high calorie foods in public buildings, “limit the exposure” of advertisements for junk food, a soda tax, and taxing high sugar and salt items and dessert.

“Align nutritional and agricultural policies with Dietary Guidelines recommendations and make broad policy changes to transform the food system so as to promote population health, including the use of economic and taxing policies to encourage the production and consumption of healthy foods and to reduce unhealthy foods,” its report read.

“For example, earmark tax revenues from sugar-sweetened beverages, snack foods and desserts high in calories, added sugars, or sodium, and other less healthy foods for nutrition education initiatives and obesity prevention programs.”

The amount of sedentary time Americans spend in front of computers and TV sets is also a concern to the federal panel.”

If you think this is a one-off isolated example, you haven't been paying attention.

Food Demand Survey (FooDS) - November 2014

The latest edition of our Food Demand Survey (FooDS) is now out.

This month, consumer willingness-to-pay (WTP) for all food products (except steak, which was essentially unchanged) was up relative to October.  

Consumers continue to expect higher meat prices in the coming month (but not quite as much as last month).  Planned purchases of chicken were up relative to last month.

Three new ad hoc questions were added to the survey this month. Given the recent WTO ruling on the US mandatory country of origin labeling law (COOL) (see some discussion of the issues here), several questions were added to gauge consumers' knowledge and perceptions of different meat origin labels (thanks to Glynn Tonsor at K-State who provided suggestions on the questions).  

The first question asked: “Which of the following are grocery stores required by law to label for fresh meat products?” Participants were shown seven issues and were asked to select “required”,” not required”, or “I don’t know”, for each issue.  

64% of respondents believe nutritional content information is required to be labeled by law.  Over a third (39%) thought there was mandatory labeling for use of hormones.  For the remaining five issues, the plurality of consumers chose “I don’t know.”  This includes the three issues related to MCOOL.  About 40% of consumers did not know whether grocery stores required to label where an animal was born, raised, or slaughtered.  More consumers than not thought grocery stores were not required to label such origin information.  Only 22% of consumers thought grocery stores were required to label where an animal was born.   

Secondly, (and only after answering the preceding question), participants were asked: “What portion of pork products consumed in the United States is covered by current mandatory country of origin labeling laws?” The plurality, 23.79% of participants, responded saying that 40% to 59% of pork products consumed in the United Sates is covered under mandatory country of origin (COOL) laws.  17% though no pork products were required to be labeled, and about 12% though all pork products were required to be labeled.

he third question pertains to consumer’s willingness-to-pay for a 12oz boneless rib eye beef steak dependent on the country of origin. Respondents were randomly assigned to one of four groups that differed in the label given to the ribeye steak.  On fourth of participants were asked: “ What is the most you would be willing to pay for a 12oz boneless rib eye beef steak that was labelled as: Born, Raised, and Slaughtered in the U.S.?”  Other respondents answered similar questions except the labels were changed to: Born in Canada, Raised and Slaughtered in U.S.; Born and Raised in Canada, Slaughtered in the U.S.; or Product of Canada and the U.S.  Respondents answered by clicking a response category with a range of dollar values such as, $0, $0.01 to $2.99, . . ., $13.00 to $15.99, $16 or more.  Answers were used to estimate the mean WTP for each of the four groups.

Results indicate consumers valued beef that was born or born and raised in Canada $0.89 and $1.05 less, respectively, than beef that was born, raised, and slaughtered in the U.S.  Consumers do not distinguish between beef born in Canada and born and raised in Canada; the difference in WTP for these two labels ($6.11 vs. $5.95) is not statistically different.  Mean WTP for the label “product of Canada and the U.S.”, $6.55,  is higher than the other labels that mentioned Canada and only $0.45 lower than “Born, Raised and Slaughtered in the U.S.”, a difference that is not statistically different.