Photo by Alternative Heat.

The journal Nature recently had an interesting meta-analysis — or quantitative literature review — about yields from organic agriculture. It’s called “Organic farming is rarely enough,” and the accompanying summary says, “Conventional agriculture gives higher yields under most situations.” This is probably true.

Yet even environmentalists are overreacting to the study. A recent article by Bryan Walsh at TIME magazine’s Ecocentric blog is titled, “Why Organic Agriculture May Not Be So Sustainable.”

The evidence Walsh presents fails to support the headline, though the article does begin with two good points: Organic agriculture does often produce less food per acre (see the Nature article above). And environmentalists should care about efficiency. Getting more output for lower resource cost is good environmentalism.

Mostly, though, Walsh repeats common overstatements of the advantages of conventional agriculture. He writes, “Conventional industrial agriculture has become incredibly efficient on a simple land to food basis. Thanks to fertilizers, mechanization and irrigation, each American farmer feeds over 155 people worldwide.”

But environmentalists discussing conventional agriculture should also remember several key themes.

• Not all productive technology improves the environment. Many technologies used in conventional agriculture are designed to save labor, not to save land. In Walsh’s quote above, huge mechanized combines elevate the number of people fed per American farmer, but they make little difference to yields per unit of land (the key environmental issue addressed by the Nature study). From one sentence to the next, Walsh conflates food per American farmer with efficiency “on a simple land to food basis.”

• Yield is not the same as efficiency. Organic agriculture commonly requires a trade-off, giving up some yield and undertaking some additional labor and management cost in order to gain something of value for the producer and for the environment. Advocates for organic agriculture say the trade-off is efficient — getting the most output for the lowest resource cost when all environmental costs are accounted. Walsh’s first sentence boasts of the “efficiency” of industrial agriculture, but the following argument fails to support the boast.

• Producing more grain is not the same as feeding the world. Any time the high yields of U.S. corn production are mentioned, it should be noted that most U.S. corn goes to ethanol and animal feed. Walsh seems to think that Iowa corn farmers do well at feeding the most people possible for the least land, which is false. If the goal is to feed the world, then most of the calories produced in Iowa corn fields are squandered already, and this loss matters more than the organic yield penalty matters.

Most hard-headed, well-grounded advocates for organic agriculture already understand the yield tradeoffs, and they already value efficiency. For example, Rodale studies over the years have always claimed that lower chemical input costs offset modest yield differences — a claim that may be nearly consistent the new Nature study.

I have sometimes met beginning organic farmers who are dismissive of yields and efficiency. But I have never met an organic farmer who has been in business for five years and remains dismissive of yields and efficiency.

There is one lesson in this whole argument for organic advocates. It is important to speak plainly about yield differences and about efficiency. Perhaps Walsh was not sufficiently familiar with hard-headed, well-grounded research on organic practices, but instead may have been reading some excessively optimistic pro-organic public relations. Then, when the PR message was contradicted by the Nature study, Walsh overreacted. It is best all around to state the relative advantages of environmentally sound production practices plainly and precisely from the start.

The USDA says to eat more of this stuff.

In that context, the new “Dietary Guidelines for Americans, 2010,” seems remarkable — even courageous — in its blunt discussion of plant-based diets.

The new edition has a fascinating chapter on eating patterns, focusing on real foods and not just nutrients. This chapter on eating patterns provides a nice counterpoint to the reductionism — what Michael Pollan calls “nutritionism” — of scientific discussion of diet and health. The guidelines’ healthy eating patterns may or may not include meat. For example, the USDA Food Patterns and the DASH diet each include moderate amounts of meat and plenty of low-fat dairy. At the same time, the guidelines explain clearly that meat is not essential, and near-vegetarian and vegetarian diets are adequate and even “have been associated with improved health outcomes.”

In reviewing the scientific evidence on vegetarian diets, the guidelines say:

In prospective studies of adults, compared to non-vegetarian eating patterns, vegetarian-style eating patterns have been associated with improved health outcomes-lower levels of obesity, a reduced risk of cardiovascular disease, and lower total mortality. Several clinical trials have documented that vegetarian eating patterns lower blood pressure. On average, vegetarians consume a lower proportion of calories from fat (particularly saturated fatty acids); fewer overall calories; and more fiber, potassium, and vitamin C than do non-vegetarians. Vegetarians generally have a lower body mass index. These characteristics and other lifestyle factors associated with a vegetarian diet may contribute to the positive health outcomes that have been identified among vegetarians.

The new guidelines have adapted to many of the scientific criticisms of earlier editions. For example, Harvard scientist Walter Willett has long argued that replacing saturated fats with unsaturated fats saves lives, and that refined grains and simple carbohydrates are no healthier than unsaturated fats. The new Dietary Guidelines seem to me to be in complete agreement.

However, not everybody likes the new guidelines. The most vociferous low-carb advocates say it is wrong to criticize consumption of saturated fats. Just this week on the Civil Eats blog (cross-posted on Grist), Kristin Wartman tore into the conventional wisdom on saturated fats: “The notion that saturated fats are detrimental to our health is deeply embedded in our Zeitgeist — but shockingly, the opposite just might be true.” I generally agree with the way low-carb advocates criticize sugar and simple carbohydrates, but this corollary view of saturated fats worries me. Wartman’s view seems threatening to the guidelines’ favorable perspective on near-vegetarian and vegetarian diets, which are typically lower in saturated fats.

Because the saturated-fat corollary to the low-carb criticism of the Dietary Guidelines is widely believed, I need to spend a couple more paragraphs on why a low-saturated-fat diet might be okay for your health.

First, there is the scientific evidence that lowering saturated fat reduces risk of heart disease. If you are primed to disbelieve any reductionist arguments, you can ignore this paragraph. But what strikes me as a lay reader of the scientific literature is how systematic and transparent the Dietary Guidelines’ evidence reviews now are. For saturated fats, you can see exactly what protocol was used to select studies for review, and what criteria were used to evaluate them. You can confirm that the external “Dietary Guidelines Advisory Committee Report” correctly reflected the evidence review, and that the actual Dietary Guidelines correctly reflected the advisory committee report. If you read any of the main low-carb advocates — such as Gary Taubes — see if you can discern in a similar way what his or her implicit protocol was for selecting studies to consider. If you find fault with the Dietary Guidelines’ evidence review, please send a link in the comments to any systematic and transparent evidence review that you find superior.

Second, there are the foods themselves that contain saturated fats. Part of the criticism of “nutritionism” is that USDA lacks the courage to criticize specific foods. The guidelines may criticize saturate fats, but they won’t mention specific foods, the critics say. I have my own slightly gentler expectation for the federal government’s frankness in reporting. If the guidelines use scientific jargon for a food component such as “saturated fats,” I think they should say what foods typically contain that component. This is exactly what the new edition does very well. Here is the new report’s pie chart to accompany the discussion of saturated fat:

Click for a larger version.

So, the main implication of the Dietary Guidelines’ continued criticism of saturated fat is to recommend reducing some combination of: regular cheese, pizza, grain-based desserts, dairy desserts, chicken and mixed dishes, sausage, franks, bacon, ribs, burgers, and so forth. As long as we all agree that occasional treats in reasonable portions are harmless, this advice sounds just fine me. I don’t see why anybody would complain about the Dietary Guidelines on this point.

The New York Times published a front-page exposé by Michael Moss on Nov. 6 about the federal government’s efforts to get us to eat more cheese, even working with Domino’s Pizza to make it happen. (Grist’s Tom Philpott lauded it here.)

Could this be Dairy Management’s next campaign?The government’s semi-public commodity checkoff programs are a big deal, collecting more than $600 million each year to promote a variety of products [PDF]. These programs support many advertising campaigns you may know, for example: “Beef. It’s what’s for dinner,” “Pork. The other white meat,” “Ahh, the power of cheese,” and “Got milk?” The biggest funding shares are for dairy, beef, and pork. There is no checkoff funding for poultry, and very little for fruits and vegetables.

Of course, there has been a backlash to the Times story. In their counterattacks, several recent commentators have come close to denying that these checkoff programs are federal government programs. James McWilliams writes in the Atlantic: “Funding for Dairy Management’s domestic marketing campaign does not come from the USDA, but rather from private producers who tax themselves to pay for the organization’s marketing strategies.” The Daily Yonder wrote that the checkoff programs are industry initiatives and that the Times‘ headline should have been “Industry Group Uses its Own Funds To Promote Its Products.”

These claims by McWilliams, the Daily Yonder, and Grist commenters understate the federal government’s role. Here’s why:

• The federal government established each of the checkoff programs
• The secretary of agriculture appoints the board members from a slate of candidates proposed by the industry
• USDA’s Agricultural Marketing Service must approve every promotion campaign in writing
• The federal government uses its power of taxation to enforce the collection of the funds that sponsor these campaigns. If a producer fails to pay, the U.S. Department of Justice takes them to court. For the cheese and dairy programs in particular, USDA proudly boasts of its central role at great length in its annual reports to Congress.

If these were independent industry entities, then producers would be able to opt out, right? The Daily Yonder claims that producers “tax themselves.” Think about heritage pork producers who are proud of their fat Berkshires and get no benefit from a checkoff advertising slogan that compares pork to chicken. Can they decide freely whether to make a voluntary contribution? No, the assessment is mandatory. Are they being taxed by “the industry”? No, the industry has no such power of taxation. The producers are being taxed by the federal government.

When dissident producers challenged the legality of the checkoff programs, the Supreme Court ruled in 2005 in favor of the checkoff programs, only because the federal government attorney convinced the justices that these programs are from top to bottom federal government programs, and their every message has official status as “government speech.” In his legal analysis of that case, John Crespi explained that the checkoff programs had to pass the following standards to be ruled constitutional [PDF]: “First, the government must exercise sufficient control over the source of the message to be deemed ultimately responsible for the message. Second, the main purpose of the message and the program must be identified as the government’s.”

If the checkoff programs were not government programs, the government would not be allowed to support them using the power of taxation, and the Supreme Court would have ended them.

For this reason, nobody at USDA or the checkoff programs will ever directly deny that they are government programs. Instead, McWilliams and the Daily Yonder have to hint that they think of these programs as private-sector operations, without quoting anybody at USDA or the programs themselves to corroborate this point.

In the backlash against the Times article, misdirection rather than clear statements is the order of the day. For example, the Daily Yonder denies that the programs are using “your tax money.” This is like telling you that the government is not using “your tax money” for the war in Iraq or welfare checks or whatever you object to. The government might be collecting the tax that funds those activities, but it can reassure you that your particular tax payment was not the actual dollars used.

Who cares which tax dollars were used for which purpose? If the federal government collected the tax, and the purpose is bad, we have a right to object.

I say, Congress should either: (a) stop having the federal government enforce the checkoff assessments, or (b) expect that the checkoff messages serve our stated public-health goals at a time when healthcare costs are threatening to bankrupt the government.

The meat and dairy industries can do what they like with their own money. The public power of taxation should be used for the public good. Michael Moss’s article exposed the government’s hypocrisy in trying to serve industry marketing goals and the public good at the same time.