Archive for February, 2011

Making sense of the Polyface calorie numbers

Last summer, I published a post attempting a crude analysis of the inputs and outputs at Polyface Farm. My rough calculations led me to speculate that Polyface Farm may require more calories in grain and soy than it produces in meat, and Joel Salatin seems to have confirmed this when I asked him last month. This analysis has received a bit of attention in various corners of the internet, so I think it’s worth talking about what these numbers might tell us (or not tell us).

On the one hand, I can’t quite endorse the conclusions of Ginny Messina, who wrote in her review of Lierre Keith’s The Vegetarian Myth that the numbers “suggest that there is no such thing as truly sustainable meat production.”

To say that something is sustainable means that it can be continued indefinitely.  Comparing the caloric inputs and outputs of a farm doesn’t really tell us anything about whether that is the case. Moreover, it’s important to recognize that production of plant-based crops requires fossil fuels and fertilizers that are in limited supply, so we don’t have “truly sustainable” vegetable production either.

That’s not to say that the numbers don’t have any relevance to The Vegetarian Myth. Indeed, Lierre Keith cites The Omnivore’s Dilemma extensively, and offers a great example of how one might be misled by Pollan’s work. Keith writes extensively about the environmental damage done by grain agriculture. In her conclusion, she asks,

So here are the questions you should ask, a new form of grace to say over your food. Does this food build or destroy topsoil? Does it use only ambient sun and rainfall, or does it require fossil soil, fossil fuel, fossil water, and drained wetlands, damaged rivers? Could you walk to where it grows, or does it come to you on a path slick with petroleum?

Everything falls into place with those three questions. Those annual monocrops lose on all three counts, unless you live in Nebraska, where it “only” fails the first two.

The reader is to contrast a grain-based diet with one based on pastured animals. Keith writes, “Cattle on pasture in my [New England] climate can easily be sustainable. Joel Salatin is certainly proving that.” We’re to believe that Salatin’s meat passes Keith’s three-question test.

Based on Pollan’s numbers in The Omnivore’s Dilemma, Keith calculates that ten acres of pasture farmed Polyface style can produce enough calories to feed nine people. That might sound impressive at first, but it’s decidedly less so when you consider that this would require grain that could feed even more people. Bringing that feed grain to Polyface Farm depletes more topsoil and requires more fossil fuels than growing and harvesting grain (in smaller amounts) to feed directly to people. More generally, any bad things one might say about grain production will apply even more strongly to the Polyface meal than to a meal of grains with comparable caloric content, and thus support a conclusion opposite the one that Lierre Keith reaches.

However, it oversimplifies things to simply compare calorie content. A meal of corn, soy, and oats would not be nutritionally equivalent to a Polyface meal of similar caloric content. The former meal would, for example, be higher in carbohydrates, lower in protein, and entirely void of vitamin B12. Thus, one might conceivably be able to argue that Polyface-style farming is our best option for producing protein or vitamin B12. (I have no reason to believe that either of these is actually true, and I would be surprised if either were.)

Of course, it makes little sense to consider nutrients individually. A much more meaningful comparison would look at the environmental impact of two nutritionally adequate meals. (There are those who will argue that a meal containing grains can never be nutritionally acceptable, but that is a strictly nutritional question, to be distinguished from the environmental considerations at hand.)

In spite of these limitations, I would emphasize that I don’t think these numbers are entirely worthless. For one, they suggest that a more careful analysis is necessary before Polyface Farm can reasonably be used to support arguments for meat production on environmental grounds. On a broader level, the numbers should be a warning against false solutions. We should be alarmed to see Polyface compared to “the proverbially unattainable free lunch” (as it is in The Omnivore’s Dilemma), and we should ask questions when we see it presented as an alternative to monocultures (as it is in the movie Fresh and Keith’s The Vegetarian Myth).


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The grain inputs on Polyface Farm: Joel Salatin’s take

A few weeks ago, I had the opportunity to attend a panel discussion at UC Berkeley titled “Is Sustainable Agriculture the Future?”, in which Joel Salatin was a participant. For a while, I wasn’t even planning on going. For all my interest in asking Salatin what he thought of my calculations that suggested that his farm was less efficient than feeding grains to people, I didn’t expect a substantive reply.

At the last minute, however, a friend talked me into going, and I was able to ask Salatin a question. I have reason to believe that a video of the event exists, but I have not yet found this video, and as far as I know, it has not been made available. Thus, I’ll summarize the relevant parts of the exchange here, but I’ll update this post with video if it should become available.

The event consisted of a speech by Salatin, followed by some discussion based on a few prompts, followed by audience questions. Salatin’s answer to the first question in this last segment reminded me exactly why I hadn’t planned on going in the first place.

The questioner referred to something from Salatin’s speech, and then asked, “Don’t we need to eat less meat?” Salatin then asked her, “Are you a vegetarian?” as though her dietary choices had some relevance to the question. “Vegan,” she answered. Salatin proceeded to construct a straw man about all life being the same, before assuring the audience that he didn’t mean to be disrespectful and suggesting that the questioner lie down in her garden naked and see what gets eaten. He then went on to argue that animals have important ecological roles on farms, and that meat production can have important benefits like sequestering carbon and building up the soil.

I didn’t find this argument very compelling, particularly as a response to the question that was asked, but it allowed for a convenient segue into my question, which went something like this:

You talked earlier about the role of animals in sequestering carbon and building soil. There’s something else that’s important there, and that is the grain that is fed to the animals. Your farm wouldn’t work without that grain, and it’s not an insignificant amount. Do you get more out of the farm than you put into it? Is Polyface really sustainable agriculture, or is it just outsourcing the environmental degradation to the grain farm?

It certainly wasn’t the best question that one might have asked. In particular, it didn’t clearly articulate the point that much of the carbon and nutrients that farms like Salatin’s added to the soil was brought in through that grain.

Nonetheless, I was pleasantly surprised by the honesty with which Salatin responded. He said that it was a great question, and that I was exactly right. He explained that other people say his farm is sustainable, but he doesn’t advertise it as such. He said that consumer demand for chicken is such that he needs to use a lot of grain right now but added that there is a farmer in Australia (apparently Colin Seis, who has developed a technique called pasture cropping) whose farm does not require the grain input but can only produce poultry once every five years.

It strikes me as not entirely fair to attribute the amount of grain required by Polyface Farm to consumer demand for poultry. That grain isn’t merely poultry feed; it’s also fertilizer for the pasture. When Salatin talks about building up soil, most of the added nutrients are coming from the grain he feeds to his chickens. Seis’s pasture cropping may have the potential to reduce or eliminate that dependence on grain, but I haven’t been able to find much information on the inputs and outputs of that system.

I’ll conclude by cautioning readers not to make too much of Salatin’s acknowledgment that Polyface isn’t sustainable. In the literal sense, the word “sustainable” describes something that can continue indefinitely. I don’t know of any agricultural system (with or without animals) that is sustainable in that sense, though some are obviously a lot worse than others.

Next week, I plan to have another post up focusing on what we can and cannot conclude from my analysis of Polyface. I’ll look at statements made by Michael Pollan as well as discourse that has arisen from The Omnivore’s Dilemma, including comments from pastured meat advocates and vegan advocates.

Correction (2/15): The original version of this post referred to some discussion of nitrogen, rather than nutrients more broadly. On further consideration, I have realized that I misremembered that, and so I have corrected the post accordingly. I believe that the essential point of the post stands in spite of this correction.

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Michael Pollan on Oprah

This afternoon, I found myself having a bit of spare time, and knowing that Michael Pollan would be a guest on Oprah Winfrey’s program about her One-Week Vegan Challenge, I tracked down a television to watch the show. Where I have been able to find video or transcripts, I’ll use direct quotes and provide links, but otherwise I’m going to have to rely on my notes and use paraphrases.

Pollan started off well enough, praising the idea of Oprah’s vegan challenge for raising awareness about our dietary choices. He also said he didn’t think people should eat meat if they’re not willing to look at the way it’s produced. He went on to give vegans credit for animal welfare reforms and praised Meatless Mondays for introducing people to the idea of eating meals without meat.

Alas, it wasn’t long before he gave me something worth writing about. Of his own deliberations on the ethics of eating meat, he said,

I came out thinking I could eat meat in this very limited way, from farmers who I could  feel good about the way the animals lived, and luckily we have a great many farmers like that now, we have a renaissance of small-scale animal farming, and that we’re not feeding them grain and taking that away from people who need that food.

I was almost inclined to let this slide because Pollan is talking mostly about his own personal feelings on the issue. Even though I don’t feel good about the way the animals on small farms are treated, I could agree to disagree with Pollan on that.

However, I do have to wonder if Pollan overstates the number of farmers that produce meat without feeding animals grain. Ruminants like cows and sheep can be fed exclusively grass, but production of pork and poultry tends to include some grain feed, even on small farms. Indeed, my calculations have led me to believe that Polyface Farm (presented in The Omnivore’s Dilemma as a model for good agriculture) is less efficient than simply feeding grain to people. (I’ll have an update related to that calculation in the near future, by the way.)

Pollan went on to explain two of his reasons for not endorsing a vegan diet. His first: “There are great farmers in this country who are doing really good work, and they need to be supported.” By this reasoning, it is irresponsible to advocate against meat consumption because it deprives these farmers of needed income.

I can’t say I find this a compelling reason to eat meat. It rests on an implicit assumption that meat production is something that should happen. Even if we accept the claim that there are meat farmers doing great work, it should be noted that there are also small farms growing plant-based foods, including calorie-dense foods like beans. Shouldn’t these farmers also be supported? Given that most of us have limited appetites and financial resources, we can only support so many farmers. Eating only plant-based foods certainly narrows one’s choice of farmers, but it doesn’t preclude supporting smaller farmers.

Pollan’s second concern regarding vegan diets was about overconsumption of processed foods, though he did acknowledge that one could be vegan without eating processed foods. I think it needs to be pointed out that food processing is a very general term. As Carlos Monteiro wrote (in a column that earned Pollan’s approval),

Much writing that criticises food processing makes little sense. Practically all food and drink is processed in some sense. Various forms of processing are neutral or benign in their effects. Many foodstuffs as found in nature are unpalatable or inedible, and some are toxic, unless prepared or cooked. Further, all perishable foods, unless consumed promptly, need to be preserved in some way.

The issue is not food processing in general. It is the nature, extent, and purpose, of processing. More generally, the issue is the proportion of meals, dishes, foods, drinks, and snacks within food systems, in supermarkets, and therefore in diets, that are ‘ultra-processed’. These characteristically are ready-to-eat or ready-to-heat ‘fast’ or ‘convenience’ products, most notably in the form of fatty or sugary or salty snacks and sugared drinks. These are best all seen as the same sort of  ‘edible food-like substance’ or, as I call them, ‘ultra-processed products’ (UPPs).

“Processing” includes not just hydrogenation of soybean oil and the manufacture of high-fructose corn syrup but also more benign processes, like chopping vegetables (and other things you might do with a device called a “food processor”) and baking a dough to make bread. I suspect that Pollan would agree with me that there’s nothing wrong with chopping a few carrots but that you’d be better off keeping trans fats off of your plate. Most vegan substitutes (like mock meats and vegan cheeses) probably fall somewhere in between these extremes. Though I personally eat these products only very rarely, I have seen no reason to believe that they are particularly unhealthy, and some of them are not even very heavily processed. (I might also add that there’s a certain irony to arguing against vegan diets based on a blanket rejection of “processed” foods when the meat industry’s preferred euphemism for slaughter is “processing.”)

For me, the most noteworthy part of the show came near the end. Unfortunately, I haven’t found any video or transcript from that section, so I have to work entirely from memory. Various Oprah staffers were talking about some of the health benefits they had experienced in their week on a vegan diet. Pollan interrupted, saying that he didn’t want to rain on their parade but that there isn’t anything evil about meat and eating it once in a while is fine. It seemed like sort of an awkward place for such a comment, given that the subject of conversation had been health, rather than ethical considerations.

The conversation shifted to animal concerns, and Kathy Freston explained that she is vegan because she can’t look an animal in the eye and say that it should suffer to satisfy her appetite. Pollan claimed that animals on certain farms live happy lives but have just one bad day (I’m not convinced). He then went on to argue that our system of meat production is brutal but added, “It’s really important to reform that system, not just turn our backs on it.”

Like his earlier argument for supporting small farmers, this is an argument that seems to rest on an unexplained assumption that we need to have some meat production. In the past, Pollan has made environmental arguments for certain kinds of meat farming, but he didn’t do that here.

Anyway, I’d be interested to hear readers’ reactions to the show. Also, I hope you’ll let me know if you think I’ve misremembered something.

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