Waste not, want not.

Since moving to Arizona, I’ve been wondering what to do with my food scraps. As I’ve written about before, food scraps don’t biodegrade in landfills because that process requires airflow. Instead, food scraps petrify. Between 30% and 40% of the food we grow is wasted somewhere between farms and our bellies. And all the food waste that ends up in landfills generates a considerable amount of methane, a powerful greenhouse gas. Food waste is currently a hot topic within the food, energy, and environment sector. In fact, last fall, the USDA and EPA committed to halving the food waste in the US by 2030, and food waste was a talking point during last year’s World Food Day, held by the United Nations.

The first step in curbing food waste in my house is to deal with food scraps. Long ago, we tried worm composting. It is supposed to be easy, but like all things to do with food – deciding what to eat, grocery shopping, cooking, packing healthy snacks – easy can still be time-consuming. We never really got into the groove of working with the worms, and that was before we had two kids to keep track of! In addition, the climate in Arizona is not particularly hospitable to worms. For about six months out of the year, we’re in the triple digits (that’s over 38°C). We’re not keeping a worm bin in the house where it’s air conditioned, but it’s really too hot to keep them outside. And while many cities are starting food scrap recycling programs, we don’t have a program available yet.

As it turns out, some clever people have solved this problem for me. There are now dozens of companies that will pick up food scraps from your home or business and compost them for you. The one in our area is Recycled City. Once a week, a guy named Stan drops off a large plastic bucket (like a painter’s bucket) and a little bag of something called bokashi – it looks a bit like sand and helps break down food waste while eliminating odors. All week long, we throw our food scraps into a bowl on the counter, as needed. At the end of each day, we toss them into the bin in the garage with a little sprinkle of bokashi and snap on the lid so nothing gets out (or in!). At the end of the week, we set our bucket out in our driveway, and Stan replaces it with a clean, fresh one. It’s that simple.

Stan, from Recycled City, takes our food scraps and leaves us a fresh bucket.

Recycled City composts the food scraps it picks up from homes, businesses, and even restaurants. The nutrient-rich soil that results is used for urban gardens in downtown Phoenix, which is classified as a food desert by the USDA. They even offer CSA boxes from their partner farms, and we have the opportunity to get free soil back as part of the service. For the price of a few lattes, we get all of the perks of composting with very little work. Finally, a food system solution that really is both easy and quick!

There is likely some variability among different service providers, but the general idea is pretty universal. You can find a service in your area by doing a web search for “food scrap recycling service” or check out the interactive map by Compost Now.

Moldy veggies, egg shells, coffee grounds, and even bones can all go in the compost bin!

Finding an alternative destination for my food scraps won’t technically help the food waste problem, but it can help keep food out of landfills. And dealing with my food scraps keeps this issue more present in my mind than just dumping stuff in the trash. When I see how much of our produce or leftovers go to waste, I see patterns in what doesn’t get used – like that little bit of extra pasta or the baby onions from the CSA box that I wasn’t sure how to use. All that waste is FOOD, in a world of people who are starving. It’s also money – my money that I consciously devote to getting better food for my family. And it’s all of the water and soil and energy and farm workers and truck drivers and resources both human and mechanical that WE ARE WASTING. Seeing it on a daily basis makes me want to find a solution.

Because food waste is such a hot topic, there are several websites devoted to how you can limit your food waste (like this one and this one). The things that are key for us are making weekly menus and buying only what we need for the week. One issue we’re having right now is that we typically do our meal planning and shopping over the weekend but our CSA box comes mid-week. Some of our CSA produce doesn’t make it to the weekend or we end up doubling up on certain items that we purchased before the box arrived. Rather than letting all that food go to waste, we need to start building some flexibility into our menus – like incorporating a stir fry, curry, or veggie sauté into our menu later in the week. That way, at least some of the produce that arrives in our CSA box can be used right away. Another option is to make salads for lunch, which generally means more nutritious food for less money than going out to eat. Raw, steamed, or roasted veggies (all pretty quick options) make for great salad toppings. There are probably other options, too. Being aware of the problem – how and why food goes to waste in my household – is the first step toward a solution. Next time you clean out the fridge or scrape your plate into the trash, think about how you might solve the food waste problem in your home.

Necessary Steps

Since my last post, I have moved across the country, started a new job, and had a baby. With all of that going on, perhaps it’s no surprise that I have yet to find a new farm from which to buy ethical, sustainably-raised meat. Instead, we’ve been relying on Whole Foods. Through their signs and labels, Whole Foods provides its customers with information about the farming and production practices involved with their meat and, supposedly, has a higher standard than most grocery stores. Up until now, I’ve been mostly taking it on faith, and the word of the employees at the meat counter, that buying meat at Whole Foods is a better choice for the animals, environment, and workers than shopping elsewhere. Now it’s time to dig a little deeper.

Animal welfare is one of my main concerns when it comes to meat. I’d like to think that the animals I eat have only one bad day. That’s far from the case in conventional meat production. Efficiency seems to be the hallmark of the conventional approach. Part of upping efficiency is increasing the number of animals that can be kept in any given operation and strictly controlling the environment in which the animals live.

Because chicken, pigs, and cows do not typically live indoors in highly-concentrated groups, conventional farmers have to take many extra measures to keep the animals alive until they make slaughter weight. For example, when chickens are kept in crowded pens, they peck at each other, which can lead to injury and reduce their value. The solution in conventional farming is to remove the beaks of the chickens. Similarly, when pigs are confined and crowded, they express their natural desire to chew on things by nipping at their neighbors’ tails. To discourage this behavior, farmers routinely cut off the pigs’ tails, leaving only a sensitive nub. That makes it much more painful to be chewed on, causing the pigs to fight back and dissuading the pigs from chewing on each other. The idea that causing animals more pain is a better solution that simply enabling animals to behave naturally highlights the unfortunate priorities of our food system.

Similar to the animals, our environment suffers from conventional farming practices both from the monoculture cropping systems that generate animal feed and the animal operations themselves. When animals are raised in more natural conditions, where they are able to express their natural behaviors, eat the foods they evolved to consume, and contribute to the farm ecosystem, the animals and the environment benefit. A wholly integrated farm is the ideal, but there are many ways in which the lives of farm animals can be improved and are worth supporting.

The Whole Story

Whole Foods uses a tiered rating system for its chicken, pork, and beef. The ratings actually come from the Global Animal Partnership (GAP), which evaluates farms based on long lists of animal-specific metrics. The ratings go from 1 to 5+, and they are color-coded from orange to yellow to green. Higher ratings represent farms that are more animal-centered, meaning that animals are more able to express their natural behaviors. In general, Steps 1 – 3 apply to farms that are more conventional in nature (i.e. animals in enclosed, controlled environments) with many enhancements for the well-being of the animals. Steps 4 – 5+ are for farms that are pasture-centered, meaning that the animals live mostly outdoors in more appropriate environments. All of the chicken, pork, and beef sold at Whole Foods has received at least a Step 1 rating. 

Even farms with the lowest rating, Step 1, have taken significant steps to improve the welfare of their animals over conventional practice. Many common physical modifications, including tail docking (pigs) and debeaking (chickens), are not allowed even in Step 1 farms. By Step 5, no physical alterations are allowed.

Another major consideration when evaluating farms is the concentration of animals. Crowded pens and crammed cages are not allowed. At Step 1, all animals must be able to move about. Chickens must have enough space to flap their wings without touching one another, while pigs and cows must have enough space to exercise, lie down, and move freely. Cows must also spend at least 2/3 of their lives on pasture.

Antibiotics and growth hormones are also disallowed at any step, and animals can never be fed by-products of other animals. Antibiotics, particularly medications that are intended to cure diseases in humans, are frequently used in conventional animal production. In fact, their use is on the rise despite the FDA advising a ramp down. Such pervasive usage is leading to drug-resistant strains of diseases that we used to be able to treat with antibiotics. For more on this important topic, read these recent articles from Mother Jones and Scientific American. Because Whole Foods only carries GAP-rated chicken, pork, or beef, it all comes from animals raised without hormones or antibiotics. 



There are many other factors that go into the ratings evaluation, which can be found on the Global Animal Partnership website as well as in pamphlets available at Whole Foods. Meat that carries a GAP rating is clearly better in terms of animal welfare than that found at most grocery stores. I definitely feel better about buying even a Step 1 product than buying conventional meat, but I would much prefer to buy Step 3 through 5+ meat whenever possible. At the Whole Foods where I shop, there are a lot of beef products with ratings of 4 and 5. Much of it comes from Eel River Ranch in California, a Step 4 organic* farm that raises cows on pasture. There is also Step 3 and 4 chicken from Mary’s Chickens. Unfortunately, from what I’ve seen over the past few months, the selection of pig products is currently limited to Step 1. While we still purchase these products, we now eat a bit more chicken and beef than pork. Some packaged products at Whole Foods are also GAP-rated, including some deli meats from Applegate Farms, evol frozen meals, and Krave jerky. You can see the full list of GAP-rated products on their website.

Although we still plan to join a farm CSA for our meat, if one is available in our new hometown, it is still good to know that we can pick up meat from our local Whole Foods without abandoning our commitment to ethical animal products. Plus, we are using our food dollars to support the GAP ratings program, which promotes better industry practices, and to show Whole Foods that we value ethically-sourced meat and the information that enables us to identify it. All that adds up to a whole lot of piece of mind.

* - A farm’s designation as certified organic is not evaluated as part of the Global Animal Partnership rating system. They are complimentary but quite different sets of metrics.

The Future Frontier of Agricultural Science

Last December, I was honored to attend the Japanese-American Frontiers of Science symposium in Tokyo, Japan. Frontiers of Science symposia (FoS) are organized by the U.S. National Academies of Science, the Kavli Institute, and leading science organizations from around the world – in my case, the Japan Society for the Promotion of Science. The symposia are designed to bring together young researchers from a wide variety of fields, which offers scientists the opportunity to learn the state of the art work being done in other areas and network across the typical boundaries of expertise. In my case, I was the only planetary scientist at a symposium of about 70 participants, and the range of topics included the mathematics and applications of origami, development of a new standard by which we define the kilogram, and the human microbiome. Although jam packed, the sessions were very stimulating and generated great discussions both during and outside of the sessions.

"Any time you do something new in origami, you have to make a bunny."

A little microbiome humor to lighten the mood.

The session I was most looking forward to was Climate Change and Food Security. I hoped the session would focus on agricultural methods that enhance crop resiliency and require fewer resources. The talks began with an overview of the many ways climate change will continue to challenge our abilities to grow food, as well as the growing concern over so-called “hidden hunger”, the widespread lack of nutritious food so severe that it impairs normal growth and function of human beings. An estimated 2 billion people suffer from malnutrition, and poor nutrition is responsible for 45% of deaths of children under 5 [1][2]. The speakers all acknowledged that it is lack of nutrition that will be the next big problem facing humanity. However (and somewhat inexplicably), they then focused on methods of producing “a bigger pile of corn”. That’s right, the session was all about the successes of biotechnology at developing more productive crop varieties.

Quantity vs. Quality

After the talks, the participants asked many critical questions about the biotech approach to food security such as its economic viability in poor countries and issues with soil degradation and water usage. What bothered me the most was that the speakers said nutrition is, and will continue to be, our biggest challenge, but the biotech advances they described do not address nutrition at all. In fact, in the US, most genetically-modified crops (especially corn and soy) are made into food additives and sweeteners, like corn syrup and soy lecithin, rather than actual food. In poorer parts of the world, as one of the speakers pointed out, even industrial-grade corn is used as a food – served as something like porridge. While still largely devoid of nutrition, at least corn does supply edible calories for the very poor.

After the session, I approached two of the speakers* to ask more about the challenges of nourishing the world. The first person I talked to often works in Africa and knew a lot about the particular hardships for poor farmers. She agreed that a good approach to creating nutrition security (rather than caloric security) would be to focus on crops that are inherently nutritious. Whether through changes in agricultural methods, selective breeding, or gene splicing between species, creating more resilient nutritious crops – think lentils and kale rather than corn and soy - must be part of the solution. Unfortunately, the speaker could not think of any researchers currently working on enhancing the yields or the sustainability of nutritious food.

She also pointed out a potential flaw in my analysis of the caloric needs of different countries, which was based on population studies by the United Nations’ Food and Agriculture Organization (FAO). In that study, the caloric needs of a population are determined by age and sex demographics. However, occupation is not taken into account. Farmers, day laborers, or women who trek tens of miles a day for clean drinking water are afforded the same caloric requirement as a typical person, but their actual needs are much higher. Even a person getting 1800 calories a day may be nearly starving because of the exertion required for their daily life. One of the findings of my study was that almost all countries, even those with 30-50% of their populations being classified as food insecure, actually had enough calories to feed everyone. However, based on this new information, it seems likely that income inequality means the poor not only have less access to those calories, they also need more than the FAO has estimated because of the hardships of poverty. In that case, having more available calories could, hypothetically, reduce food insecurity, but only if the impoverished people within the country can actually get more food. And, of course, none of this addresses the availability of nutritious food.

A Culture of Condescension

My discussions with the next speaker were much more troubling. When I broached the subject of growing or breeding more nutritious crop varieties for use in poor countries, he said it wouldn’t be effective because the people in those countries wouldn’t eat the food. They have a culture of non-nutritious foods, he said, using rice as an example. Better to engineer staple crops like corn and rice to have more nutrients and let the poor eat what they like.

I found this attitude, frankly, appalling. The idea that poor people can’t recognize the value of a diverse, nutritious diet is insulting. Assuming that impoverished people in southeast Asia eat a diet of mostly rice because that is their culture neglects the role that poverty has played in restricting diet diversity over time. While the diversity of traditional diets is something I will need to learn more about, it seems unlikely that the nutrient deficiencies currently causing widespread blindness and stunted growth throughout poor populations have been present throughout their histories. In any case, people living in extreme poverty deserve better than to have their nutrition slipped into their rice like parents of a stubborn toddler hiding vegetables in their kid’s pasta sauce.

Another Seat at the Table

The issue of population growth came up many times throughout the session and side conversations throughout the symposium. Because population is increasing, proponents of biotechnology will say that we need to produce more calories even if they are not nutritious. Otherwise, people will starve. There are two problems with this approach. First, as long as the population continues to increase, food production will always have to increase to keep pace. Maybe we can keep squeezing our resources and reducing the nutritional quality of our food to produce more calories, but this seems like a race to the bottom. The other problem is that people need more than calories. It sounds unconscionable to let people starve, but is it any more ethical to give people just enough calories to survive knowing that the lack of vitamin A, for example, will lead to blindness and death? In my opinion, there is no point in creating more calories if we cannot produce nutritious calories because lack of either is too often a death sentence.

In addition to researching nutrition-based approaches to food insecurity, slowing population growth is critical to a sustainable food future. As one speaker pointed out, the advances of biotechnology are not expected to outpace the pressures of population growth on the food supply – not by a long shot. Luckily, the methods for slowing population growth are known. Lift people out of poverty, and they have far fewer children. This is especially true for women because impoverished women have so few opportunities. Becoming a wife and mother is their only value within a society. When women are educated and have access to jobs and careers outside the home, they have a source of economic stability that gives them more freedom to choose when and whether to have children, and they usually choose to have fewer children overall.

Nourishing the world is a harder and more critical long-term problem then feeding the world, but that is the actual problem facing humanity. Producing more calories that are not nutritious or raising crops in ways that degrade or deplete vital resources are false solutions. We need to focus on developing sustainable agricultural practices that produce more nutritious food. We also need to empower the poor, especially women, to both slow population growth and reduce the extra caloric burdens of poverty. This is the true frontier of science, a worldwide humanitarian effort, and a moral imperative.


*Although the names of the speakers are available on the internet, I’m withholding them here because some of what I describe stemmed from side conversations rather than their talks. It’s possible that I misunderstood their comments or that they would have provided more context in a different setting. In any case, I have tried to describe our interactions as best as I can remember them.

[1] http://www.gainhealth.org/knowledge-centre/fast-facts-malnutrition/

[2] http://www.wfp.org/hunger/stats

The Polyculture Project.

Conventional meat production has been (justly) criticized for the strain it puts on the environment and the deplorable conditions in which animals are kept. However, there is an alternative to conventional farming. Diversified, pasture-based farms, also called polycultures, work with the land such that the farm becomes integrated into the natural ecosystem. Multiple species of animals are raised together along with crops that can be used for animal feed and for human consumption. Overall, this type of farming provides many environmental benefits and a higher quality of life for the animals than conventional farms.

A criticism of polyculture farming is that it isn’t productive enough to meet the needs of our population, and thus, meat could only ever be a small part of a sustainable food system. Although often repeated, I have rarely seen this statement quantified, which has led me to ask the following question.

How much polyculture farmland would it take to produce enough meat to feed the US population?

Answering this question requires two types of data: the amount of meat we need for everyone in the US and the amount of meat, per acre, produced on polyculture farms. The USDA and FDA collect and distribute vast amounts of data on the productivity of US farms, but I couldn’t find anything on the productivity of pasture-based, diversified farms. So I set out to collect the data myself.

I first reached out to the farm where I currently get my meat: North Mountain Pastures (NMP), a polyculture farm in Pennsylvania. My family has been part of their Community Supported Agriculture (CSA) program for several years now. Every month, we get a box of meat with a variety of cuts from a variety of animals. The farm is run by Brooks and Anna Miller, who graciously contributed to this project.

Brooks and Anna put together this table of their farm’s output in 2013, which includes all of the animals they raised and the edible pounds of meat typically provided by each animal. The total weight they compute is consistent with a rough estimate based on the amount of meat supplied through their CSA. Brooks and Anna also calculated the acreage of their farm and the land required to produce some additional grains they feed their chickens and pigs. Dividing the total number of pounds (49,855) by the total acreage used (114), gives an annual output of 437.33 pounds of meat per acre.

The other key piece of data is the amount of meat required for the entire US. The USDA recommends that typical adults get about 6 oz of protein each day, which is 0.375 pounds (see MyPlate for more info). For this analysis, let’s assume that all of the protein comes from meat. Throughout a whole year, we would need to produce 42 billion pounds of meat to feed all 308 million Americans their recommended 6 oz. of meat every day. Americans actually consume about 52 billion pounds of meat each year (Earth Policy Institute).

Assuming the productivity of North Mountain Pastures farm, we would need just under 100 million acres of land to produce 42 billion pounds of meat each year and 119 million acres to match current demand for meat.

Those are such big numbers that it’s hard to interpret them without some context. So, let’s compare them to the amount of land we currently use for grazing. According to the USDA (as cited by the EPA), the US devoted about 600 million acres to animal grazing in 2007.

That means we could produce enough meat for the entire US population by converting 16% of our current grazing land to polyculture farming. We would need to convert 20% to match current meat demand.

That doesn’t seem like a lot of land at all. In fact, it seems like diversified farms could actually reduce the amount of land we devote to meat production without reducing the amount of meat people eat. Now, that doesn’t necessarily mean that meat is totally sustainable. There are other environmental impacts we should consider, such as water usage and carbon emission. From the perspective of land use though, diversified, pasture-based farms can provide more than enough meat without requiring any additional land.

If people choose to get less of their protein from meat, it would further lessen the land burden of raising animals. For example, North Mountain Pastures also produces eggs, which we did not include in their meat production numbers. Fish, nuts, seeds, and legumes are also high in protein and can serve as alternatives to meat. However, if sustainability is the goal, we would need to consider the relative environmental impact and scalability of obtaining these other foods to that of meat raised on polyculture farms.

Another benefit of diversified, pasture-based farming is that it hasn’t yet been fully optimized. Farmers and scientists around the world are working on advances that can boost efficiency and lessen the environmental impact of raising animals for food. At North Mountain Pastures, they are working with grain farmers who use no-till agriculture and other ecofriendly methods, exploring ways of reducing off-site feed, and adding an orchard. In a much broader effort, the Savory Institute is devoted to restoring badly managed grazing land and promoting ecologically-sound land management. If we actually wanted to convert current grazing land to polyculture farms, the Savory Institute’s research could help bring the productivity of marginal land closer to a farm like North Mountain Pastures. Additional improvements, as well as more widespread adoption, are also likely to lower the cost of producing meat in this way, a savings that can be passed on to the consumer. Currently, members of the NMP CSA pay about $8 per pound for their meat.

One other potential barrier to producing all our meat on polyculture farms is that we would have to change the way we eat meat. North Mountain Pastures raised 7 different animal species with a wide range in the number of animals of each species. For example, they raised only 12 cows and 10 goats but 240 turkeys and 5200 chickens. To take advantage of a diversified farm requires that we diversify both the types of animals and the cuts of meat we that we regularly eat.

For this analysis, I’ve assumed that any diversified farm could be as productive as North Mountain Pastures. Without any additional data, it’s hard to know if this assumption is reasonable. I will say that I didn’t know how productive NMP would be when I approached them about this project, although that doesn’t necessarily mean that their productivity is typical. And productivity can vary a lot depending on the location of the farm. That’s why I would like to expand upon this study to include as many polyculture farms as I can find. That way, I can better quantify the productivity and scalability of polyculture farms, assess additional environmental concerns, and help develop a pathway to a food system that produces meat without destroying the environment or abusing animals.

It’s a lofty goal and one that I can’t achieve on my own. If you, or someone you know, has data on the productivity of a polyculture farm, please consider sharing it with me. Together, we can turn the polyculture project into a polyculture solution.

Note: This material was originally presented at the 2014 Ancestral Health Symposium. I am so grateful to have had the opportunity to participate in this terrific event and for all of the interest and feedback I received from my fellow attendees.

From farm to table.

It seems that spring has finally arrived in Maryland. We’ve had a whole weekend filled with sunshine and crisp, fresh air. There are daffodils popping up along the creek, little green buds on all of the trees, and a constant buzz of little creatures (human and otherwise) venturing back outside. To celebrate this lovely change of events, we are dusting off the grill and making the one food we have rarely had the chance to eat over the past few years: hamburgers.

It may sound strange – hamburgers are one of the most popular foods in the United States – but eating only ethically-sourced meat means avoiding hamburgers almost everywhere. I recall eating them quite regularly back in college, though, both at restaurants and grilled in my backyard. Hamburgers were the mainstay of nearly all get-togethers: the Superbowl, July 4th, or even just a weekend poker party. I remember those times fondly because, above all, they were celebrations of friendships. They certainly weren’t celebrations of food, however. I bought my burger patties frozen, in a big tan box from Costco. I never thought much about how the meat had come to be in its mechanically-pressed, totally uniform state, and I had no idea how the cows were treated in the process.

Today’s event will be quite different. It will be just me and my little family, celebrating life, hard work, and of course, food.

After the 2013 Ancestral Health Symposium, a fellow attendee who lives nearby contacted me about joining a cowpool. I’d never participated in a cowpool before, but I jumped at the chance. Here’s how it works: A group of people pool money to purchase a half or whole steer from a farmer. Typically, the price per pound is lower than if you bought comparable meat at a store or farmers market, and you can find a farmer who uses practices you are comfortable supporting. Depending on the farmer, you may even be able to visit the farm and your particular cow while it is being raised.

Our cow was grass-fed, raised on pasture at Legacy Manor Farm in northwest Maryland. Although the farm isn’t run with quite the level of management of Polyface Farms (i.e. maximizing integration between the different animals and the land), the animals are raised in a natural, low-stress environment without hormones or antibiotics. Our cowpool, which was broken down into 8 shares, purchased a half-steer. A few months later, our intrepid cowpool leader, Steve, met up with our farmer, Kathy, at the midway point between Silver Spring and the farm to pick up our half steer.

Buying a whole or half animal is quite a different experience than buying cuts of meat at the deli counter. Our meat came, quite literally, as a side of beef, which weighed in at 347 lbs. Although we could have had it broken down before delivery), we instead turned to the experts at The Urban Butcher, an artisan butcher shop located in downtown Silver Spring. These guys were amazing. They allowed Steve to attend and photograph the butchering process. Rather than issuing them a list of cuts, Steve simply let the butchers make the decisions about how best to break down our half steer. Due to their diligence and expertise, only 10 of the 347 lbs were unused, and we got some rather uncommon steaks and roasts in addition to T-bones, ribs, ground beef, and the like.

In early February, all the members of our cowpool met up in order to distribute our shares of meat. It was a lovely day, and our hosts greeted us with wine, a warm fire in their backyard pit, and over 300 lbs of vacuum-sealed and labeled beef. Before we started divvying up the meat, Steve gave a toast. He spoke of the gratitude he felt for this food, which was enhanced by his participation and the awareness it gave him of all the time and effort that goes into raising and butchering a steer. We were able to acknowledge and appreciate the life lost in bringing this food to our table, and the efforts of our farmer and butchers to honor that life.

We then picked numbers out of a hat, and took turns selecting cuts of meat until each share-holder had their allotted amount. My family took home about 40 lbs of grass-fed beef, bones, and tallow. The cuts we selected included: neck roasts, oso bucco, ground beef, kabob, “man” steak, top sirloin roast, short ribs, sirloin tip roast, T-bone steak, picanha steak, clod, and flank steak. We paid $210 for our share, which comes out to about $5 per pound, although excluding the fat and bones brings it up to about $7 per pound.

Over the ensuing months, we’ve been slowly working our way through the meat. Everything we’ve tried has been delicious, in part because we treat each of these meals as a special occasion. Even today, grilling hamburgers on the patio for no one but ourselves, it is a celebration. The ground beef has a heftier consistency, with larger chunks of bright red meat and bright white fat, than you would find in a grocery store. We prepare it simply, alongside grilled portabellas, asparagus, and romaine hearts. We pour some wine. Even our toddler can sense that this is a special meal. It’s not just the amazing taste of the food, it’s also the fact that this meal took effort, that makes it so satisfying. This is a hamburger I will remember.

AHS13: A caveman's guide to world hunger.

In August, I had the privilege of speaking at the third annual Ancestral Health Symposium, which focused on an evolutionary approach to nutrition and health. The title of my talk, “Give them grains? Analyzing approached to world hunger”, was intentionally provocative as this group has pretty negative views of the role of grains in human nutrition. I wanted to get people’s attention because, quite often, the response I get from this community is that they care about making healthy choices for themselves, whether or not those choices are sustainable or widely accessible. While I understand this view, opting out of the conversation about our global food future means that we are less likely to develop a food system that meets the demands of health-conscious people. As it happens, I also care about the accessibility of food, especially for the poor. What follows is the content of my presentation at AHS13.   

According to the UN’s Food & Agriculture Organization, there are more than 850 million starving people in the world. Moreover, there are a staggering 2 billion malnourished people. In fact, malnutrition kills 2.6 million children each year, and 1 in 4 children experience irreversible stunted growth. Vitamin A deficiency alone affects 250 million preschool-aged children; many become blind as a result, and half of the children who become blind die within a year.

Clearly, when we think about how to feed the world, we need to be considering the nutritional value of food as well as its caloric yield. Calories may keep a starving person alive for a day or a week, but to have someone survive for months, years, or decades, nutrition is key.

The most common proposed solution to world hunger is based on the premise that we can use grains to increase the total number of available calories, worldwide. We can do this by growing more grains, increasing grain productivity, and eating more of the grains we currently grow rather than using them for animal feed or fuel. This last point is especially relevant for industrial corn. Several studies have analyzed precisely how many more calories could be consumed if they were eaten “directly” rather than eating animals fed with corn.

To really determine whether eating more corn can help feed the world, we need to consider the type of food produced in this system and the trade-offs between corn and other crops.

In 2011, the US harvested 83 million acres of industrial corn, which does not include sweet corn that you would eat on the cob or out of a can. The same amount of land comprises the entire National Parks system. According to the USDA, 52% of the 2011 corn crop was used for fuel and exports, thereby contributing zero calories to the US food supply. Another 37% of the corn was used as animal feed, leaving only 11% of the crop for food. It seems pretty clear that using more corn for food would produce more calories, but how much more? 

The above chart shows my estimate of the caloric yield of the corn crop based on the current usage distribution. If 37% of the corn crop was eaten indirectly through corn-fed animals and 11% was eaten directly as “food”, I estimate a yield of 1.8 million calories from the 2011 corn harvest. If, however, we had eaten the animal feed ourselves (for a total of 48% in the food category), it could have delivered 2.5 million calories. And, if the entire crop were used for food, it would yield 5.3 million calories. That means we could just about triple the number of corn calories in the food system simply by devoting it all to food. Let’s take this one step further, though. What kind of food do we actually produce from industrial corn?

Before humans can consume industrial corn, it has to be heavily processed. Again, based on USDA statistics, the 2011 corn calories were delivered in the form of high fructose corn syrup, glucose and dextrose, corn starch, alcohol, and corn oil (which makes up the majority of the "Cereals, other" category). Despite the calories, no one can survive on a diet made of these foods. More importantly, consuming calories in these forms does little to reduce the total number of calories a person needs. For example, studies have shown that drinking a soda, which delivers a few hundred calories, will not cause someone to eat fewer calories throughout the day. That means, regardless of how many additional corn syrup calories we can deliver to the food system, we will still need to produce the same number of calories from other foods to meet everyone’s caloric needs. To borrow a term from economics, corn-based calories have diminishing marginal utility.

But let’s forget about calories for a moment. Given that billions of people in the world are malnourished, what are the relative amount of micronutrients that corn would deliver in each of these systems? I chose two micronutrients, vitamin A and folate, for this analysis because deficiencies are known to cause serious, life-threatening health problems.

It turns out that the best source of corn-based micronutrients (based on efficiency and content) actually comes from chicken liver. A back-of-the-envelope calculation reveals that, based on our current corn usage, an acre of industrial corn could provide 141 people with their recommended daily amount of vitamin A and 66 people their RDA of folate through the consumption of corn-fed chicken livers. On the other hand, if we stopped feeding corn to animals, and used it instead to make corn syrup, corn oil, and the like, we would produce zero RDAs of these micronutrients. Finally, if we used all of our corn in such a way as to maximize vitamin A and folate production, we would feed all of our corn to chickens, which would enable us to feed 385 people their RDA of vitamin A and 180 people their RDA of folate with one acre of corn.

Eating our corn directly would provide an increase in available calories, but it would also reduce the already minimal micronutrients delivered by corn. The standard American diet is already rich in the types of food that corn can produce. As a nation, we already generate 3770 calories per person per day, and 70% of the average American’s calories come from refined grain, added sugar, and refined vegetable oil. We also have a nation of very sick people. Over 35% of adults are obese, more than 23 million have Type 2 diabetes, and another 79 million have pre-diabetes. Is this really the diet we want to use to end world hunger?

Given that corn is such an abysmal source of vital micronutrients, it’s worth asking if there is anything better we could grow. Organic produce is more sustainable than conventional agriculture and typically more diverse. The USDA’s organic production survey compiled statistics for the 22 highest yielding fruits and vegetables, which were grow on a tiny 118,000 acres – that’s 0.14% of the land devoted to industrial corn.

Using nutrition data from self.nutritiondata.com, I calculated that the 22 highest yielding organic crops generated 3 million calories per acre. That’s more than corn delivers even if we stopped feeding corn to animals but less than if we devoted the entire crop to food. Nutritionally, however, the organic crops clearly dominate.

To simplify the calculations, I selected two organic crops and used the USDA data to determine the per acre yield of each one. I then calculated the RDAs of both vitamin A and folate. If we grew an acre of organic carrots, we could deliver ¾ of a million people their RDA of vitamin A and more than 1600 people their RDA of folate. From an acre of organic spinach, we would supply almost 61,000 people their RDA of vitamin A and 14,000 people their RDA of folate. 

To summarize, we could produce more calories by eating more corn products, but it would reduce the amount of available micronutrients and not do much to reduce the caloric needs of our population. Sustaining a healthy population is even more problematic as corn provides either micronutrients or calories, but not both. Corn agriculture also requires a great deal of inputs with many negative outputs. In contrast, organic agriculture can provide about 50% of the maximum caloric yield of corn, while also providing prodigious micronutrients. In marginal environments, which are more common in the developing world, organic agriculture can actually produce more calories than conventional, input-intensive agriculture. However, developing truly sustainable agricultural systems, worldwide, will require dedication, creativity, and investments in research and labor.

Overall, growing nutritious crops will likely produce fewer calories. However, globally, we already grow more than 2700 calories per person per day. Even in the countries with the highest rates of hunger, only two actually have too few calories available, and even those are within 100 calories of their daily per capita needs. Chronic hunger and malnutrition are caused by poverty, political instability, and lack of infrastructure. Simply producing more calories, in any form, is unlikely to end world hunger if issues of access are not addressed. Hence, the lower caloric yield of organic crops seems worth the trade-off given their delivery of vital micronutrients, promising yields in places where the poor actually live, and the potential for sustainability.

I think I have made the case that eating more corn products, rather than eating corn-fed animals, is not a good solution to world hunger. In fact, eating corn-fed animal products is the only way to get micronutrients from corn. However, I do not, in any way, support feeding corn to ruminants or raising animals in confinement. Rather, I think we should stop growing industrial corn and go back to raising animals in traditional pasture-based systems. This would likely reduce the amount of meat available in the food system, although I have yet to see a detailed study of the potential yields of polyculture, pasture-based farming systems. Regardless, limiting our consumption of animal products to the level that can be produced sustainably seems like the right approach. 

Overall, this analysis has revealed the importance of considering nutrition, in addition to caloric yield, when making decisions about what we should grow and eat. This above slide lists several ways we can support real solutions to world hunger and organizations who appear, to me, to be taking the right approach. Whether you base your eating habits on what is healthy for you or healthy for the world, I encourage you to get involved and make the food system work for everyone.

I want to thank Eric Huff and Tess McEnulty for their assistance with this project and the Ancestral Health Society for creating a forum for this type of work. Additional citations and background for the calculation of the caloric yield of corn can be found in my previous post. Supporting materials for the hunger assessment by country and specific inputs and outputs of the conventional food system can be found in my 2012 AHS talk, which is described in detail here.

Scientists for sustainability.

As a planetary scientist, I spend most of my time thinking about the moons of Jupiter and the formation of the Solar System. It’s an exciting line of work, but it doesn’t give me much opportunity to help solve the problems currently facing humanity. That’s why I got involved with the Union of Concerned Scientists (UCS), a group of scientists and technical experts who help critically analyze proposed solutions to environmental problems. The UCS produces policy briefs and public outreach materials based on quantitative study in the areas of clean energy, climate change, and food systems (just to name a few).

One criticism of our current food system that I’ve highlighted before is that we devote a huge amount of land and resources to growing industrial grain. Because these grains are not directly edible by humans, the grains we grow are used mainly for ethanol fuel, animal feed, and heavily processed food and additives. While many researchers have investigated how we could use grains differently to produce more calories, I have found very little information on what we could grow instead of grains that might produce either more calories or more nutritious food. Recently, the UCS’ Food and Agriculture group produced a really interesting infographic that begins to address this important question.

Plant the plate.

The USDA and the CDC provide recommendations for the servings of fruits and vegetables that each of us needs to eat in order to stay healthy. Vegetables are particularly important because they provide so many micronutrients. According to the new MyPlate recommendations, fruits and vegetables should make up 50% of our daily food intake. The USDA’s food plan calculator offers more specific recommendations. It says I ought to eat 2.5 cups of vegetables a day, varying the kinds of vegetables I eat throughout the week, and 1.5 cups of fruit each day. My husband should get 3 cups of veggies and 2 cups of fruit per day. We actually aim for about 8 cups of veggies a day because that’s the best way to meet the recommended allotments of micronutrients, but 2.5 cups is a good minimum.

Interestingly, the Union of Concerned Scientists determined that we do not actually grow enough fruits and vegetables for every American to consume the recommended daily intakes. Currently, only 2% of the farm acreage in the US is used to grow produce. We would need to more than double that number in order to provide enough food for everyone to eat a healthy amount of produce. Even with these adjustments, the total acreage devoted to fruits and vegetables would only be 5.28% of our total farm acreage.

It’s unclear why we grow so little food that we know is essential for good health. Certainly, the government subsidies for grains play a role – driving down the price of grain, which then becomes an extremely profitable raw material for food companies. Demand also plays an important role, though. Have we become so accustomed to processed food and sugary beverages that we no longer demand produce, or is the price difference between fresh and processed foods turning people away?

Counting calories.

Pro-grain groups often cite world hunger as a justification for using any means necessary to produce more calories. However, in the United States, we have over 3700 available calories per person per day [1] – far more than any of us needs to consume. However, if we followed the UCS’ suggestion and switched 23 million acres of grain-producing cropland to the growing of fruits and vegetables, we probably would reduce the total number of calories we produce.

Grains go through so many changes before they are consumed that it’s hard to say how many calories would be produced on 23 million acres. Here’s my first attempt to estimate how much of an impact such a change would have on the caloric yield of our food. For simplicity, I’ll just focus on corn for this analysis.

According to the USDA’s crop statistics, the 2011 corn harvest was used for a variety of purposes: 40% went to ethanol fuel, 12% was exported, and 9% went to food sweeteners and additives, including high fructose corn syrup (HFCS), glucose, dextrose, food starch, and alcohol. Only 2% of the corn harvest was used to make corn-based foods (e.g. corn chips), while 37% went to animal feed, an indirect source of edible calories. That means 52% of the corn harvest did not contribute to the available calories in the US, and another 37% entered indirectly through consumption of meat, poultry, dairy, and eggs from corn-fed animals.

The whole point of switching from grains to fruits and vegetables is to enable people to eat the daily recommended values of these foods. So, presumably, 100% of the harvest from the additional 23 million acres would be consumed by humans. Because 52% of the corn crop does not contribute to edible calories, the new fruits and veggies could provide only 48% of the calories from the corn they replaced without changing the number of edible calories in the food system.

Of the corn that directly delivers calories, the largest portion becomes HFCS, which contains about 80 calories per ounce*. About 32 pounds – or 512 ounces - of HFCS can be produced per bushel of corn [2]. In 2011, about 25 bushels per acre were used for HFCS, yielding about a million calories over the year. The next largest portion went to glucose and dextrose. If these sugars have similar conversion rates (a big assumption), then the 6% of the corn crop used to make HFCS, glucose, and dextrose produced about 1.7 million calories. I was unable to find enough information to deduce the caloric yields per acre of food starch or alcohol, but these are likely negligible.

Edit (09/05/13): In the above analysis, I incorrectly calculated the number of bushels per acre that were devoted to each type of food product. The numbers should be about 6 bushels per acre for HFCS, 3 for glucose and dextrose, 3 for starch, and 1.5 for alcohol. I have also found the information for the corn starch conversion; one bushel of corn can be used to make 32 pounds of corn starch, which contains 107 calories per ounce. Hence, the total caloric yield of these "food uses" was only 531,000. I am still neglecting calories from corn-based alcohol in this analysis.

Jonathon Foley, of the Institute on the Environment at the University of Minnesota, stated that the caloric efficiency of converting corn to edible animal products ranges from 3% to 40%, depending on the product (e.g. steak vs. eggs). So the 37% of corn that is used for animal feed contributes far fewer calories than were initially grown. How many calories would the corn deliver if it wasn’t used for animal feed? Well, if it’s made into HFCS, as most of the corn is, the 50.5 bushels per acre devoted to feeding animals would produce approximately 62,000 to 825,000 calories depending on which conversion rate is assumed.

The 2% of the corn crop that is used for food goes into a wide variety of products, from corn chips to polenta. That makes it virtually impossible to determine the precise caloric yield per acre. However, according to the Corn Refiners Association, corn oil is the major food item produced with corn. One bushel of corn produces 0.7 pounds of corn oil [3], which contains about 240 calories per ounce. Making the simplifying assumption that all 11 bushels per acre that were used for food were delivered in the form of corn oil yields just under 30,000 calories.

Edit (09/05/13): As above, the bushels per acre is an over-estimate. The correct number is about 2,  which yields about 13,500 calories.

Based on these assumptions, I estimate that the 2011 corn crop supplied between 1.792 and 2.555 million edible calories per acre to the US food system, depending on the relative amounts of different animal products produced.

Edit (09/05/13): My revised estimate is 600,000 to 1.8 million calories. In the Foley article, he states that the US corn supply delivers about 3 million calories per acre per year, but there is no reference or data provided. I can only guess that my calculation includes some oversimplifications that account for the discrepancy. However, he also states that the corn crop is used to make polenta, which is actually made from sweet corn. The crop data from the USDA, upon which I have based my analysis, does not include sweet corn. So, perhaps we are using different data as well as different assumptions.

Also in 2011, the USDA reports that 1.76 million acres were devoted to the growing of vegetables and melons, which resulted in 43.2 billion pounds of food [4]. That’s ~24,500 pounds per acre. The top three crops were onions, head lettuce, and watermelon. Onions have about 12 calories per ounce, lettuce has 4, and watermelon has 9. Using the average of these three as representative of the caloric yield per pound of vegetables results in 3.14 million edible calories per acre.

It’s pretty surprising to think that vegetables and melons produce more calories per acre than corn. The reason is the way we use corn. If we instead used the 40% of the corn crop currently devoted to ethanol production to make corn oil or high fructose corn syrup, the corn crop would deliver significantly more calories than the vegetable crop. Of course, having more corn oil or corn sweetener may not have a significant benefit to human health.

We could also produce more edible calories if we did not use corn as animal feed. However, as long as we are growing corn, perhaps using it to create foods like eggs and pork is a nutritionally superior choice. Feeding corn to animals, especially cows, has many other drawbacks, though. Overall, the lack of an efficient pathway from the corn crop to nutritious food reinforces the idea that we ought to grow less corn, and use the land to cultivate nutritious foods instead.

The recommendation from the Union of Concerned Scientists is to convert 23 million acres of land from grain to fruits and vegetables in order to provide all Americans with their daily recommended intake of these foods. My analysis, which necessarily required a lot of simplifying assumptions, shows that this switch would actually deliver more edible calories to the food system, in addition to more micronutrients. It also shows how inefficient the corn-based system is at producing actual food. This makes me wonder just how much we could change the food system without a significant drop in calories. Could we switch to all organic production? Diversified farms? Farms that combine plants and animals? Given that we currently produce a surplus of calories, can more extreme changes in production practices (e.g. devoting more land to pasture for animals) still provide enough calories to feed our population? And would those calories provide superior nutrition to what we currently produce? Hopefully, with more research into sustainable farming practices, we can begin to answer these questions and design a food system that can sustainably produce nutritious, delicious food.

I think our food system should produce more fruits and vegetables instead of crops that are not used primarily for food. The Union of Concerned Scientists is doing a great job of showing how to make these changes and informing food policy decisions. You can learn more about their vision for the future of the food system in their recent policy brief, The Healthy Farm. You can also follow their blog, The Equation. If you like what you see, consider joining and taking action. Together, we can “plant the plate” and get on a better path to a sustainable food future.

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Caveat to my analysis: More of the wheat crop is devoted to food products than the corn crop. Hence, switching from wheat to fruits and vegetables could result in a net drop in edible calories in the food system. Most farms cycle between wheat, corn, and soy, so it’s not quite as simple as switching out inefficient corn for produce. Although, perhaps fruits and vegetables could be added to the rotation instead of corn. This type of analysis is necessarily complicated, especially by the diversity of end products from corn, wheat, and soy. If you have ideas as to how it could be improved, or if you know of similar analyses elsewhere, please leave a comment!

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References:
[1] Data from FAO statistics website
[2] Fooducate article (32 pounds) and 2008 Iowa State Extension Service publication (33 pounds)
[3] North Dakota State University Extension Service website
[4] Data from USDA Economic Research Service website

* All calories determined from Calorie King