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RHR: The Science of Soil, with David Montgomery and Anne Biklé


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Authors David Montgomery and Anne Biklé join Chris on this episode of Revolution Health Radio to discuss soil health and nutrition. They discuss the importance of the microbiome of the soil, how conventional agriculture adversely affects the soil microbiome, how disruption of the soil microbiome has led to a decline in the availability of nutrients in the food that we eat, whether regenerative farming is scalable and how it can improve soil health, some things that we as individuals can do to make better choices around food, and why improving and maintaining soil quality is one of the fundamental things we need to do to preserve our health and well-being.

In this episode, we discuss:

  • Why soil health matters, and the history of where we are now. We get enough food, but do we get enough of the nutrients that actually support our health?
  • How conventional agriculture causes a dilution effect and undermines the biological mechanisms that provision nutrients into the food we eat
  • The key factors that contribute to the health of the soil microbiome and contribute to the amount of living organisms in the soil
  • The common argument that regenerative farming is not scalable
  • How good soil health leads to synergistic, nutrient-dense food sources
  • What regenerative farming is and how its processes can help build soil organic matter and support optimal nutrient cycling
  • The urgency of switching globally from conventional to regenerative agriculture and the growing popularity of sustainable farming among the younger generations
  • What we as individuals can do to support biotic diversity and increase the nutrient density of the food that we’re eating

Show notes:

Hey, everybody, Chris Kresser here. Welcome to another episode of Revolution Health Radio. We’ve talked a lot on the show about the quality of the food we eat. We’ve also discussed in a few different episodes how important the way we grow food is. I’ve had Will Harris from White Oak Pastures and Joel Salatin as guests on my show in the past to talk about regenerative farming and what that approach to agriculture can add, in terms of biodiversity and nutrient density of the plants and animals that we eat.

Today, I’m really excited to welcome David Montgomery and Anne Biklé as my guests. David is a MacArthur Fellow and professor of geomorphology at the University of Washington, and he’s internationally recognized as a geologist who studies the effects of geological processes on ecological systems and human societies. Anne is a science writer and speaker focused on the connections between people, plants, food, health, and the environment. We’re going to be talking about their newest book. They’ve written several books, all of which are excellent, starting with Dirt back in 2007, when hardly anyone was discussing the importance of soil quality. They pioneered that conversation early on. Their recent book is What Your Food Ate. This book looks at the topics of soil health and nutrition, organic matter and living organisms being key factors in soil health, the importance of the microbiome of the soil, and there are a lot of fascinating parallels between that and the importance of the gut microbiome for human health, how conventional agriculture adversely affects the soil microbiome, how disruption of the soil microbiome has led to a decline in the availability of nutrients in the food that we eat, how microorganisms in the soil contribute directly and indirectly to the health of the soil and to our health, and how regenerative farming can stop soil erosion, improve soil health, and build up soil carbon.

We also discussed one of the more common objections to regenerative farming, which is that it’s not scalable, and we have to choose between quantity and quality. Toward the end of the show, we talk about some things that we as individuals can do to make better choices around food and support improving and maintaining soil quality, which is one of the fundamental things we need to do to preserve humanity and our health and well-being. I really enjoyed this episode [and] the fascinating conversation, and I hope you do, as well. Let’s dive in.

Chris Kresser:  David and Anne, welcome to the show. It’s such a pleasure to have you on.

David Montgomery:  Thank you. It’s a pleasure to be here with you.

Anne Biklé:  Yeah. Thanks a lot.

Chris Kresser: I’m going to start with a very simple question, which is, why should we care about soil health?

David Montgomery:  Well, there [are] two ways to look at that. One is at a broad societal scale, and the other is at an individual scale—the health of each of us. Soil health turns out to really matter, I think, for both. At the broad societal scale, healthy, fertile soil is what has fed us through the agricultural era in the post-glacial world. You can chart the course and fate of civilizations based, in a way, on how they treated their land. It sets the stage upon which human history is played out. We wrote about that in Dirt: The Erosion of Civilizations a few years back. If you look at our individual health, trying to connect the dots between soil health, the health of crops, the health of livestock, and the health of people is what Anne and I wrote about in our new book, What Your Food Ate. There’s a lot of detail on how you can connect those dots. The more that we’ve learned in the last 80 years [of] the modern agricultural era, the more it seems those dots connect, and the better the science supports there being connections as complex and nuanced as they are.

Chris Kresser:  This is definitely not my area of expertise, and that’s why I’m looking forward to talking to you about it. I’m more involved in what happens after people take food out of the soil. But it seems to me that earlier in the 20th century, the main focus, from an agricultural perspective, was, “How are we going to feed the growing population?” A lot of the efforts were geared toward goosing the system to yield as many crops as we possibly could. There wasn’t a lot of attention, or even questions being asked, about how those inputs were going to affect the health of the soil over the long term. Is that a fair characterization, number one? And number two, how has that changed? At least in your experience, over your lifetimes. I know you’ve both had long careers in these fields. What changes are you seeing now?

“Well-Fed But Undernourished”

Anne Biklé:  That’s a really good question, Chris. It always reminds me that famine has a long, long shadow when it comes to humanity. And that, of course, was part of the motivating reason and why enough food yield, that’s what yield is, when people talk about that, do we have enough to at least get calories into everybody? It’s not just a long arm; it’s a strong arm, too. At least for those of us in the Western world, the problem of enough calories was solved a while ago, and yet we have not been able to pivot to dealing with another aspect of our health, which is, are we getting enough of the nutrients that actually support our health? These are things that don’t really have caloric value. Mineral elements, phytochemicals, those kinds of things.

So it is a fair characterization to say that we’ve had a really tough time in agriculture. We can’t let go of yield because we still need to grow and harvest enough food to feed people, but we need to bring another factor into that, [which] is, what is the quality of the food? Is it suffused with nutrients? And when I say nutrients, that’s a really broad category, in my mind, as a biologist. It’s way more than just calories. We need to bring that aspect into things so that we’re growing enough food that has the things in it that are vital and critical to human health, especially once you get past the stage of infancy and young adulthood. And that becomes a question of, okay, we’ve built this body, [and] the biomass is pretty set, we hope. It’s not continually growing and getting bigger, anyway. So if we have this biomass, what do we need to do to take care of it [and] keep it functioning and in good health for as long of a person’s life as possible? Because I don’t think anybody is looking forward to living the last 25 or 30 years of their life with chronic illnesses that are debilitating. It wrecks your quality of life.

David and I see [that] some types of farmers are realizing this, and they’re beginning to change their practices so that it’s changing what gets into the crops and the animals that become a part of the human diet.

Chris Kresser:  It’s such an important point. The timing of this podcast recording is perfect because in the last two years, after I’ve been working as a Functional Medicine clinician for 15 years, I’ve come to believe that nutrient deficiency or nutrient inadequacy is [the] tip of this hidden iceberg that is dramatically impacting our health and our quality of life. And yet, there’s hardly anybody talking about it, even in the Functional Medicine world.

I think part of it comes down to the difference between deficiency and inadequacy. We’ve had this view [in the past that] we need a certain amount of a nutrient to avoid scurvy, or rickets, or beriberi, or pellagra. We’re past that now. We have higher aspirations than just [not] dying from a frank nutrient deficiency. We want to live a long, healthy life, avoid chronic disease, all the things you talked about. And we know now from extensive research that the level of nutrient required for that is much higher than the level that’s required to avoid an acute deficiency-related disease.

So I’m happy to be having this conversation because you could look at it and say [that] we are now extremely well-fed, but we’re undernourished. I saw a statistic the other day I think you’ll appreciate, that average calorie intake has increased by 24 percent since 1961. And I think that study was in the early 2000s, so we’re now 20 years past that, [and] I’m guessing that it’s actually increased more. But I know, from reading your book and other resources, that the nutrient levels in our food have steadily declined over that time. So you have a double whammy, where the calorie intake is going up from ultra-processed and refined foods that are devoid of nutrients, and the nutrient levels of the good, healthy foods that we might eat are going down. Let’s talk a little bit about that. Why is this happening? How does this relate to the microbiome of the soil, which I know you focus a lot on? What’s going on in the last 50 years that’s causing this decline in nutrient value?

The Impact of Conventional Agriculture

David Montgomery:  There’s a couple of angles there. In effect, what we’ve done in modernizing our agricultural practices is that we’ve looked at prioritizing the aspects of agriculture that will help us survive, but we’ve left those aspects that could help us thrive off the table inadvertently as we have sought to feed the world. How does this all connect? When you look at things like the mineral micronutrient acquisition by crops, there [have] been studies that have documented declines in the mineral content of foods over the last 80 years. Some of them are controversial, [and] some of them have gone back and forth. But when you review them all, like we did in the book, it’s pretty clear that there have been declines, and there’s a widely accepted hypothesis in agriculture about why that is. It’s only part of the story, in our opinion, but part of the story is fairly well accepted, and that’s what’s known as the dilution effect.

Imagine you’re growing a wheat plant, and you breed it to have twice as many seeds as it had before. That sounds good. It’s twice as many calories [and] it’s twice as much food. But if that plant takes the same amount of zinc out of the soil to park in those seeds, it’s spreading it to twice as many seeds, so each seed gets half the zinc. There’s a fairly simple effect that’s been manifested through crop breeding where we’ve bred for yield without paying attention to simultaneously breeding for greater nutrient uptake to support a higher nutrient density in that yield. So that’s part of the problem. The one part of the problem that has been shown to not be a contributor to the nutrient decline is the depletion of minerals in the soil. That’s kind of a red herring. And there are good studies that have looked at that. There’s [another] aspect though, and that’s interrupting the soil life that helps crops get those mineral elements out of the soil. Zinc trapped in a soil particle doesn’t do a crop or a human any good. You need to get it into the crop and then into the person to actually help our micronutrients supply. It turns out the biology, soil life, is the agent that helps get those micronutrients out of soil particles and into crops. Two of our primary agricultural methods at this point, intensive tillage and the liberal application of synthetic nitrogen fertilizers, both undermine the fungal life that helps prospect and get those micronutrients into our crops.

If we use a lot of tillage and a lot of nitrogen, we can grow high yields. But those methods undermine the mechanisms, biologically, that help provision those crops with high abundances of mineral micronutrients. That hasn’t received a lot of study. We review the background on that in the book and make the case for why that’s an important factor to think about. What we’re trying to do with What Your Food Ate is to let people know that when you think about healthy eating, of course, we should think about what we eat. That’s a huge factor. But the additional element is how [it] was raised because that can affect the provisioning of things that we actually want in our food.

Chris Kresser:  That makes a lot of sense to me, as a clinician who’s focused on gut health and reviewed many studies on the relationship between the gut microbiota and our absorption and assimilation of nutrients. There [are] so many complex interactions that happen between the bacteria and yeast in the gut. Not only compounds that they produce on their own that are useful to us, and I’ll come back to that because I know you’ve written about that, as well, but their ability to extract nutrients from food. We know that someone who has an unhealthy gut microbiota can eat the exact same meal as someone who has a healthy gut microbiome, but they’re going to get totally different nutrition out of the meal as a result of that. It sounds like that’s also a factor in the soil.

Anne Biklé:  Oh, yeah, definitely. I really like framing things in terms of diet because the soil can have a diet, the soil microbiome has a diet, just like a person and our microbial communities. The whole game [when it comes to diet] is that these microbes, whether it’s bacteria, fungi, or protists, play a huge role in acquisition and in processing. Sometimes that word “processing” gets bound up with ultra-processed foods, and I just want to state here for the record [that] processing is not a bad thing. When you go and get tomatoes and make tomato sauce, that’s a form of processing. We’re not talking about wholesale alteration of things, plus the introduction of other things. What’s happening in the soil and in the gut is that these microbes are acquiring and helping to process, in many cases, various components in the diet of a plant, as well as the diet of a person. We’re not only what we eat; I think we’re more than what we eat, when, to your point, the microbial communities in the gut and the soil are functioning like they’re supposed to be. And I always like to say, normal function is good enough. We don’t need super anything. We just need normal. When you get to normal, then you get to functional.

Chris Kresser:  Let’s talk a little bit about that. You mentioned, David, some of the threats to the soil microbiome, like fertilizers, herbicides, pesticides, tillage, and bare fallows. I know those all threaten soil health, just like antibiotics and chronic stress and [non-steroidal anti-inflammatory drugs] threaten our gut microbiome from processed food. What’s the fiber of soil? What are the two key factors that contribute to the health of soil and the health of the soil microbiome?

Importance of the Microbiome of the Soil

David Montgomery:  There [are] two big aspects of that. I would argue that soil organic matter would be the fiber equivalent for the soil. The parallels between what goes on in the human gut and its relationships with our microbiome and what goes on in the soil are pretty striking and profound. You can go down the list, from nutrient acquisition to teeing up a defensive system, [to] communication. All the functions of chemical communication between microbes and the host organism, whether a plant or a person, are pretty profound and integrated evolutionarily into maintaining the health of that organism on both ends of it. They’re mutually beneficial symbiotic relationships. The microbes end up making things that benefit the health of the host organism and what does the host organism do for the microbes? It helps feed them.

So in terms of soil health, the provisioning of soil organic matter in the soil is a big one. Also, the provisioning of exudates from the plants. What are exudates? Well, they’re things that plants exude or drip out of their roots. When you look into what kind of compounds plants are making through photosynthesis and then exuding out through the roots, they’re things like carbohydrates, proteins, lipids, [and] fats. It sounds like food because it is food. It’s food for microbes. They’re basically laying out an underground smorgasbord for organisms that will then congregate around their roots and metabolize those exudates into things that help benefit the plants. When you think of what makes for a healthy, fertile soil, it’s a good amount of organic matter for the climate in the region and the soil, which are all factors in what’s good. But also, a healthy component of soil life that is in a commensal, or beneficial, relationship with the vegetation growing there. Those are the things that too frequent tillage or too intensive use of synthetic fertilizers can disrupt because they encourage the degradation of that soil organic matter and they change the community of life in the soil. It’s not just enough to have life in the soil. You want life that is actually acting in concert with the crops you’re trying to grow and provisioning the nutrients that you want to nourish the people who eat those crops. Scrambling who’s in that community can have a big effect on not just productivity, but also the health of crops.

Chris Kresser:  Aside from the methods of agriculture and the chemicals that are being used, what are the other factors that contribute to organic matter and the amount of living organisms in the soil? There’s been, for example, a movement in the last several years [by] advocates of plant-based diets arguing that we should remove all animals from the food ecosystem, essentially. What do you think about that argument? What are the potential problems with that approach?

David Montgomery:  Well, the potential problem with that is, if we entirely switch to a plant-based diet but we farm those plants in ways that degrade and destroy the soil, we’re no better off. That’s been the story of many societies in the past, in terms of how farming practices, whether or not they integrated animal husbandry into them, had degraded land enough to impact whole societies. Whatever one chooses to eat, in terms of evaluating both the health impacts and the environmental impacts of it, the first question someone ought to be asking is not necessarily what you’re eating, but how what you’re eating [is] grown. Because there [are] ways to raise livestock that can actually enhance the fertility of the land, and there’s a long history of livestock manure in the land when you relate it to the soil microbiome. You can think of a cow, for example, as a wandering inoculation machine. Their manure is full of microbes, and if they’re the right microbes that help support healthy soil, that can help build the fertility of the land. In what we’ve looked into, in terms of the effects of livestock grazing on the environment, it really depends on how the cows are managed. It can go either way. I’ve seen plenty of examples where overgrazing led to gullying and destruction of land, and frankly, I was quite surprised in visiting some regenerative ranchers over the last five or six years to find that they had used livestock as a tool for rebuilding soil health. There [are] connections to human health that get into based on what those livestock are eating, as well.

I think that the arguments we ought to be having over plant-based versus animal-based diets should be a lot more nuanced and ask the question of how are those plants raised and how are the livestock raised? There’s no question that a meat-rich diet [of] livestock raised in confined feeding operations and fed mostly feeds derived from crops that were grown in ways that degraded the soil [is] not good for people, it’s not good for cows, it’s not good for the land, [and] it’s not good for the planet. But that doesn’t necessarily mean that there’s no room for animal products in agriculture and in healthy diets and in healthy landscapes.

Chris Kresser:  I had Will Harris from White Oak Pastures on my show. You might be familiar with him. [I also had] Joel Salatin [on] in the past, and those were very interesting conversations about the different ways that animal husbandry and raising animals and incorporating them in the food system can happen. They’re a polar opposite of how things tend to happen in industrial agriculture. One of the biggest questions that comes up, and I know you’ve addressed this, is, “Is that kind of agriculture or method of raising food scalable?” People say, well, that’s nice in a boutique way. It’s nice for White Oak Pastures; it’s nice for Joel Salatin. But, come on, let’s get realistic. We need to feed the world, and the only way we’re going to do that is with monocropping soy and corn and rice and wheat. What would you say to someone who has that objection?

Is Regenerative Farming Scalable?

Anne Biklé:  I think that the question of scale on anything is important.  I also think at the same time, we probably all realize at this point, especially somewhere like the United States, or some of us at least may realize this, we don’t need to be consuming the amount of animal protein that we do. Especially if you’re eating it at nearly every meal. And we certainly ought to be thinking about consuming more nutrient-dense animal protein. At the same time that I say nutrient-dense, I also mean animal protein that [does not have] antibiotics, low levels of phytochemicals, [or an] unhealthy balance of fats. That’s how I respond to the scale thing, is [that] I don’t really think we need to scale this up. Animals have always been a part of agriculture. You look around at other cultures that have animals in their farming systems and they tend to be breeds that do very well for a local climate and a local region. I remember reading about cows in, of all places, Kerala, India. This is a southern part of India that is incredibly hot, and these cows are about the size of ponies. It’s not this giant Holstein that has been bred so large [that] it can’t survive in a pasture environment. And that goes sort of back to your initial question about yield. We’ve gotten so mixed up when it comes to animals and yield in some ways that we have forgotten that there are these breeds of animals, whether you’re talking [about] a ruminant, or pigs, or chickens, that have always done well in particular conditions. And that the farmers who live in those regions know what those breeds are. So I don’t think it’s so much about [scalability] as it is about adaptability and [resilience]. We should be using animal breeds, especially given our changing climate, that work well in the regions where people live. And at the same time, eating higher-quality animal proteins.

David Montgomery:  I actually think that the feed the world and yield question is a bit of a red herring. The reason I would argue that is, of the regenerative farms that we visited, and particularly the ones I wrote about in Growing a Revolution, [the] yields of these regenerative farmers were comparable to their conventional neighbors, if not higher. They were able to grow as much, if not more, food with healthy, fertile soil, and they did it with less fertilizer, less pesticide, and less diesel. Better for the environment. They grew just as much food.

Now, in terms of the size of farms, that’s a really interesting question. The largest regenerative farms I’ve been on are [around] 20,000 acres. They’re huge. In the Dakotas. You could see it over the horizon. They were growing mostly grains and commodity crops, but they were doing it in a different way than we’d have to intend to do it conventionally. And their yields are comparable to what their conventional neighbors are getting. Their profits were better because they spent less to grow the same amount. You also can look at the yield question through a couple [of] other lenses. In terms of scalability, there [are] two models for thinking about that. There’s the large farm versus small farm question. I think you can do regenerative on both. There’s also the question of, what’s your strategy for scaling? Because you could scale out production by cloning lots of small farms rather than just consolidating them into a few big farms. Our agricultural policies, incentives, and subsidies for the last 80 years in this country have favored large farms. That’s a policy choice. We could reverse that. We could start favoring and subsidizing and helping out farmers to do small farms. Why might that make sense for feeding the world? Well, because if you look at the data in terms of how much food you can produce per hectare of land, small farms produce more than big farms. Now, if you look at it for one crop, say you just look at corn, it flips. It’s the reverse. A monoculture is really good for growing a whole lot of one or two things. If you want to grow a lot of food, on the other hand, you grow diverse polycultures on small farms, and you produce more per hectare. And if you look at who feeds the world today, something like 70 percent of the world’s food comes from small farms. Most of that’s in the non-westernized world. We’d have to think in terms of a regenerative agriculture strategy, [and] how [it’s] different in different portions of the world, with access to different technologies and capital and so forth. But the basic idea that you can farm in ways that build soil health, what we call regenerative farming, is something that can work for the scalability; it can work for the yield question. It’s a very different way of thinking about the soil and requires very different ways of farming. But we’ve seen it work.

The roots of good health start on farms. In this episode of Revolution Health Radio, David Montgomery and Anne Biklé show us why what’s good for the land is good for us, too. #chriskresser #soilhealth #plants

Relationship Between Soil Health and Nutrient Density

Chris Kresser:  There [are] so many ways I want to follow up with this. I wanted to circle back to what we started talking about, which was yield. Are you aware of a metric that is used that combines calories with nutrient density for yield in agriculture? Is there such a thing?

David Montgomery:  Well, in effect, nutrient density is nutrients per calorie, is one way to think about it. So in a way that kind of incorporates it, but not, I think, directly in the way that you’re seeking.

Chris Kresser:  I guess what I’m wondering is, is that even part of the conversation around yield in most conversations? Because if we think about corn, okay, great, we can grow a ton of corn, we can grow a ton of rice, we can grow a ton of wheat, and that’s going to produce a certain amount of calories. But as we’ve discussed, if our goal is to promote optimal health, we’re not just thinking about calories; we’re thinking about nutrient density. There was a study published by Ty Beal and Flaminia Ortenzi in March of this year, and it was the first study that ever quantified nutrient density of common foods that took bioavailability into account. We know, of course, that [of] the amount of nutrients listed on a food label for a particular food, we don’t ever absorb a hundred percent of that because of compounds like oxalates and phytic acid that interfere with our absorption of minerals. I know there are parallels in the soil, as well.

Four of the top seven foods from a nutrient density perspective were organ meats. These, of course, have fallen out of favor in the modern diet. But it strikes me that, if a small farm has animals and is producing animal foods, it’s producing dark leafy greens, which are very high on the nutrient density list. It’s producing eggs, which are also very high. Even if the total caloric yield of that farm is way lower than the neighboring monocrop of corn producer, we’re going to want more of those small farms any day of the week because from a health impact perspective, that’s going to be far better for humanity than more of those large farms. I know you both are thinking about that. But is that part of the conversation among scientists, in general, who are thinking about this?

Anne Biklé:  I mean, I think [for] a lot of us who are looking at ways of addressing current problems in the food system, yes, this is very much on our minds. I think it gets tricky when we try [to] quantify things too much, in part because microbiomes, whether in the soil or the body, are really complex and dynamic. This is the problem with soil health. People keep coming up with different parameters and metrics to define what’s good soil health [and] what’s bad soil health, and it gets you so far in terms of characterizing the direction that we all want things to go and the final nutrient density qualities in our plant and animal foods. I like to think about it another way, and there’s probably a way of quantifying it, but it gets at the biotic integrity of the system. If there [is] somebody out there listening, here’s what we need. We need an index of biotic integrity around how well our soil is functioning, how well plants are communicating with their microbiome, [and] how well animals are communicating with their microbiome, because we want high, high biotic integrity. When that process is in place, then we know that nutrient density is where we want it to be.

It allows us to move a bit away from, to your point earlier, let’s check vitamin C levels, vitamin B levels, [and] phytochemicals. You can go down the rabbit hole on any one nutrient, but what you sort of lose from that is, how does it all fit together? You also lose sight of, if we can get these processes in place that are, back to my point about normal and functioning, then we’re getting the quality of foods that we need in the human diet for health throughout the lifespan. I think I remember that study, and I’m like, “Oh, great, everyone’s really going to want to start eating brain and liver again.” I happen to like liver, chicken liver, in particular, a lot.

Chris Kresser:  I’m not holding my breath on that one, based on what I’ve seen.

Anne Biklé:  Yeah, I know. That’s a really interesting study for another reason, Chris, because I think what it’s showing us is that animals, especially these herbivores, [are] able to extract things out of their diet [and] utilize their own biology to turn out this incredibly nutrient-dense tissue. Or in the case of ruminants, milk. That goes to show that there’s some pretty profound linkages and connections between these different sorts of biology. A plant is completely different than an animal, and yet, these animals are able to take in energy and all these other compounds and molecules, and it’s this alchemical transformative thing that’s like, “Wow, why would we not be considering these kinds of foods, given the health conditions that we’re facing today?”

Chris Kresser:  That’s right. And they do certain things better than we do. For example, they convert [vitamin] K1 into [vitamin] K2 more efficiently than we do. They convert beta-carotenes into retinol, the active form of vitamin A, often better than we do. It’s, in some ways, like, let’s let them do some of the work so that we don’t have to do all the work.

I want to go back to something you hinted at. There’s this concept [by] this food philosopher in Australia [named] Gyorgy Scrinis, and he coined this term, or he popularized, at least, in the scientific literature, food synergy. The concept there, which you just spoke to, is that nutrients don’t exist in isolation. They exist in an ecosystem, both in the soil and also later in our bodies. We know, for example, that you need magnesium to absorb and activate vitamin D. There’s actually the flip relationship there, too. Vitamin D is necessary to activate magnesium.

So if you’re focused myopically on a single nutrient, you may be missing the complex and important relationships that occur between these nutrients that are vital to our health. Another one I just did a video about is calcium. It’s one of the few examples where I think the [Recommended Dietary Allowance] (RDA) is too high. The RDA for calcium is based on the premise that people are deficient in vitamin D, vitamin K2, and magnesium, among other things. And yes, if that’s the case, you do need probably 1000 milligrams of calcium per day, which is what the current RDA is. But studies have shown [that] if you’re getting optimal amounts of [vitamin] D and [vitamin] K2 and magnesium and silica and all the other nutrients that support healthy bone formation, you could probably get 600 [or] 700 milligrams of calcium a day and be just fine. So it strikes me that you’re pointing at this whole complex interplay of nutrients that happens, and we need to be focused on that because there’s so much of it that we don’t even understand yet. We’re like monkeys with computers, barely scratching the surface of understanding this stuff. If we get too focused on any one single nutrient, we’re probably missing the bigger picture.

Anne Biklé:  Absolutely. We’re all after the same outcome, Chris. We want higher-quality food because we know that the human diet is incredibly important to human health. If we can get these processes in place, then we get to the outcome that we want without going down a million and one rabbit holes that ignore the food synergy picture that you just laid out for us. We think about symbiotic relationships a lot. These are the beneficial relationships between an organism and, as one example, their microbiome. And it made me think about [that] there [are] these symbioses between foods and compounds and molecules. What we want [is] to set those symbioses up because they’re mutually supportive, and it’s a way of getting at that without driving ourselves crazy trying to understand each and every intricate little detail.

That kind of stuff is really good when you’re first learning about something because it helps you understand larger patterns. But once we get the larger pattern in place, which, as an example of that, soil health, we need to be working on soil health and agriculture, then we can come up from the mechanistic reductionist things and go, okay, we’ve got the broad outlines of this thing right. Now, let’s work on policies and practices that get us to that outcome because we’re pretty assured that we’re going to get 80, 90 percent of that process back in place that gives us that outcome we’re looking for.

Chris Kresser:  Yeah, I think that’s super important. As I’ve continued to learn in my career as a Functional Medicine clinician, that’s the same way I approach human health at this point. There’s this complex interplay of interactions, and there’s a real risk in becoming too hyper-focused in any one particular area, whether that’s diet or exercise or sleep or stress management. Because health is way more complex than that. Good news, bad news, right? It explains, in my mind, how people can follow totally diverse approaches to health and have totally different results, because of this complexity and nuance that’s happening all the time.

Regenerative Farming as a Solution

I want to switch gears now and talk a little bit more about a solution, or the direction toward a solution, if you will, which is regenerative farming. First of all, for listeners who are not as familiar with that concept, how would you define regenerative agriculture [and] regenerative farming?

David Montgomery:  Well, we look at regenerative agriculture as systems of agricultural practices that enhance and build the fertility of the soil and are capable of maintaining it over time as a consequence of intensive agriculture. It’s basically agriculture that doesn’t degrade the soil [and] doesn’t degrade the land. [That’s] one way to think about it. There [are] lots of arguments as people try [to] spin up certifications and think about who is regenerative and who is not regenerative. There [are] arguments over what the term actually means. We tend to adopt the broadest view of that. If it’s building soil health, that’s regenerative. And there [are] different ways to do it. There [are] different paths toward that outcome. When you look at the [type] of farming practices that it takes to be regenerative, what we’ve come up with, in visiting farms around the world and interviewing farmers and reading as much of the scientific literature as we get our hands on, which is a lot, there’s something like a thousand references in the source document for What Your Food Ate, [and] there [are] three basic practices that you can think of as things that need to be done to be regenerative. [One is] minimizing disturbance of the soil. That’s minimizing plowing and minimizing agrichemical use. There’s keeping the land covered with living plants. That’s planting cover crops in between plants. No tilling, [and] no bare fallow. Always keep something growing because that helps feed the microbes. And grow a diversity of crops. That could either be a diversity of cover crops with a few cash crops or it could be a complex rotation of cash crops. There [are] different ways to do it. With some of the subsistence farms in Africa that we visited, it’s a very diverse set of entirely edible crops, with eight to 10 different crops in the same field, at the same time. There [are] lots of ways to get diversity. But [minimizing] disturbance, chemical and physical, [maximizing] the time duration of living plants in the land, and [growing] a diversity of plants is really the recipe for cultivating the beneficial life forms that can help build soil organic matter and support the nutrient cycling at the heart of what we’ve been talking about.

There’s one additional element that some regenerative farmers do and others don’t, and that’s reintegrating animal husbandry into operations. There [are] large-scale regenerative grazing operations that aren’t really doing cropping, but they’re growing diverse pastures. So there [are] different ways to do it, but those are the broad outlines as we see it. I view the challenge of rebuilding the health and fertility of the world’s agricultural lands as a pretty fundamental global infrastructure project for humanity to grapple with in this century. It’s the climate, fresh water provision, [and] healthy, fertile soil. Those three things are things that our future generations are going to need and that we can see paths toward providing. The soil is the one we’re mostly engaged on, but there [are], of course, links between that and water and the climate, as well. These aren’t isolated systems.

Making a Change in Our Farming Practices

Chris Kresser:  What’s your sense of where we are, in terms of our current status of the soil and how much time we have to figure this out and make change? I don’t want to put you on the spot here, but I’m going to put you on the spot here. With climate, of course, we hear a lot of different ideas on the whole spectrum. So with soil, where are we? I’ve seen some pretty dire statistics that are, frankly, quite scary in terms of the current status of topsoil and what’s going to happen if we don’t turn that around quickly. I’m curious what your sense of that is?

David Montgomery:  I view it as a slow motion disaster. The second part is the truly worrying part. The first part is where a little bit of optimism can creep in because if it’s happening in slow motion, we have time to maybe turn that ship around. I’ve seen regenerative farmers restore the fertility of their land in a decade or two, which to me as a geologist is incredibly fast. I’ve seen Anne restore the soil organic matter in our yard even faster than that. So the potential to turn it around is both immediate and real and could be done fairly quickly. The challenge is getting people to start doing it. That’s the social part, [and] that’s going to be the real challenge, I think. We know a lot about the methods and mechanisms for doing it. The good news on the soil end is I think that we have decades to get it right. We need to get it right this century; we don’t have beyond 2100. It’s similar to the climate, and we need to deal with it now, in this century. I think the change in the global agricultural system from what we now call conventional to what we now call regenerative agriculture is doable over the next 20, 30, 40 years. A few decades, we could do it. I think the stars are aligning that it makes a lot of sense economically for farmers. It makes sense for the ability to continue provisioning the world with food. It makes sense for our own individual health [and] with the choices that we make as consumers. So I think there’s the potential for a lot of growth in that area.

When I wrote Dirt back in 2007, the book that started Anne and I off on thinking along these lines, nobody was talking about soil health. It was not really a thing. Now you go to farming conferences and that’s what everybody wants to talk about, because farmers are looking for a better way to do things, because the conventional ways aren’t working out well for them on a number of levels I’d be happy to talk about. I think that if you look globally, we’ve degraded about 50 percent of the world’s soil organic matter and agricultural lands. In the [United States], that number is about the same, roughly 50 percent. We’ve drawn down the batteries that feed us by about half. We need to recharge the batteries. I think we can do it with a focused effort. Globally, something like only about 3 percent of the world’s farmland is practiced regeneratively with all the principles that I mentioned earlier. But there’s been a lot of big movement toward no till; there’s a big movement now toward cover crops. The challenge is getting people to integrate all three elements and then those who are interested in reintegrating animal husbandry to get the regenerative grazing practices back [in] play, as well. So there’s a lot of work to be done, but interest is growing, and I think there’s cause for optimism to look for increasing adoption because, frankly, it just makes sense, and we need to do it this century. It’s like the climate issue. There’s no advantage to waiting.

Anne Biklé:  The only thing I would add is that we have technology that already exists. It’s been in existence for millions of years, and that is plants and photosynthesis. While there are other things to throw at climate change, other technologies, people want to build carbon capture things, okay, go do that. But in the meantime, I think photosynthesis and the ability of crops, as well as wild plant communities, to pull carbon out of the atmosphere and get it down into the soil and store it as life that’s constantly cycling, that is a really positive thing. We already know it works. And what’s really interesting about when you start changing these practices and getting more carbon back into the soil, [is that] it doesn’t take 50 years for this to happen, Chris. You talk to any farmer or gardener who has begun to implement these regenerative practices, and within a couple [of] growing seasons, they’re saying, “Wow, I’m seeing that dark layer form on the top.” And there’s all these silver linings. Less pest and pathogen problems. In the case of farming, we hope, better nutrient density. There’s really a lot to be said for moving in this direction and achieving some of the things that we need to on the climate front.

Chris Kresser:  This is totally anecdotal, but 10 [or] 15 years ago, I didn’t know any young people [who] were going into farming, or not many. But now I know a lot. I have a close friend of ours, her daughter is in her late 20s, and she is so on fire about this and is looking for land and is ready, studying, [and] has done lots of internships with regenerative farms. And she has a whole bunch of friends [who] are moving in that direction. It strikes me that if we’re going to have more small farms, we’re going to need more farmers to be working those small farms. I’m just curious if you’ve seen that evolution over the course of the past 20 years.

Anne Biklé:  For sure. No doubt.

David Montgomery:  Oh yeah. The students at the University of Washington, where I teach, started a student farm about 10 [or] 15 years ago. We don’t have an [agriculture] program; we don’t have a soils program. There’s no real reason we ought to have a whole lot of students on campus who are wanting to become farmers and are interested in agriculture. But we do. And that has really grown in the last couple of decades. I think there’s a lot of young people who are very enthused about doing something very positive in the world with a different approach. One of the best things that we could do as a nation, I think, is to figure out ways to help young farmers get on the land doing regenerative practices. That could come in the form of subsidies, it can come with more loans, apprenticeships, all kinds of different things. But farming is a high capital business. Land ain’t cheap. And it’s a low-margin business. The returns aren’t spectacular by Silicon Valley standards. I used to go to farming conferences, and even in my 50s, I would be one of the youngest people in the room. Now, that’s starting to change. I’m obviously older now, but the people coming to those kinds of conferences are [younger]. There’s more and more young people interested in it as a lifestyle, as a business, as a way to support a family. As a nation, we ought to be doing everything we can to support young farmers in getting into the business.

Anne Biklé:  I think one of the most positive things [was] seeing one of the farms that we visited for What Your Food Ate has a really robust internship apprentice-type program where they bring young people onto the farm. It works really well with a no-till, vegetable farm where the acreage is not vast. This particular farm, they’ve got maybe three or four acres. It’s under really active production, and they’ve got about maybe six [or] eight interns. When we visited, these kids were busy. They’re outside. They like that. They’re not behind a screen; they’re moving around. Physical activity is good. They’re eating really good food. Their social health, they’re commingling with all of the other folks. It’s a really good work setting, in some ways, for a young person who is looking to use not just their mind but their body, and to be able to combine that in a way that benefits the planet and hopefully translates into a better future. I can’t think of a better career opportunity, in some ways.

Chris Kresser:  Yeah, I think a lot of people, in general, and young people [especially], are looking for more meaningful work, work that connects them with the community, with the Earth [and] the land, that’s happening in real time with real people instead of behind the screen, in a cubicle all day. Not that there’s necessarily anything wrong with that, but there’s a lot of people for whom that’s not a satisfying existence. Having a more immediate intimate contact with the world they live in and the food they eat is really, like you said, it’s a calling. It’s something that really appeals to people.

What We Can Do as Individuals

We’ve been mostly talking about the different levels where change needs to happen. There’s a public policy level where we could incentivize, like you said, [supporting] people who are starting small farms in all kinds of different ways. We can make changes in the educational system to support that. Then we have the farmers themselves, who are already farmers. How do we support them? [It] could also be policy changes, economic incentives, more education, etc. What about an individual person who is listening to this podcast? [If] they are resonating with this [and] they understand the importance of all of this, what choices can they make that can help increase the nutrient density of the food that they’re eating and overall cultivate that biotic diversity and health that you talked about?

I’ll start it off with one question. There’s been a lot of emphasis on eating organic, which I think is positive. But one of the things I’ve often encouraged people to do is eat locally as much as possible. Because as soon as you take something out of the ground, it’s going to start losing nutrient value right away. So if it’s shipped for 2000 miles across the country, which is true for the average carrot, by the time you eat it, even if it was grown organically in an organic farm 2000 miles away, the nutrient levels are going to be a lot lower. What do you think the most important things are for individuals in terms of choices that they’re making?

Anne Biklé:  First of all, I think that we all need to talk about this more because any kind of change or action starts with some level of communication [and] information. From there, you can go the organizing route and on to the political route, if one desires that. But one thing, for somebody who’s really interested in this and wants to know more about this, I’d really encourage checking in with your local farmers market. Even if that’s already a regular practice of a person, a pretty interesting question to a farmer at the market would be to say, “Hey, I was listening to Chris Kresser’s podcast, and he talked a lot about soil health. Do you know what that is? I just learned about it.” And depending on what that farmer says, if they’re like, “Huh?”

Chris Kresser:  Go to the next one.

Anne Biklé:  Yeah, go on to the next one.

Chris Kresser:  Next booth.

Anne Biklé:  I talk all the time to farmers at the farmers market where we shop. Farmers are definitely one crowd that like to be talking about their farm, what happened this season, what happened this week, and it is a way for a consumer to get behind what the actual practices [are]. Once you start to get more and more of that sort of information and experience, you can start to talk with your friends, with your family, [and] with your co-workers about it. I think that’s really important to do, for the reason that you said. Even if something is grown organically, or for that matter, regeneratively, if it’s shipped too far, [or] been sitting around too long, it’s just not good. This goes to the point of scalability and small farms and thinking about not only animals but also crops that are adapted to the emerging new climate conditions out there. Whether it’s the drought in the west or all the rain in the east, we’ve got to figure out ways to [find] crops and animals that do best in those conditions.

So there is a lot to talk about. If we let farmers know that we’re interested in their practices because we understand that practices are a huge influence on the different kinds of nutrients, from phytochemicals to selenium to zinc, then farmers are going to, I think, start going, “A-ha, these people are getting cluey. They’re asking me questions that I want to know more about too.”

Chris Kresser:  Yeah, it’s got to make sense. It’s increasing demand on both sides of the equation. And also, of course, if someone’s inclined [to] growing stuff in your backyard, as you’ve done. My wife has taken a few permaculture courses, and I’ve been amazed at what is possible to grow on a small plot of land. It was admittedly a lot easier when we lived in Northern California than it is in Park City, where it snowed a foot on Memorial Day this year and it could snow tomorrow here in September. We have a very short growing season and we need a greenhouse. But even then, we’re a member of the local farm [community-supported agriculture] (CSA), and I’m just blown away by what they can produce in such a short growing season with greenhouses. So if people are oriented in that direction, there’s nothing like taking fresh herbs out of your garden or [a] tomato off the vine in your backyard. It’s just the taste. I don’t think I really tasted a tomato until I was 22 or 23, because what I had grown up eating [from] the store [was] those waxy, pale, tomato-flavored, water-texture things. So yeah, you can taste that nutrient density in the food; you really can.

Anne Biklé:  Oh, yeah. And to that point, once you do, we go into this in the book, we call it body wisdom. Once the body puts together a really positive flavor and taste, embedded in that is high nutrient density. So it’s like, I don’t need to read any freaking labels, right? Because the flavor and taste have taken care of that for me. I like that idea, and farmers understanding that idea and consumers understanding that idea.

Chris Kresser:  It makes perfect sense. That’s the evolutionary wisdom working there. Well, I’ve really enjoyed this interview. I loved the book. The book is What Your Food Ate, and tell everyone where they can learn more about it and pick up a copy.

David Montgomery:  Well, if people are interested in learning a little bit more about it, they could visit our website, which is Dig2Grow. We’ve got a brief synopsis of the various books that we’ve written, including the new one, What Your Food Ate. You can download the references for the source material in What Your Food Ate if you want to see all the papers that we read that you don’t have to [read] if you read the book, because we read them for you. In terms of getting the book, it should be available wherever books are sold. If you like your local independent bookstore, or whether you like Amazon, or directly from the publisher, W. W. Norton. If you Google What Your Food Ate, you’ll find a way to acquire it if you want. And if you want to acquire a signed copy, send us an email through our website; those emails [are] forwarded to Anne and [me].

Chris Kresser:  Great. I have to say I’ve really enjoyed the book. It’s accessible and easy to read and yet it’s not dumbed down. There’s plenty of technical data and interesting detail for people who want that. It’s also a great story of the history of soil and the role that soil plays in human health and well-being, and health of not just humans, of course, but all life on the planet. It’s very timely and a really great read. I definitely encourage everyone to go pick up a copy. Anne and David, thanks again for joining me, and thanks for all the phenomenal work you’re doing. [I’m] looking forward to the next book.

David Montgomery:  Thank you. It’s a pleasure to talk to you.

Anne Biklé:  Yeah, thanks a lot, Chris.

Chris Kresser:  All right. Thanks for listening, everyone. Keep sending your questions [to] ChrisKresser.com/podcastquestion. We’ll see you next time.

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