“Not eating edible weeds is food waste. On farms, these plants are watered and fertilized accidentally, picked deliberately, then composted or discarded. They volunteer in yards, in parks and public spaces, on UC campuses, in edible schoolyards, and so on, and our typical response is a futile attempt to eradicate them, often resorting to chemical weapons that harm soil, water, pollinators, and so on. These plants, and foraging, remain traditional in many places, including the Mediterranean, mesomerica, and the far East.”   – Philip Stark



Philip Stark is a professor of statistics at UC Berkeley. His research centers on inference (inverse) problems. The applications of his research include the Big Bang, causal inference, the U.S. Census, climate modeling, earthquake prediction and seismic hazard analysis, election auditing, endangered species stressors, evaluating and improving teaching and educational technology, food web models, health effects of sodium, geriatric hearing loss and the seismic structure of Sun and Earth. Methods he developed for auditing elections have been incorporated into laws in California and Colorado. Stark has also published software. His research interests also include nutrition, food equity and sustainability. One of his research questions? Whether urban foraging could contribute meaningfully to nutrition, especially in “food deserts.” He is currently investigating wild foods in the East Bay.

Dr. Stark’s work is featured in “Take a Walk on the Wild (Edibles) Side,” the first in California Matters, a video series hosted by noted author and chef Mark Bittman. The video follows Philip Stark and Tom Carlson as they collect edibles in their urban area. They hope to boost awareness about urban foraging and the nutritional value of wild edibles found throughout neighborhoods in the East Bay.

ASA Fellow Philip B. Stark
ASA Fellow Philip B. Stark


Q: You and your colleague Tom Carlson have emerged on the vanguard of urban foraging. Your work has really captured the public’s imagination. How is urban foraging informing your ideas about community food resiliency? Does it have the potential to be scaled up in a significant way?

A: I’m a newbie; there are people who have been promoting urban foraging far longer than we have. I can’t explain why we’re getting so much attention, but I’m grateful for it, because it gives us a chance to increase public awareness of the underlying issues and the benefits of invasivory — eating invasive alien species.

Yes, this scales. Once you learn to identify a few invasive, non-native edible species, it opens your eyes: these volunteer foods are virtually everywhere. They have been part of human diet for thousands of years. They grow without being planted or watered. They grow in food deserts, industrial zones, urban and suburban yards, medians, community gardens, parks, urban farms, and commercial farms. In the areas we’ve surveyed — and in most of the world — there’s enough food volunteering to make a meaningful difference to the nutrition of local residents. Wild greens are not a large source of calories, but they are a great source of phytonutrients and dietary fiber.

Re-introducing these plants into our diets could reduce the water and carbon footprints of our food system. It could improve drought and disaster resilience. It could increase urban and commercial farm yields. It could decrease the use of herbicides on public lands. It could improve soil health, decrease erosion, and nurture pollinators. And many of these plants are intensely delicious: far more interesting than the narrow spectrum of commercially cultivated greens, with flavors that range from mild to aromatic to tart to savory to bitter. Wild and feral greens are a cultural resource, part of our shared heritage as humans. Embracing them is a win for nutrition, for food equity, for sustainability, for resilience, for the environment, for our connection to the environment, for our palates — and they are essentially free. There’s just no downside.

Q: How might this work fit into the growing concern about food waste? What cultural impulses are driving the current interest in foraging?

A: Not eating edible weeds is food waste. On farms, these plants are watered and fertilized accidentally, picked deliberately, then composted or discarded. They volunteer in yards, in parks and public spaces, on UC campuses, in edible schoolyards, and so on, and our typical response is a futile attempt to eradicate them, often resorting to chemical weapons that harm soil, water, pollinators, and so on. These plants, and foraging, remain traditional in many places, including the Mediterranean, Mesomerica, and the far East.

Salad with plums. Image courtesy of Berkeley Open Source Food. This is a foraged meal.

Q: You are doing some important work in areas known as “food deserts.” Is there a more accurate term than “food deserts”? Are you learning things about the urban environment that surprise you?

A: The USDA considers an urban census tract to be a food desert if it has a poverty rate of at least 20 percent or a median family income not greater than 80 percent of the area median family income; and at least 500 people or at least 33 percent of the population live more than one mile from a supermarket or large grocery store.

Our work has flipped our perception of food deserts: we’ve come to see that in a very real sense, less affluent areas are food gardens compared with suburban areas where ornamentals displace the food that otherwise would volunteer. In the food deserts we’ve studied, nature provides fresh, nutritious, and delicious food — all you have to do is spend a few minutes foraging in front of your own home. In nearby, less challenged neighborhoods, you have to pay for food, travel further to find it, it isn’t as fresh, nutritious, diverse, or tasty, and it has a much larger environmental footprint.

Q: Your work is taking place in culturally diverse communities. What are you learning about these communities that is informing your work?

A: One of the most interesting things we’ve observed is how diverse these communities are generationally as well as culturally: attitudes towards food, gardening, foraging, and cooking, differ enormously from grandparents to parents to children, as well as by ethnicity and culture. On the whole, we’re getting the impression that willingness to forage — and even consuming store-bought green vegetables — has less to do with socioeconomic status and access than with cultural and generational differences. We’ve also been surprised by our survey results, which show that many more people recognize wild foods and eat them regularly than we had imagined, and that the vast majority of respondents would eat wild foods from a reliable source.

Q: What implications does your work in urban foraging and open food sourcing have for social justice? What would food justice look like to you?

A: To me, food justice would mean that everyone has plenty of fresh, nutritious, affordable food; that farmers, farm workers, and others in food production and distribution make a reasonable living; that nobody owns intellectual property rights to organisms that let them force farmers to buy their products; that our food system takes into account the welfare of generations not yet born by curating and improving the health and productivity of the soil and preserving agricultural biodiversity; that livestock are treated humanely; that the deck is not stacked against small and medium farms in favor of industrialized agriculture; that corporations cannot market junk food as food, using adjectives that create a misleading impression of the healthfulness of those “foods”; and that marketing junk food to children is illegal. I’m sure I could add a dozen more items to this list.

Q: Your background is in statistics and modeling. The range of your work is pretty stunning. Some of the applications of your modeling have been in food webs and climate. What about that work is significant to the larger context of what is occurring in the food system today?

A: I’m embarrassed to say I haven’t given it much thought. My work in ecology has been pretty limited: appraising the uncertainty in numerical models of climate change and the economic impact of climate change; the impact of commercial fishing on the California Red Abalone population; statistical properties of numerical models of food webs; and the influence of packstock use in Yosemite National Park on the Yosemite toad, a protected species. Urban ecosystems and agriculture are new areas for me. A large portion of my work addresses what I call “quantifauxcation”: assigning a arbitrary numbers to things, uttering some statistical mumbo jumbo (often with the distraction of a massive computer model), then pretending that since the output is quantitative, it’s meaningful. There’s a lot of quantifauxcation driving policy, including agricultural policy, food policy and climate policy.

Q: What lessons from the past are influencing your work right now? What can we learn from?

A: That’s a really big topic, but here’s a slice. Our work on urban foraging and wild foods is all about recovering things we as a species knew and did in the past: humans evolved as hunter-gatherers. Our work has not uncovered a single new edible species, nor are we trying to. The plants we are studying have been part of human diet for eons, and still are in many parts of the world. The Latin names of many of these plants contains “oleraceus” or “oleracea,” meaning “edible.” (Two of my favorite examples are Sonchus oleraceus, sow thistle, and Portulaca oleracea, purslane. Our culture has lost almost all connection to the source of our food, and almost all knowledge of the natural world and ecosystems in which we live. We’re trying to reverse some of that—and even that isn’t new: Euell Gibbons had a similar message in the 1960s!

Tom Carlson and Philip Stark. Courtesy of UC Berkeley Newsroom, Hulda Nelson.

Q: What advice would you give to someone beginning the practice of urban foraging?

A: Make a “white list” of plants you know are edible (and which parts) … Start with one plant you know is edible and make friends with it; bring some home for dinner. Don’t worry about plants you don’t yet recognize: they are “not food” for now. Gradually add species to your white list. Get some good books on foraging with lots of pictures (I’d recommend the work of John Kallas, Samuel Thayer, and Steve Brill, in particular.) Take time to enjoy your growing awareness of the environment and getting in touch with your inner naturalist. Set a goal of having something wild on your plate at least once a week. Before you know it, you’ll be able to find something wildly delicious to eat more days than not.

Q: What advice would you give to someone beginning to engage in the practice of ethical, intentional and environmentally aware eating?

A: Cook — from scratch. It’s fun and rewarding; it can be very fast and easy; it’s a great way to bond with family and friends; and you’ll know what’s in your food. Remember that food comes from the ground and from animals, not from packages: don’t buy processed food. Think about the consequences of your food choices, not only directly on your own body through what you ingest, but also on the environment. Make a sport of reducing your footprint: how little garbage can you generate in a week? Can you make do with a smaller trashcan? Are you composting everything you can? Can you buy your groceries on foot or by bike, instead of burning fuel to get them home? Think about where your food came from and how it got to your plate. Even if you are buying organics, can shipping something across the country, or across an ocean, be the right thing to do? Think about food “terroir” and the benefits of eating truly locally. Make food, and farmers, a financial priority: pay the extra few dollars for food raised ethically and cut corners elsewhere if you need to (e.g., cook more, including making coffee at home instead of buying a $4 coffee out). Don’t buy industrial meat — but eat all the grass-fed, pastured meat you want. Learn about the difference between organic and sustainable, and between cage-free and pastured. Get your hands dirty by gardening or foraging or both. Shop at the farmers market and take time to talk to the sellers. Read (I’d especially recommend books by Mark Bittman, Daphne Miller, and Michael Pollan).

Q: Everyone gets the drought question! The California drought impacts the nation and the world. What changes might it bring about in the nation in terms of thinking about what, where and when we produce food? Are there opportunities to be found in this crisis? What might the future hold for California, and agricultural production in the state?

A: We should decrease the artificial incentives to grow more grain than we need for food in the Midwest, where water is relatively plentiful, and the artificial incentives to grow high-water crops in low water areas like California. Mark Bittman’s recent article on water points out the shameful fact that, in effect, California exports enormous amounts of water, in the form of almonds and other high-water crops. If you’re looking to decrease your own water footprint, think about replacing your lawn with an edible weed garden: it can provide a surprising amount of tasty food without the need to water. We need to shift the aesthetic. A green carpet of St. Augustine grass is, frankly, nauseating to me now: it’s pointless waste of water that can only be maintained by using herbicides. An “English garden” of edible weeds is much more interesting, provides food, produces beautiful flowers, and feels rich rather than sterile.

Q: Shifting gears a little bit … you’re a researcher and a scientist. What would you want the public to know about public investment in scientific research and education?

A: Just do it. It works. More seriously, this question puts me in an obvious bind: you are asking me to justify my salary. Higher education and research go hand in hand, and that putting resources into both is good for our children, good for California, good for the nation and good for humanity. The UC system is truly a gem, and has had enormous net positive impact on the California economy and more generally promoting the public good. I hope the administration recommits to the California Master Plan. Our best-in-the-world public educational system is in a precarious position; society needs to re-invest, immediately.

Q: You’re kind of a technology wizard, and you use mobile apps (iNaturalist) in your work. Are these social technologies changing how you work? Broadly, can you share your ideas about citizen science?

A: I think crowd-sourcing, crowd-funding, and citizen science are great ways to get more people involved in exploring our natural world. So far, they haven’t affected my work very much, but I’m just getting my toes wet. Among other things, we at Berkeley Open Source Food put together a field guide to “The Bay Area Baker’s Dozen Wild Edibles” as a premium for people who donate to our project—and we’ve received donations from nearly 100 people, partly in response to outreach during Wild Food Week and public foraging walks we’ve led. My colleagues Tom Carlson, Kristen Rasmussen, Eric Berlow, and I hope to catalyze “flash mob” citizen science mapping of wild edibles in large pieces of geography, such as all of Berkeley or Oakland.

Q: What keeps you up at night?

A: I lose sleep over what industrial agriculture and industrial food are doing to public health, both directly — by marketing non-food as food, breeding the nutrition out of our food, and narrowing the diversity of our diets — and indirectly, through its adverse effects on the environment, including soil, our water supply, and the atmosphere. The solution to anthropogenic global warming isn’t for everyone to drive a Prius or a Tesla: it’s to revamp agriculture, to protect and restore the soil (including increasing carbon sequestration by using cover crops and reducing tilling), to stop feeding grain to animals that should eat grass and concentrating them in such small areas that we create highly toxic environments that necessitate using antibiotics prophylactically, and generally to embrace restorative and holistic practices. We need more no-till farms, more grass-fed cattle, and fewer feedlots. Maybe then we won’t need more and more dialysis centers.

Q: What might it take to get the next generation inspired to be concerned about food policy?

A: I think the next generation is more involved than my generation is. Ecological awareness seems to be on the rise, and I’m deeply impressed and inspired by the work of young people like my friend Ariel Greenwood, a herdess at Holistic Ag in Sonoma who is using controlled “bison style” grazing to reduce non-natives, restore perennials and savanna, improve soil, and sequester carbon—and producing beef as a byproduct.

Q: What must institutions do to effect change in the food system?

A: I wish I knew. A good start would be for institutions to know and report the entire history of any food they serve, from seed to farm to farming method to how the workers are treated to how the food was treated and traveled to where it is served; to commit to paying what it takes to serve sustainably farmed food that is as local as possible; and to pay their food workers a reasonable wage. Institutions could eliminate vending machines and the sale/provision of unhealthful snacks. Institutions could stop using herbicides and encourage the community to take and eat the wild edible plants. For instance, I’d love to see the UC system stop spraying weeds on campuses, and instead put up signs that say, e.g., “I’m Stellaria media (chickweed). I’m mild and crunchy, and I taste like spring. Eat me!”

Q: I’m giving you a super power. You can change one thing about the food system with that super power. What change would you make?

A: I would eliminate subsidies for corn and soy. That could have enormous cascading benefits by increasing the cost of production: feedlots would become less economical, in turn promoting more pasturing of animals; using corn and soybeans as industrial inputs would become less economical, shifting us away from high-fructose corn syrup and other highly processed foods; mid-sized farms would become more competitive, since economies of vast scale in industrialized monoculture apply less to other crops than to corn and soy; and it would encourage shifting the cultivation of water-intensive crops, such as almonds, from the deserts of California to the corn belt, where water isn’t as scarce, saving aquifers; and there would be more incentive to develop cellulosic biofuels rather than burning food.