Meet affiliated faculty Rolf Halden

In this series, we’re sitting down with the Swette Center affiliated faculty to catch up on food systems, innovation, and what makes a good meal. See the rest of the series on our Food Systems Profiles page.

Read on for an interview with Dr. Rolf Halden, Director for the Center for Environmental Health Engineering at the Biodesign Institute.

How did you get interested in food systems issues?

My work is in sustainability and I examine societal activities to analyze where they conflict with the carrying capacity of our planet. From there, our team formulates recommendations for what we can do to improve our situation. 

Food, for better or worse, is an important driver of sustainability. It impacts everything, our health and the quality of our air, water, and soil. Food production and distribution has a big resource footprint, requiring large amounts of energy as well as land,  water and other resources. Therefore, food is a subject of continuous scrutiny within my work. Food systems are more complex than food itself though, and it’s interesting how the overall footprint of food can change depending on where and how it is produced and how far it has to travel to meet the end consumer. All of these things are part of the food systems analysis and jointly they inform our overall understanding of the impact of what we eat on the state of the planet and our health.  

Share a glimpse of your current research and how it applies to food systems transformation. 

My work related to food systems has two main directions. One is an analysis of the energy, water, and resource requirements that go into food production. Using that analysis, we develop recommendations of what we should be doing to be more sustainable. For example, we published a study on hydroponic production of salad greens that can be grown by either conventional agriculture or hydroponics. We crunched some numbers to gain a better understanding of how advantageous or disadvantageous hydroponics is, depending on the dimension we look at. A still underdeveloped aspect is how the dietary value of our food changes as a function of how it is grown (e..g, with or without soil). 

This brings us to the other direction of my research: how our behavior and food intake impact our health. We analyze what goes through people’s bodies by analyzing wastewater for dietary markers. These can be markers of meat consumption, vitamins, antioxidants, etc. We can also measure our body’s response to the intake of food at the population level. For example, we can measure hunger or stress hormones in wastewater which allows us to develop an understanding of the health of people relative to their dietary status. We do all of this by extracting specific biomarkers out of wastewater and linking them back to diet, health, and wellbeing. This approach is amazingly scalable, ranging from school and university campuses  to entire cities or even countries. 

One of the key challenges with studying food is that we make a lot of individual choices that, when scaled up to large populations, become unsustainable and harm our planet and ultimately ourselves. So a question first and foremost in my mind always is: is this behavior or solution sustainable at scale. For example, how much meat can we produce with free-ranging, grass-fed animals or what are the impacts of switching to hydroponics instead of sticking with conventional, soil-based agriculture. The big questions are: How far can this go? How many people can we reach by this? What are the unwanted side effects and collateral damage of food production? 

What’s an innovation in the food systems world that you’re excited about? 

I’m very excited about the hydroponic production of food products without soil. This is an up- and coming area, similar to aquaculture, another topic we study closely. Top soil is under intense pressure from agriculture, and climate change threatens to further erode and diminish fertile land. It is fascinating to think that we can produce food at a large scale without soil, possibly with an efficiency that is several times greater than production using conventional agriculture. Is this really possible at scale, what are the downsides? We are studying what new pressure points are being created by adopting this and other types of technology, such as aquaculture. If you don’t use soil anymore, where are nutrients coming from? How do you harvest them? What is the impact? How far do you have to transport the ingredients you need for this type of new agriculture? It also raises cultural questions. Human population growth was largely enabled by transitioning from a nomadic lifestyle to a stationary one supported by farming and the cultivation of land. Hydroponic systems are a very different way of producing food, with many ramifications for us as humans with respect to both the accessibility of food and how we understand our role in food production. 

There is dramatic change on the horizon, which can be good or bad. Typically it’s not just one side, but rather a mixed bag. It is really exciting to be a part of this transition into a whole new phase of modern agriculture. It’s a great time to work in food systems. 

What’s your go-to weeknight meal?

When my family of five gathers around the dinner table, caprese salad with balsamic vinegar reduction is a go-to staple, best enjoyed with freshly baked sourdough baguette.