A new report co-authored by SFI External Professor Ross Hammond lays out several ways tools from complexity science could be applied in updating the USDA’s nutritional guidelines. (image: nrd/Unsplash)

The decision of what to eat, and how dietary choices impact overall health, has always been complicated. Although nutritional guidelines can often offer guidance, there is no one-size-fits-all approach to a well-balanced diet, with factors ranging from a person’s health status, cultural background, and access to resources like farmer’s markets or well-stocked grocery stores, to personal dietary preferences.  

“There’s enormous heterogeneity across people and across contexts,” says SFI External Professor Ross Hammond (Washington University/Brookings). “Making one-size-fits-all recommendations is difficult.” Given this complexity, nutrition is an ideal area to apply complexity science. In February, the U.S. Department of Agriculture released a commissioned report, which Hammond wrote with a team of other researchers, outlining specific ways that complex-systems science — or “systems science” in the report — could be incorporated in shaping the country’s nutritional guidelines.

The USDA’s Dietary Guidelines, updated every five years, offers advice on what individuals should eat and drink. But the impacts of these guidelines go well beyond the personal — they influence school lunches, federal food-assistance programs, and the food industry more broadly. “The Dietary Guidelines are the central source for all evidence-based nutrition guidance developed by the federal government and shape hundreds of billions of dollars of annual federal spending,” says Hammond.

In the new report, Hammond and his coauthors outline six main strategies for incorporating complex-systems science into nutritional guidelines and offer a roadmap for creating a more nuanced, multifaceted approach to shaping nutritional policies. One strategy suggests including systems-science experts in the development of dietary guidelines, allowing new kinds of evidence and analytical tools to be included in the process. Another proposes using computational modeling tools from systems science to inform how dietary guidelines are implemented; this process often includes a range of factors, including everything from our agricultural systems, supply-chain issues, and environmental considerations. “That is a deeply complex-systems kind of question, because you are invoking lots of different moving pieces,” Hammond says.

As Hammond notes, nutritional guidelines don’t exist within a vacuum, but rather are informed by a number of different social, cultural, and environmental factors. As a result, the number of Americans who follow the dietary guidelines is currently quite low, with the numbers remaining stagnant for decades. Systems science can offer insight into some of the main barriers that are preventing Americans from following dietary guidelines; provide more nuanced and flexible guidelines on diet to accommodate a wide swath of personal and cultural preferences; and identify potential strategies that can help move Americans towards healthier eating patterns.

“Rather than a one-size-fits-all recommendation, what if we were able to have personalized recommendations that would suggest which are the things you could do right now, that would be easiest for you, that would move you in the right direction?” Hammond says. “What is the one thing that you could do, that would really help?” Thanks to advances in systems science, we are getting closer to making this a reality.