American diets may have become healthier and more diverse in the months since the COVID-19 pandemic began, according to a new study led by Penn State researchers.
The study, published in PLUS ONE — found that as states responded to the pandemic with school closures and other lockdown measures, citizens’ diet quality improved by up to 8.5% and dietary diversity improved by up to 2.6%.
Co-author Edward Jaenicke, a professor of agricultural economics in the College of Agricultural Sciences, said the findings provide a snapshot of what Americans’ diets and eating habits might look like in the near-total absence of restaurant and cafeteria meals.
“When restaurants closed, our diets became a little more varied and healthy,” Jaenicke said. “One post-pandemic lesson is that we now have some evidence that any future changes in restaurant spending, even those not caused by the pandemic, could improve the diversity and healthiness of Americans’ foods.”
Before the pandemic, researchers said, the average American diet was generally considered unhealthy. According to the Dietary Guidelines for Americans, U.S. eating patterns have remained well below the guidelines’ recommendations, with only slight improvements in the average population Healthy Eating Index score between 2005 and 2016.
Additionally, before the pandemic, the research team was in the middle of a grant-funded project that focused on how people would eat after a massive global catastrophe, such as an asteroid impact or nuclear war. In particular, Jaenicke’s team was tasked with investigating how consumers and food retailers might behave during such a disaster.
“Initially, the most impactful events we could study using real-world data were hurricanes and other natural disasters,” Jaenicke said. “But then the COVID-19 pandemic hit, and we realized that this event was an opportunity to study the closest thing we had to a true global catastrophe.”
For the study, researchers analyzed data from the NielsenIQ Homescan Consumer Panel on grocery purchases, which includes 41,570 nationally representative U.S. households. The data consisted of the quantity and price paid for each universal product code purchased by each household during the study period.
Data were collected both before the pandemic struck and after it caused schools, restaurants, and other establishments to temporarily close. Because states did not respond to the pandemic simultaneously, researchers designated each household’s post-pandemic period as the weeks after the date their county of residence closed schools in 2020.
Jaenicke noted that this allowed the team to demonstrate a true causal effect of school closures during the pandemic, which typically occurred around the same time that restaurants and other food establishments also closed.
“To establish causality, we first compared an individual household’s food purchases before and after the pandemic to the same household’s food purchases one year earlier,” Jaenicke said. “In this way, we controlled for the food purchasing habits, preferences, and idiosyncrasies of individual households.”
Researchers found that in the two to three months after schools closed due to the pandemic (March through June 2020, depending on the specific U.S. state), there were modest increases in Americans’ dietary diversity, defined as the number of different food categories a person eats over a period of time.
They also found larger temporary improvements in diet quality, meaning that the foods purchased were healthier. This was measured by a household’s adherence to the USDA’s Thrifty Food Plan, which was designed to meet the requirements of the recommended healthy diet under the Dietary Guidelines for Americans.
These patterns were found across households with different demographic characteristics; however, those households with young children, lower incomes, and no car exhibited smaller increases on these measures.
“During the COVID-19 pandemic, sit-down restaurants closed, schools and cafeterias closed, and many grocery store shelves were empty,” Jaenicke said. “Given that roughly 50% of Americans’ food dollars are spent on food ‘outside the home’ at restaurants and diners, the pandemic was a major shock to the food system.”
The researchers said there are several possible explanations for these findings. First, because other studies have found that restaurant food is generally less healthy than food prepared at home, the dramatic decline in meals consumed and purchased at restaurants during the pandemic could have contributed to an increase in the diversity and healthiness of food at home.
Second, they said it was possible that a global pandemic prompted some consumers to become more health-conscious and led them to buy healthier and more diverse foods. Third, because the pandemic caused widespread supply chain disruptions, it’s possible that when familiar products ran out, consumers opted for newer ones that led to greater diversity and healthiness.
Finally, school and business closures may have resulted in many households having more time to cook and prepare food than before, while others (such as those with young children) may have had less free time than before the pandemic.
Jaenicke said that in the future, further studies could be conducted to explore how different disasters affect shopping and eating habits.
Douglas Wrenn, an associate professor of environmental and resource economics at Penn State, and Daniel Simandjuntak, a research associate at Newcastle University, also co-authored the study.
Open Philanthropy helped support this research.