American Diets Got Slightly Healthier at the Start of the COVID-19 Pandemic

When confined to their own homes, many Americans appear to switch to a healthier diet – that’s the main finding of a new study looking into the nutritional knock-on effects of the COVID lockdowns.

After comparing the grocery purchases of 41,579 households pre- and post-lockdown, the researchers from Penn State found that the quality of the average American diet improved by up to 8.5% and the diets’ food diversity improved by up to 2.6%.

These nutritional boons, however, quickly faltered in most households as the lockdowns receded. Nonetheless, average levels of food quality and nutrition still remained above pre-pandemic levels for most households six months on from the first lockdown.

The results were published in PLOS One.

Lockdown food – more than just banana bread

Prior to the COVID-19 pandemic, the average US diet was considered generally unhealthy; the population’s average Healthy Eating Index score was 59 (out of 100) between 2015-2016, according to the Dietary Guidelines for Americans.

Yet, around half of US food dollars are spent on food away from home. So, when the US lockdowns descended in March 2020 and people’s food choices became limited to their own kitchens, one research group at Penn State saw the perfect opportunity to find out just how healthy Americans’ cooking habits really are.

The researchers were well-placed to investigate the quarantines’ effects on nutrition, too; at the time of the first lockdown, the team was in the midst of a grant-funded project that asked how people would feed themselves after a global catastrophe, such as an asteroid strike.

“At first, the most impactful events we could study using actual, real-world data were hurricanes and other natural disasters,” said Edward Jaenicke, a professor of agricultural economics at Penn State’s College of Agricultural Sciences. “But then, along came the COVID-19 pandemic, and we realized that this event was an opportunity to study the closest thing we had to a true global catastrophe.”

Jaenicke and his colleagues analyzed data from the NielsenIQ Homescan Consumer Panel on grocery purchases, which includes 41,570 nationally representative US households. Data consisted of the quantity and price paid for every product each family purchased during the study period, which spanned from six months before a state’s first lockdown to six months after. Household spending data a year prior to a state’s first school closures were also taken into account.

“To establish causality, an individual household’s pre- and post-pandemic food purchases were first compared to the same household’s food purchases from one year earlier,” Jaenicke said. “This way, we controlled for the food-purchasing habits, preferences and idiosyncrasies of individual households.”

The researchers found that between March andJune 2020, depending on the specific US state, there were modest increases in Americans’ food diversity – defined as how many different categories of food a person eats over a set period of time.

The researchers also found larger, temporary improvements in diet quality by judging consumers’ grocery receipts against the US Department of Agriculture’s Thrifty Food Plan.

Food diversity rose as much as 2.6% in the first few months of the school closure period, on average, followed by small increases and then a leveling off. Food healthfulness increased by as much as 8.5%, on average, in the first months of the closure period, again followed by a gradual decrease.

Neither of these decreases dipped back to the poorer nutrition levels recorded prior to the pandemic, though.

These patterns were observed across households with many different demographics, although households on lower incomes, with young children and without a car showed smaller increases in food quality.

Midwestern households, on average, saw larger food quality increases than households from other regions; households classified as Asian ethnicity or “Other” ethnicity generally also demonstrated higher increases in nutrition.

The researchers posit several possible explanations for their findings, the obvious one being the reduced reliance on unhealthy restaurant cuisine. A less obvious explanation could be that the pandemic increased consumers’ focus on health and caused a shift in home shopping towards more diverse and healthy foods.

The closure of schools and businesses may also have led to many households having more time to cook and prepare meals than they had before.

“During the COVID-19 pandemic, dine-in restaurants closed, schools and school cafeterias closed, and many supermarket shelves were empty,” Jaenicke said. “Since about 50% of Americans’ food dollars are spent on ‘away from home’ food from restaurants and cafeterias, the pandemic was a major shock to the food system.”

The researchers’ findings may not be applicable beyond the US, however. Their paper notes that a study of how British household diets were affected by the pandemic found that the decrease in calories purchased from dine-in restaurants was more than compensated by an increase in calories purchased from grocery stores and take-out restaurants.

Reference: Simandjuntak DP, Jaenicke EC, Wrenn DH. Pandemic-induced changes in household-level food diversity and diet quality in the US. PLOS One. 2024. Doi: 10.1371/journal.pone.0300839

This article is a rework of a press release issued by Penn State. Material has been edited for length and content.