The study, published in Nature Human Behaviour, examined 9,367,550 weekly shopping baskets collected from more than 30,000 US households between 2017 and 2022. This long observation period allowed the researchers to compare purchasing patterns before the pandemic, during the disruption of 2020 and 2021, and in the post-pandemic period. The researchers combined household purchasing data with county-level information on pandemic policies, including restrictions that influenced mobility and retail activity. They also used artificial intelligence-assisted nutrition profiling to classify the foods purchased and assess changes in dietary quality at scale.

The results reveal a striking reversal over time. During the early pandemic and periods of lockdown, households increased the share of spending directed towards less processed foods. Such a shift may reflect the unusual circumstances of that period. With restaurants closed or operating under restrictions, families prepared more meals at home, while disruptions to daily routines may have encouraged purchases of basic ingredients and foods requiring preparation. At the same time, consumers faced uncertainty over supplies, employment and access to shops. The study indicates that the initial movement towards less processed products was not a permanent transformation of the American food basket.

In the period after the acute phase of the pandemic, spending on ultraprocessed foods rose above levels observed before COVID-19. Ultraprocessed foods are industrial formulations typically made using multiple ingredients and additives, and are often designed to be convenient, highly palatable and shelf-stable. They include many packaged snacks, ready-to-eat meals, sweetened products and processed beverages. The findings do not mean that every household adopted the same diet, nor that all processed foods have identical nutritional effects. Rather, they show that the balance of household spending moved in a direction associated with greater reliance on heavily industrially formulated products.

One of the study’s most important findings concerns how diet quality is measured. The shift was especially clear when foods were classified according to the NOVA system, which groups products by their degree of industrial processing. However, the same divergence was less pronounced when researchers used nutrient-based measures, including the Healthy Eating Index and the Food Standards Australia New Zealand nutrient profiling model. These tools assess food quality through characteristics such as nutrients, food components and overall dietary composition rather than processing alone. A product can therefore be highly processed without fitting every definition of nutritional poor quality, while a minimally processed food can still be high in salt, sugar or saturated fat.

This difference between measurement systems is scientifically important because it shows that “healthy” and “processed” are not interchangeable terms. NOVA can capture industrial transformation and the role of convenience foods in modern diets, but it does not directly measure every nutrient or dietary benefit. The Healthy Eating Index is designed to assess alignment with dietary guidance, while the FSANZ model evaluates nutritional attributes used in food profiling. By comparing all three approaches, the researchers found that each describes a different dimension of food purchasing. The study therefore supports using processing-based and nutrient-based measures together instead of treating any single score as a complete description of diet quality.

The pandemic also altered the relationship between food spending and household socioeconomic status. In 2020, the spending gap between socioeconomic groups widened, suggesting that the shock affected purchasing power and food choices unevenly. Yet the researchers report that this difference converged after the pandemic. A different pattern then appeared: a nutrition gap emerged as higher-income households increased spending on less nutritious foods. This result challenges the assumption that greater income automatically produces healthier purchasing. Resources can expand access to fresh foods and health information, but they can also increase the ability to buy convenience products, restaurant-style foods and premium ultraprocessed products.

Some food categories showed effects that persisted beyond the most disruptive months of the pandemic. Prepared foods, frozen foods and carbonated beverages were among the categories associated with lasting changes. Their persistence may reflect habits formed during periods when consumers prioritised convenience, storage life and reduced shopping frequency. Frozen and prepared products can help households manage time and uncertainty, while carbonated beverages are often heavily marketed and widely available. The continued presence of these categories in post-pandemic purchasing suggests that temporary crises can accelerate changes in the food environment that remain embedded after restrictions are lifted.

Because the analysis used purchasing baskets rather than direct records of everything people consumed, it cannot establish precisely what each person ate or prove that the pandemic alone caused every observed change. Food bought in stores may be shared, wasted, consumed outside the home or combined with ingredients purchased elsewhere. Even so, the scale and duration of the dataset provide an unusually broad view of household behaviour. By linking weekly purchases with local policies and applying several nutrition frameworks, the researchers were able to distinguish short-term disruption from longer-term change more effectively than a snapshot survey could.

The findings carry a warning for public-health planning. Food policies designed only for the emergency phase of a crisis may miss the habits that persist after the emergency ends. Support for affordable fresh foods, clear front-of-pack information, healthier prepared and frozen options, and restrictions on the promotion of products with poor nutritional profiles could help make food systems more resilient. Interventions may also need to account for socioeconomic differences without assuming that higher-income households are automatically protected from unhealthy trends. The pandemic did not produce one universal dietary response; it exposed how policy, convenience, income and food formulation interact. Understanding that complexity may be essential for preventing the next crisis from leaving behind another nutrition gap.

Subject of Research: US household food purchasing behaviours, nutrition quality and socioeconomic disparities during and after the COVID-19 pandemic

Article Title: Short- and long-term shifts in food purchasing behaviours and nutrition disparities in the USA during and after the COVID-19 pandemic

Article References:

Hu, G., Lu, W., Soberman, D. et al. Short- and long-term shifts in food purchasing behaviours and nutrition disparities in the USA during and after the COVID-19 pandemic. Nat Hum Behav (2026). https://doi.org/10.1038/s41562-026-02547-9

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41562-026-02547-9

Keywords: COVID-19 pandemic, food purchasing, ultraprocessed foods, nutrition disparities, household diets, socioeconomic inequality, NOVA classification, Healthy Eating Index, food policy, public health

Ultraprocessed foods, as defined by the research team, are industrial formulations primarily composed of substances extracted or derived from foods, or synthesized in laboratories, rather than traditional whole food ingredients. These products are designed for convenience—ready to eat or heat—yet their composition frequently lacks nutritional quality and includes artificial additives. Common examples include sugary beverages, packaged snacks, instant meals, and processed meats. Over recent decades, UPFs have increasingly supplanted fresh and minimally processed foods in global diets, a shift that, as the study elucidates, bears serious consequences for population health.

The comprehensive nature of this study marks a significant advancement over previous research that often focused narrowly on specific nutrients or isolated dietary risks rather than whole dietary patterns. Eduardo Augusto Fernandes Nilson, DSc, the study’s lead investigator from the Oswaldo Cruz Foundation (Fiocruz) in Brazil, emphasizes that UPFs transcend traditional nutrient concerns such as high sodium, sugar, and trans fat content. The industrial processes queasiness UPFs undergo, along with the incorporation of numerous artificial substances—including colorants, flavor enhancers, sweeteners, and emulsifiers—create complex effects on human health that require a holistic assessment beyond single nutrient analyses.

Utilizing advanced statistical modeling, the researchers established a linear association between the proportion of UPFs in an individual’s diet and their risk of all-cause mortality. Their analysis reveals that for every 10% increase in caloric intake from UPFs, the risk of premature death rises by approximately 3%. This seemingly incremental increase translates into a staggering public health burden when scaled across populations with varying dietary habits. For example, Colombia, characterized by relatively low UPF intake at 15% of total energy, experiences an estimated 4% of premature deaths associated with UPF consumption. In stark contrast, high-consumption countries such as the United States and the United Kingdom, where UPFs represent over 50% of caloric intake, report premature death rates attributable to UPFs approaching 14%.

The implications of these findings are profound. In the United States alone, the study estimates that 124,000 premature deaths in 2018 were directly linked to the consumption of ultraprocessed foods. This figure highlights the enormous scale of mortality potentially preventable through dietary shifts and robust policy measures. The public health ramifications extend well beyond mortality; high UPF intake has been implicated in the etiology of at least 32 distinct diseases, including cardiovascular disease, type 2 diabetes, obesity, various cancers, and depressive disorders. The cumulative effect of these illnesses imposes a tremendous burden on healthcare systems and societies worldwide.

One of the key strengths of this study is its cross-national scope, which affords comparisons across countries with varying socioeconomic and dietary profiles. It sheds light on a worrying trend: while UPF consumption has plateaued at high levels in high-income countries, it continues to rise rapidly in low- and middle-income nations. This pattern suggests an emerging global health crisis as industrialized food systems proliferate in regions previously dominated by traditional diets. Dr. Nilson warns that unless immediate, evidence-based policies are implemented, the health consequences of rising UPF consumption will be felt most acutely by vulnerable populations in developing regions.

The study’s call to action is unequivocal. Regulatory and fiscal policies should be aggressively pursued worldwide to reduce UPF intake and restore healthier food environments. Such approaches include taxation of ultraprocessed products, restrictions on marketing—particularly to children—mandatory front-of-package labeling, and incentives to promote traditional dietary practices rich in whole and minimally processed foods. Policymakers are urged to consider these strategies within a broader framework of food system reform to counteract the overwhelming influence of industrial food production.

From a technical perspective, the research employed advanced data and statistical analysis methods, integrating population dietary surveys with mortality data to derive relative risk estimates and model preventable deaths. This innovative methodology enables a more comprehensive understanding of the complex interactions between diet and mortality at a population level. It sets a new standard for epidemiological assessments of diet-related health outcomes, moving beyond nutrient-centric models to embrace the multifaceted nature of food processing and consumption patterns.

The growing evidence from this and related studies is reshaping the scientific consensus on the health impact of ultraprocessed foods. It underlines a paradigm shift from focusing solely on nutrient intake to considering the degree and purpose of food processing as a critical determinant of health. This holistic perspective recognizes that the industrial nature of food production alters not only nutrient profiles but also bioavailability, gut microbiota composition, and systemic biological responses, all of which contribute to disease risk and mortality.

In summary, this pioneering study provides compelling, quantifiable evidence that the share of ultraprocessed foods in the diet is a significant driver of premature mortality across diverse countries. The stark variation between low and high UPF consumption settings emphasizes the potential gains in life expectancy achievable through dietary modifications and policy interventions. Urgent global efforts are warranted to curb UPF consumption, safeguard public health, and steer food systems toward sustainability and nutrition security.

As UPFs continue to dominate markets worldwide, this study reinforces the critical importance of preserving and promoting dietary traditions based on fresh and minimally processed foods. Health authorities, researchers, and advocates must collaborate to translate these findings into impactful public health policies and consumer behavior change, ultimately mitigating the preventable mortality burden attributed to ultraprocessed foods.

Subject of Research: People

Article Title: Not explicitly provided

News Publication Date: 28-Apr-2025

Web References:
American Journal of Preventive Medicine
DOI: 10.1016/j.amepre.2025.02.018

References:
Nilson et al., American Journal of Preventive Medicine, 2025

Image Credits: American Journal of Preventive Medicine / Nilson et al.

Keywords: ultraprocessed foods, premature mortality, dietary patterns, public health, food processing, epidemiology, preventable deaths, nutrition policy