Population trends in dietary patterns in Spain before, during and after the COVID-19 pandemic

Diet and lifestyle significantly influence health, and during periods of economic, social, or health-related instability, individuals are more likely to adopt unhealthy eating behaviours. This study aimed to evaluate changes in dietary patterns among the Spanish population during COVID-19 home lockdown, comparing them with data from the 2017 National Health Survey (NHS) and the 2020 European Health Survey in Spain (EHSS). This study is among the first to compare nationally representative data before, during, and after COVID-19 lockdown, enabling assessment of the persistence or reversibility of diet-related behavioural changes following a major public health crisis. A cross-sectional comparative analysis was conducted using food frequency questionnaire (FFQ) data from all three sources: the 2017 NHS (n = 23,089), a survey conducted during lockdown (n = 1640), and the 2020 EHSS (n = 22,072). Z-tests for independent proportions were used to compare adherence prevalence across the three cross-sectional samples, assuming normality due to the large sample size in all cohorts. The findings showed that adherence to nutritional recommendations decreased significantly during lockdown (p < 0.05), while the proportion of individuals consuming processed and highly palatable foods increased. Notably, during the lockdown, more than 97% of the population failed to meet the recommended daily intake for any of the food groups. The proportion of individuals consuming sweets, snacks, and fast food above recommended levels increased from approximately 30% before lockdown to 88% during lockdown (p < 0.05). Following the lockdown period, dietary habits largely returned to baseline levels; however, adherence to dairy (87.3% vs. 81.1%; p < 0.05) and cereals (96.8% vs. 89.2%; p < 0.05) decreased compared with 2017. In contrast, legume consumption remained high after the restriction period (76.1% vs. 86.2%; p < 0.05). Significant differences were observed between the periods before and during lockdown. Specifically, the consumption of fruits (+ 0.9%: p < 0.05), vegetables (+ 0.8%; p < 0.05), sweetened soft drinks (+ 2.6%; p < 0.05), sweets (+ 3.7%; p < 0.05), snacks (+ 0.6%; p < 0.05), and sausages/cold meats (+ 0.7%; p < 0.05) increased, whereas the intake of dairy products (- 6.2%; p < 0.05), cereals including pasta, rice, potatoes, and bread (- 7.6%; p < 0.05), meat (- 1.0%; p < 0.05), fish (- 2.1%; p < 0.05), eggs (- 2.9%; p < 0.05), and legumes (- 1.7%; p < 0.05) decreased. In line with these findings, the dietary diversity score (DDS) showed a marked reduction during lockdown compared with the pre-lockdown period, followed by a substantial increase after restrictions were lifted. These trends suggest that during crises, dietary quality tends to deteriorate. Although some dietary behaviours recovered after lockdown, the persistent decline in adherence to dairy and cereal recommendations, together with the high consumption of processed foods, highlights the need for public health interventions aimed at reinforcing dietary stability and promoting health during periods of crisis.