Background: Lockdown due to COVID-19 influenced food habits and lifestyles with potential negative health impact. This study aims to identify patterns of change in eating habits and physical activity during COVID-19 lockdown in Spain and to identify associations with sociodemographic factors and usual habits. Methods: This cross-sectional study included 1155 adults recruited online to answer a 10-section questionnaire. The protocol assessed usual diet by means of a semi-quantitative food frequency questionnaire, usual physical activity (PA) and supplement use, dietary changes, sedentary time, PA, exposure to sunlight, sleep quality, and smoking during confinement. Patterns of dietary change were identified by factor analysis. Factor scores were included in cluster analysis together with change in PA. Results: Six patterns of dietary change were identified that together with PA changes during lockdown defined three clusters of lifestyle change: a cluster less active, a more active cluster, and a third cluster as active as usual. People who were usually less active were more likely to be classified in the cluster that increased physical activity in confinement. Scores of the Healthy Mediterranean-Style dietary pattern were higher in this group. Conclusions: Different patterns of change in lifestyles in confinement suggest the need to tailor support and advice to different population groups.

There is a need for an effective nutrition policy promoting healthy nutrition in accordance with the ongoing dietary guidelines.