Abstract
Globally, the COVID-19 pandemic altered adults' and children's lifestyles and habits, causing an increase in body weight. Adolescents are sensitive to habit changes and, because of their insufficient capacity to deal with the unexpected COVID-19 changes, were at greater risk of noncommunicable disease development due to the consequences of adopting unhealthy habits. The survey aimed to reveal the changes in nutritional status and lifestyle habits of school children in Croatia and to assess their nutrition knowledge and emotional state and feelings about COVID-19 lockdown. Self-reported data from 1370 school children aged 10 to 15 years were obtained to examine the influence of the lockdown on their nutritional status, lifestyle and emotional status, and to assess their nutrition knowledge. The study revealed that the COVID-19 lockdown has caused an increase in the proportion of overweight and obesity among Croatian school children who changed their lifestyle habits towards being less physically active, spending more time using screen-based media and revealing potential psychological distress. However, the schoolchildren had a high adherence to the Mediterranean diet assessed with the Mediterranean Diet Quality Index for children and adolescents KIDMED index and had good nutrition knowledge. Public health programs promoting a healthy lifestyle and involving the whole family, in a school environment, could provide children with a healthy adulthood.