Analysis of Association between Adolescents’ Food Habits and Body Mass Change in a Population-Based Sample: Diet and Activity of Youth during COVID-19 (DAY-19) Study

The COVID-19 pandemic may have contributed to food habit changes, including some negative ones that may increase the risk of overweight and obesity. The aim of the study was to analyze the association between adolescents’ food habits, body mass change, as well as physical activity level in a population-based sample within the Diet and Activity of Youth during COVID-19 (DAY-19) Study. The DAY-19 Study was conducted in a cohort of 1333 students (aged 10–16 years) recruited in schools after stratified random quota sampling of primary schools (sampling counties within voivodeships and schools within counties) in June 2020. The food habits were assessed for the period of the COVID-19 pandemic and the period before the COVID-19 pandemic while using Adolescent Food Habits Checklist (AFHC). The body mass changes were assessed based on body weight and height for the period of the COVID-19 pandemic and the period before the COVID-19 pandemic while using Polish growth reference values. The physical activity changes were assessed based on the subjective assessment of adolescents. It was stated that for female adolescents declaring body mass gain during the COVID-19 pandemic the highest AFHC purchase scores (healthy purchase habits) (p < 0.0001) were accompanied by the lowest AFHC consumption score (unhealthy consumption habits) (p < 0.0001), as well as for female adolescents declaring physical activity decrease during the COVID-19 pandemic the highest AFHC purchase scores (healthy purchase habits) were observed (p = 0.0333). It was stated that for male adolescents declaring physical activity increased during the COVID-19 pandemic, the highest AFHC consumption scores (healthy consumption habits) were observed (p = 0.0003). In the case of a majority of participants, the general food habits were unchanged, which was observed mainly for food habits associated with food preparation. More food habits changes associated with the COVID-19 pandemic resulting in body mass changes were observed in females than in male adolescents. Body mass gain during the COVID-19 pandemic in adolescents may have resulted from unhealthy consumption habits, accompanied by decreased physical activity, in spite of the fact that this sub-group presented healthy purchase habits, which was observed especially for female adolescents.