Physical activity, screen time and dietary behaviours in New Zealand adolescents prior to and following the onset of the COVID-19 pandemic

Background: Insufficient physical activity, high screen time, and unhealthy dietary patterns among adolescents may have worsened during the pandemic, but data are lacking. This study compared physical activity, screen time and fruit and vegetable intake in adolescents from Dunedin, New Zealand, 5–6 years before (Study 1) and during (Study 2) the COVID-19 pandemic. Methods: Adolescents completed an online survey as part of the Built Environment and Active Transport to School (BEATS) studies in 2014/2015 (Study 1; n = 1,266; age: 15.3 ± 1.4 years; 54.6% female) and 2021/2022 (Study 2; n = 819; age: 15.2 ± 1.4 years; 47.4% female). The proportion of adolescents meeting guidelines for physical activity (≥ 60 min/day of moderate-to-vigorous physical activity), outside school screen time (≤ 2 h/day) and fruit and vegetable intake (> 1 serving/day for both fruit and vegetables) was calculated. Data were analysed using multivariable linear and logistic regression modelling. Results: Few adolescents met recommended health behaviour guidelines. Compared to Study 1, significantly greater proportions of adolescents at Study 2 met guidelines for physical activity (16.7% vs. 23.1%; p < 0.001) and outside school screen time (13.3% vs. 18.3%; p < 0.001) while fruit and vegetable intake was not different (29.6% vs. 27.0%; p = 0.322). Compared to Study 1, average outside school screen time at Study 2 was lower on both weekdays (5.0 ± 2.9 vs. 4.6 ± 2.9; p < 0.001) and weekend days (6.9 ± 3.5 vs. 6.1 ± 3.6 h/day; p < 0.001). Reported frequency of consuming sweets was higher and soft drinks lower at Study 2 versus Study 1. Conclusions: Despite observed higher levels of physical activity and lower levels of outside school screen time during the pandemic compared to the pre-pandemic levels, few adolescents met health behaviour guidelines at both time points. Therefore, comprehensive health promotion that aims to improve physical activity levels, screen time and dietary patterns for adolescents is still necessary to prevent chronic health conditions adulthood.