Sedentary Behavior and Ultra-Processed Food Consumption Associated to BMI Changes in Brazilian Students During COVID-19.

Introduction: University students experienced significant changes in their routines with the implementation of remote learning during Covid-19 pandemic, including increase in sedentary behavior (SB) time and ultra-processed foods (UPF's) consumption, which may have influenced changes in body mass index (BMI).

Objective: To evaluate the association between the variation in SB time and UPF's consumption with the variation in BMI, before and during the pandemic, in university students.

Methods: This is a cross-sectional study, conducted between November 2020 and February 2021, with students from a public university of Southeast of Brazil, who answered an online questionnaire with questions regarding to the period before and during the pandemic. SB was assessed through questions about time spent on TV and electronic devices. A score of the frequency of UPF's consumption was estimated based on the Brazilian Food Guide. Self-reported information on height and body mass was used to calculate BMI.

Results: The sample comprised 3390 university students, with an average age of 28.7 (± 10.0) years. Among them, 65.4% were undergraduates, and 66.9% were women. SB time, UPF score, and BMI increased significantly during the pandemic, compared to the previous period. In this population, there was a significant association between increased SB time (β = 0.06; SE = 0.01; p < 0.001) and UPF score (β = 0.08; SE = 0.01; p < 0.001) with an increase in BMI.

Conclusion: Changes in SB time and UPF score were associated with an increase in BMI before and during the COVID-19 pandemic in students from a Brazilian University.