ObjectiveThe importance of a healthy lifestyle in preventing morbidity and mortality is well-established. The COVID-19 pandemic brought about significant lifestyle changes globally, but the extent of these changes in the Brazilian population remains unclear. The objective of this study was to evaluate changes in lifestyle among the Brazilian general population during the first year of the pandemic.DesignThree consecutive anonymous web surveys were carried out: survey 1 (S1)—April 2020, S2—August 2020 and S3—January 2021.SettingBrazil.ParticipantsThe study included 19 257 (S1), 1590 (S2) and 859 (S3) participants from the general population, who were ≥18 years, of both sexes, with access to the internet, self-reporting living in Brazil and who agreed to participate after reading the informed consent.Primary outcomeLifestyle changes were assessed using the Short Multidimensional Instrument for Lifestyle Evaluation—Confinement (SMILE-C). The SMILE-C assesses lifestyle across multiple domains including diet, substance use, physical activity, stress management, restorative sleep, social support and environmental exposures. We used a combination of bootstrapping and linear fixed-effect modelling to estimate pairwise mean differences of SMILE-C scores overall and by domain between surveys.ResultsIn all the surveys, participants were mostly women and with a high education level. Mean SMILE-C scores were 186.4 (S1), 187.4 (S2) and 190.5 (S3), indicating a better lifestyle in S3 as compared with S1. The pairwise mean differences of the overall SMILE-C scores were statistically significant (p<0.001). We also observed a better lifestyle over time in all domains except for diet and social support.ConclusionsOur findings indicate that individuals from a large middle-income country, such as Brazil, struggled to restore diet and social relationships after 1 year of the pandemic. These findings have implications for monitoring the long-term consequences of the pandemic, as well as future pandemics.