Background: The COVID-19 pandemic significantly impacted dietary habits and lifestyles. The objective was to assess the perception of changes in body weight and lifestyle among adolescents in the Bío Bío region during the COVID-19 pandemic. Methods: A descriptive, cross-sectional study was conducted on a sample of Chilean adolescents. A survey addressing sociodemographic characteristics, perception of changes in body weight, dietary habits, physical activity, sleep duration, and screen time during the COVID-19 pandemic was utilized. Results: A total of 122 adolescents aged 14 to 18 years participated, with 64.8% being female. Forty-five percent perceived an increase in body weight. Fifty-nine percent reported that the quality of their diet was not healthy. A significant proportion reported an increase in consumption of cakes, sweets, junk food, and sugary beverages, while maintaining their consumption of fruits, vegetables, and fats, and reducing their intake of fish. Most adolescents reported a decrease in the time spent on physical activity and sleep duration, accompanied by an increase in screen time. Conclusions: The findings reveal adverse changes in the lifestyle of adolescents during the pandemic, affecting their dietary choices, physical activity, and sleep patterns.
