Background. Peru has one of the highest infection and death rates in the world for the COVID-19 pandemic. The government implemented house confinement measures with probable consequences on lifestyle, particularly affecting eating habits, physical activity, sleep quality, and mental health. Objectives. The aim of this study was to assess the lifestyles, physical activity, and sleep characteristics, as well as changes in eating habits in a Peruvian population during the first wave of the COVID-19 pandemic. Methods. A cross-sectional descriptive study was performed. We analyzed Peruvian adults based on an online self-administered questionnaire divided into sociodemographic, anthropometrics, COVID-19 diagnosis reported, lifestyle habits, and frequency of consumption of foods. Results. During confinement for COVID-19, 1176 participants were studied. Of these, most reported weight gain (1 to 3 kg) and 35.7% were overweight. The lifestyles habits showed that 54.8% reported doing physical activity and 37.2% sleep less. The Peruvian sample presented a main meal pattern of breakfast (95.7%), lunch (97.5%), and dinner (89.1%). Likewise, eating habits before and during COVID-19 pandemic showed that vegetables (OR:1.56, CI95% 1.21–200), fruit (OR: 1.42, CI95% 1.10–1.81), legumes (OR:1.67, CI95% 1.23–2.28), and eggs (OR: 2.00, CI95% 1.52–2.65) presented significant consumption increase during social isolation, while bakery products (OR: 0.74, CI95% 0.56–0.97), meat, snack, refreshment, and fast food decreased in consumption. Other foods showed no significant differences. Conclusion. This study showed an important frequency of overweight and sleep changes. There was a slight increase in physical activity despite the social isolation measures and an increase in healthy eating habits; nevertheless, the majority reported gaining weight.