The COVID-19 pandemic has affected all aspects of our everyday lives. To investigate these behaviour changes, an online survey was conducted with 1’028 individuals (51% female) in Switzerland between June and July 2020. The questions referred in particular to the lockdown in spring 2020. We put specific focus on the pandemic’s impact on health-related behaviour, which includes food choice, physical activity and body weight management. For instance, participants reported whether and how their consumption of different foods changed during the lockdown. As a measure of healthy food choice, we chose consumption of vegetables and salad and in contrast, sweet snacks and alcohol consumption was used as a measure for unhealthy food choice. For physical activity and body weight, participants indicated whether it decreased, increased or did not change during the lockdown as compared before. In a next step, we investigated the influence of various predictors on health-related behaviour using multinomial logistic regression models. We find that the possibility to work remotely led to healthier food choices, that is, a reported increase in vegetable consumption and decrease in sweet snack consumption, but also to more unhealthy food choices and lifestyles, that is, a reported increase in alcohol consumption as well as an increase in sweet snack consumption. For weight change, the data indicated that individuals who worked remotely were more likely to gain or lose weight than individuals working from the office. Our findings demonstrate how individuals are affected differently by the pandemic and how complex the whole picture is. Further, these results are crucial in developing health recommendations for possible future lockdowns or health crises in general.