Abstract Background During the Covid-19 pandemic the Dutch government implemented its so-called ‘intelligent lockdown’ in which people were urged to leave their homes as little as possible and work from home. This life changing event may have caused changes in lifestyle behaviour, an important factor in the onset and course of diseases. The overarching aim of this study is to determine life-style related changes during the first wave of the COVID-19 pandemic among a representative sample of the adult population in the Netherlands. Methods Life-style related changes were studied among a random representative sample of the adult population in the Netherlands using an online survey conducted from 22 to 27 May 2020. Differences in COVID-19-related lifestyle changes between Complementary and Alternative Medicine (CAM) users and non-CAM users were determined. The survey included a modified version of the I-CAM-Q and 26 questions on lifestyle related measures, anxiety, and need for support to maintain lifestyle ...