Background and aims: Cardiovascular disease (CVD) is the leading cause of death globally. Apart from established CVD risk markers such as cholesterol and blood pressure, CVD risk can be assessed by anatomical markers of the arterial wall structure, including common carotid intima-media thickness (ccIMT). While unhealthy dietary patterns and other unfavourable lifestyle choices are major contributors to CVD risk, healthy plant-based diets are associated with decreased CVD risk. In this context, lifestyle programmes may constitute an effective tool for empowering individuals to make healthier lifestyle choices, but the effectiveness of such programmes should be assessed in controlled trials. Thus, it was the aim of this thesis to assess the e...