Background Around 30% of post-menopausal breast cancer is related to excess body fat, alcohol intake and low levels of physical activity. Current estimates suggest that there is a 12% increased risk in post-menopausal breast cancer for every 5 kg/m2 increase in body mass index (BMI). Despite this evidence there are few lifestyle programmes directed towards breast cancer risk reduction. This paper describes the process of optimising of the ActWELL programme which aims to support weight management in women invited to attend routine National Health Service (NHS) breast screening clinics. Methods A feasibility study of a prototype programme aiming to change lifestyle behaviours was successfully undertaken. The programme used educational approa...