The aim of this study is to reduce breast cancer recurrence and hence increase disease-free survival through either a high intensity or a lower intensity lifestyle program that includes low glycemic index diet, physical activity and supplementation with vitamin D, for 33 months, in women living in Italy who have been surgically treated for breast cancer (either late stage or early stage but highly proliferative) within the previous 12 months. The objectives of the study are: to determine if the high intensity program is more efficacious than the lower intensity program in: 1) reducing breast cancer recurrence and 2) improving glycemic, hormonal, cardiovascular and cancer-related epigenetic markers.