Danish researchers followed 55,000 middle-age, cancer-free Danes for an average of 10 years. Their analysis revealed that almost 25% of colorectal cancers could be prevented by following five simple lifestyle habits (not smoking; daily physical activity for at least 30 minutes; avoiding heavy drinking; eating a healthy diet; and waist-circumference control — i.e., less than 40 inches for men and less than 35 inches for women).