Yet another study shows whole foods cut the risk of cancer. In this case, researchers at the University of California, San Francisco, found "reduced risk among adults who ate two or more servings of whole grains each day compared with those who ate less than one serving a day. They also noted about a 35 percent reduction in risk among individuals who ate the highest amount of fiber (26.5 grams per day or more) compared with those who ate the least (15.6 grams per day or less)."