Dr. Willet's groundbreaking research explores the links between health and nutrition -- from cardiovascular to cognitive function --  in a way that confronts convention and gives way to new ideas on the role of food in overall wellness. His research on the possible link between dairy and  prostate and ovarian cancers could potentially change the way cow's milk is collected and dairy products consumed. In this interview, Willet discusses America's two different eating trajectories and his ideal food pyramid.