For decades, Americans have been advised that cutting fat was key for a heart-healthy diet, spurring an industry of low-fat dairy products. A new generation of nutrition research is challenging some of those long-held beliefs—suggesting that for dairy products, the overall effects of whole-fat varieties on heart health may be positive. A new study adds to this shift. Using data from more than 3,100 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study, researchers tracked dairy consumption and measured coronary artery calcification—a buildup of calcium in the arteries that can be an early sign of heart disease....