You knew smoking and fatty foods were bad for you, but thanks to a huge 40-year study, we now know exactly how bad. Researchers followed 19,000 men, starting in the late 1960s. Those who were still smoking, had high blood pressure, and had high cholesterol—the three top killers of middle-aged men—lived to an average age of 73. Those with none of those three risk factors lived to 83. (More heart health stories.)