I've heard of people leading healthy lifestyles or eating a good balanced diet, and yet they still get it. Why does that happen? Is there a certain way of lifestyle that increases chances of getting heart attacks?

My uncle is a gym freak, only eats meat once a week and is the most healthiest person I know. But a year ago he got a heart attack -- he runs his own business and my aunt reckons that it has alot to do with his job and his overall control freak attitude. I read that too much stress does that to a person.