As any good actuary will tell you, your best guides to life expectancy are when and how your grandparents/parents died. Diet and exercise help, of course, but the underlying health issues tend to be congenital.
I knew a chap whose father and brother both died of heart attacks in their 40s. Given which, he looked after himself scrupulously, exercised, barely drank and certaily never smoked or took drugs. Despite all this, he had a near-fatal clutcher when he was 48 and is now pretty much treading on eggshells waiting for the next one.
You can't beat genetics, I'm afraid.