The "Big Killers" in the developed world are strokes and diabetes (type 2).
Strokes and diabetes could largely be avoided through good nutrition and low calorific diets. Add exercise to that, but do not think that just because you run, you can eat anything you want - BIG MISTAKE!
The longest living people:
1. Good genes.
2. Lack of significant stress in life.
3. Happy family relations, and friends.
4. Good nutrition, with emphasis on vegetables, fruit and restricted meat intake.
5. Moderate exercise (running over 50 miles a week is not 'moderate.').
6. Good psychological outlook on life, with positive thinking. You lose points if you suffer from frequent depression which affects the immune system.