Positive Psychology at Work:

How to Have a Better Quality Old Age

• Eat real food, not too much, mostly plants.
• Exercise regularly: include aerobic, resistance, flexibility and balance exercise.
• Drink alcohol in moderation (this is probably some research aberration, but it is statistically better than not drinking alcohol at all).
• Don't smoke.

All things being equal, these four things make 14 years' difference to life expectancy, and, as importantly, the quality of life of those extra years.

Thanks to Raymond Fowler at the International Positive Psychology Congress 2009 for this useful distillation of the research.