h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

what do you think is the one thing that contributes most to a long, healthy life?

The Mediterranean diet?

Too a great extent, the answer will likely depend on how long 'long' is. Would one consider 60 years a long life? 80? 90?

[Would you say that food is more or less of equal importance to exercise?]
I suspect that eating healthily, a combination of content and quantity, is better than exercise for good health. Many excercise-fit individuals have died because of diets that clogged, enlarged, or poisoned their organs.

[Maybe it is all in the genes and there's little we can do about it?]
It also depends on being able to avoid being shot, strangled, run over, or falling to one's untimely demise. But, failing that sort of life changing event, we are all subject to our genes. Once that is considered a given, the question is really what do we do WITH it?; and that's where moderation, diet, and exercise can still change the end result.

[Is it just a positive outlook on life?]
No, a positive outlook is no match for an failed liver, enlarged heart, or radiation sickness.

[Could it be having lots of children and grandchildren?]
This could be considered a type of longevity, the fulfillment of a desire for immortality; but I consider the argument specious. Long life refers to one's own life, not living through surrogates.

[What about a private health care policy?]
I can't tell you. It's private!

Anything else you can think of?

[Or is it better to just relax and not worry about it?]
Now we're back to quality or quantity. Do you want a really long life in which you must pay attention to your daily rituals and the details of your diet and excise? Or, do you want to get the maximum enjoyment out of life, regardless of how much you may have shortened it?
I suspect that most people would suggest the need for a balance, even if they don't agree on exactly where to put the balance point.

I'm not a proponent of really long life. I think it's overrated. I've had plenty, and expect to have a lot more; but, I'll be happy with the final result whatever it may be.