I want to thank each and every person who chose to provide an answer to this question. Eating, exercise and attitude seemed to be the general consensus. I would like to add my 2 cents here if I may. I offer them here because of my experience and research.
1) Breathing - we cannot live without oxygen, air. Many of us live in an environment where he the quality of our air is unhealthy, but even where it is, we seem to take breathing for granted. It remains, for me, the primary health factor. It is the focus of my meditation and the benefit is incomparable.
2) Water - again, so very elemental to life, yet the quality of our water is becoming more and more of a health concern. On a planet 3/4's covered by water and also and element that comprises 70% of the human body, we are in jeopardy if we taint our water supply. Keep it clean, keep it flowing!
3) Gratitude - Of all of the attitudes, I opt for an attitude of gratitude. There just doesn't seem to be any positive frame of mind that does not originate in gratitude. The more, the healthier, for all of life is a gift. If that is true, then the only appropriate response is gratitude.
May each and every one of you experience the joy and peace of all that you dream and wish for.