Just to take a really crude whack at the question, there's a consensus that exercise is good for people, though not necessarily about how much and what kind.
You should check out The Longevity Project, which suggests that conscientiousness and maintaining your social network contribute to longevity..
Dying or becoming severely physically/mentally ill is very likely going to significantly lower the output of your utility function, so it would probably be a very bad idea to ignore the low-hanging resources which can significantly extend the time for which you are alive and well. I have attempted to search LessWrong for a list of such resources, and haven't been able to find one.
Are there any books, websites, or posts that contain significantly low-hanging fruit in this area? If so, please list them in the comments below.