It is hard to know what to make of this dumbfounding statement. Either it is disingenuous, or it undercuts his whole project. The message seems to be that there is a great deal of evidence that belief in God would be good for you, but don't try believing based on that evidence-because it won't work. If you happen to already have had a genuine religious experience, then these are all the fringe benefits you can enjoy. As the disclaimer demonstrates, Koenig is aware of the problem of putting the cart before the horse, and the dangers of applying epidemiological data to treatment recommendations.
Spirituality is among the oldest, slipperiest, most subjective and most profound of human phenomena.
It is not subject to empirical verification or disproof and to subordinate it to our obsessive, narcissistic quest for personal health is petty. It is hard to imagine a surer sign of utter spiritual bankruptcy than a religious conversion, or even an attempted simulacrum thereof, based on a desire to cheer oneself up or eke out a longer life. S ren Kierkegaard is probably spinning rapidly in a cemetery somewhere in Denmark. We will probably never see books suggesting that people watch more television or have sex more often in order to enjoy greater health, as those are among the very few activities people seem willing to pursue for their own sakes. Sociologic and epidemiologic data seem to have limited relevance when it comes to making uniquely personal and existential decisions.