This Is Not a Paradox

According a recent randomized study:

Prayers offered by strangers had no effect on the recovery of people who were undergoing heart surgery, a large and long-awaited study has found.

On the other hand, another study showed that:

Doctors discovered that overweight African-Americans who regularly participated in religious activities had lower blood pressure than their less-faithful counterparts - a finding that didn't surprise spiritual leaders.

(Seen via The Raving Atheist, who had his own explanation.)

In related news, a randomized test found that experimental subjects who had just walked a mile were no thinner than those who hadn't. On the other hand, people who walk regularly are thinner than those who don't. In yet another study, when a group of strangers were told to diet for somebody else, the intended beneficiaries did not lose weight. When they were told that they were being dieted for, they even gained some weight.