I read the story this morning, mulled it all day, and … still have no working theory for why this should be so. I could buy the potluck explanation if we were seeing a slightly elevated risk for obesity among regular churchgoers, but … 50 percent? Whose bringing the food to those potlucks? These guys?

“Our main finding was that people with a high frequency of religious participation in young adulthood were 50 percent more likely to become obese by middle age than those with no religious participation in young adulthood,” says Matthew Feinstein, the study’s lead investigator and a fourth-year medical student at Northwestern University Feinberg School of Medicine.

“And that is true even after we adjusted for variables like age, race, gender, education, income, and baseline body mass index,” he added…

“We didn’t look specifically at the potluck factor, but anecdotally, we know that oftentimes at these religious gatherings people will eat traditional comfort foods which are often high in fat and calories and salt,” says Feinstein. “But, again, that’s not something we looked at in this particular study.”…

Feinstein says while obesity appears to be an issue for religious people, previous studies have shown that the faithful tend to live longer, be less likely to smoke, and to have better mental health status.

The key caveat here: Most of the participants were Protestant Christians. Why you’d conduct a study of religious effects on body weight and focus mainly on just one sect of just one faith, I simply have no idea. Having a control sample of Catholics or, better yet, Jews or Muslims or Hindus would have gone a long way towards eliminating or confirming the potluck hypothesis.

Seriously, any theories? I’m stumped.