Uh-oh. All those pizzas luring young adults to church activities may have unintended consequences. The devil may be in the pepperoni: Folks who stick with church for years often wind up fatter than their unchurched peers.

Young adults who go to a religious event such as worship or Bible study at least once a week are 50% more likely to become obese by middle age as young adults with no religious involvement, according to new Northwestern Medicine research based on tracking 3,433 men and women for 18 years.

Researchers, who present their study this week to an American Heart Association panel in Atlanta, say they don't know if it's the pepperoni, the potato salad or maybe the sedentary nature of prayer that hits believers in the belly.

Matthew Feinstein, the study's lead investigator, speculated:

It's possible that getting together once a week and associating good works and happiness with eating unhealthy foods could lead to the development of habits that are associated with greater body weight and obesity."

The researchers caution that this doesn't mean religious Gen-Xers have worse overall health. Previous studies have shown religious people tend to live longer than those who aren't religious in part because they tend to smoke less. Other studies find churchgoers are happier because they have a network of close friendships through shared beliefs and activities.

If this finding sounds familiar, it is. In 1998, Purdue University sociologist Kenneth Ferraro determined by studying religion, health and Census data that the most obese people tended to be in the states with the highest reported religious involvement.

He found that although body weight was more affected by class, ethnicity and marital status ...

Baptists tended to be the heaviest, with Jewish, Muslim and Buddhist groups the least overweight.

Ferraro wondered if overeating was the indulgence pastors overlook -- unlike smoking, drinking and playing around.

Have things changed since then? Maybe not. Religion News Service reports that most evangelicals oppose government anti-obesity efforts.

Pew Center for the People & the Press found white evangelicals (56%) are the only major religious group who stand against first lady Michelle Obama's "Let's Move" initiative as a proper role for government.

Obama knows the power of churches. As RNS reports, she took the Let's Move anniversary event to an evangelical church last month.

The Rev. Rick Warren, the big man with the big California church, is leading his congregation on a well publicized diet.

THINK ABOUT IT: Is fat a faith issue?