Lead investigator Matthew Feinstein, a fourth-year student at Northwestern University Feinberg School of Medicine, said an earlier Northwestern Medicine study established a correlation between religious involvement and obesity in middle-age and older adults.
By tracking participants' weight gain over time, the new study confirms normal weight younger adults with high religious involvement became obese -- rather than obese adults becoming more religious.
"We don't know why frequent religious participation is associated with development of obesity, but the upshot is these findings highlight a group that could benefit from targeted efforts at obesity prevention," Feinstein said in a statement.
"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 research is being presented at the American Heart Association's Nutrition, Physical Activity and Metabolism/Cardiovascular Disease Epidemiology and Prevention scientific sessions in Atlanta.
Celebrity Couples of 2014 [PHOTOS]