Move over Atkins. Step aside Scarsdale. The newest proven way to lose weight? Support public transport.

Researchers from the University of Pennsylvania, Drexel University and the RAND Corporation studied the community of Charlotte, North Carolina, before and after a new light rail system for commuting was installed. Residents who switched to public transit saw a significant reduction in body mass index, or BMI, a measure of fatness that takes into account both weight and height. The study found that a 5-foot, 5-inch woman would have lost an average of 6.45 pounds 12 to 18 months after starting to take public transit. Commuters using the new system were 81 percent less likely than non-users to become obese over time.

“Public transit systems can generate positive health impacts by encouraging greater numbers of users to walk to station stops and maintain more physically active lives,” said John M. MacDonald, PhD, the University of Pennsylvania researcher who led the study.