Light rail in Charlotte. Photo by Justin Ruckman, via Flickr. Click above to go to Flickr.

Hat tip to National Public Radio for this perfect lunchtime post: a study in Charlotte, N.C., found that one year after a new light rail line opened, train riders were on average six pounds lighter than those who drove in the same area, according to a new study in the American Journal of Preventative Medicine.

Excerpt:

The average estimated distance from a LRT station to a work address among LRT users was 0.35 miles. Using LRT could increase walking by approximately 1.2 miles a day, if one assumes that those using LRT to commute to work would walk to a bus stop to take to the local LRT station, and then walk from the destination stop to their work addresses. The estimate of additional walking induced by LRT use in the present study is close to what would be necessary to generate the average weight loss observed….The findings from the current study suggest that increasing the access to LRT transit for individuals to commute to work may help overcome some of the barriers to engaging in daily utilitarian exercise.

The study isn’t completely air tight — these things often are not. But it basically corroborates another wide body of public health studies that have associated the suburbs with lack of exercise and higher weights because everyone drives everywhere. The issue, of course, is whether people are willing to spend more time commuting, since driving is still quicker in many instances.