Dr. John M. MacDonald, a criminology professor and behavioral scientist at the University of Pennsylvania, wanted to know whether switching from driving to riding mass transit would help people lose weight. To find out, he surveyed Charlotte, North Carolina, residents who had become regular users of that city’s nearly three-year-old Lynx light-rail line.
What he found was that individuals who quit driving to work and instead rode the rail line walked an average of 1.2 miles each day when going to and from work. On average, after six months of rail commuting, they reduced their body-mass index by 1.18 points. For a person who is 5-foot-5 and weighs 150 pounds, that translates into a weight loss of 6.45 pounds. His results are published in the August issue of the American Journal of Preventive Medicine.
A 2005 study by L.M. Besser and Andrew Dannenberg found that American transit-riders average 19 minutes of daily walking to and from transit. Thus, increasing access to transit could significantly increase opportunities to be physically active. The study found that 29 percent of people walking to and from transit achieve the recommended 30 minutes a day of physical activity.
Rail users (more than bus riders) and minorities, households earning less than $15,000 a year, and individuals in high-density urban areas were most likely to achieve the recommended activity level by walking to transit. These groups include many of the people most likely to suffer from obesity.