A new study published in the Archives of Internal Medicine this week indicates that both brisk walking and bicycling are likely to make significant contributions to controlling weight gain in premenopausal women—but slow walking not so much.

“This helps make the case that we need better separated bike facilities in the U.S. because bicycling is an effective way for controlling weight gain,” said Anne Lusk of the Harvard School of Public Health, one of the authors of the study and also an advisor to the Boston Cyclists Union. “Bicycling has a better chance of controlling weight in all populations.”

The study, using a population sample of over 18,000 women from the 16-year Nurses Health Study II, found that of the respondents who walked, only 39 percent walked briskly, and statistically, those who increased that walking time by 30 min controlled weight better over time than did the overall average. A larger 50 percent of respondents reported walking slowly, and did not show significant weight control.

On the other hand, even though cycling intensity was not examined, cyclists increasing their riding time by 30 minutes a day fared nearly as well as the brisk walking group at controlling weight gain over the 16-year period, and of course far better than the slow walkers. The authors also note that this may be the first study to separate the benefits of cycling from those of walking.

This has far reaching implications for urban design, said Lusk, namely that the recent craze for improving public health by widening sidewalks and plazas may be less likely to cause weight control for the pedestrians they attract than would an extremely safe bikeway, like a barrier-separated cycle track.

Dutch planners have designed their wide, separated cycle tracks and other innovative bikeways with women and older cyclists in mind for decades, and, as other researchers have pointed out, that country’s far higher cycling rates (27% commute by bicycle in the Netherlands compared to .5% in the U.S.) coincide with a far more svelte population (10% vs. 22.5% in the U.S).

Perhaps it’s time American urban transportation planners take note. Bike lanes may be the low hanging fruit, but cycle tracks are the future.