Surprising factors that may keep you thin

A recent study in the journal Lancet Public Health found that people living within a kilometer (a little more than half a mile) of physical activity facilities — including gyms, swimming pools and playing fields — weighed less and had smaller waists than those who didn’t. The difference was greater in women and those with higher incomes.

The study was observational, so it does not prove cause and effect, but it does reinforce the impact of the built environment, including city design, on body weight.
Other research has found that more walkable neighborhoods are also associated with lower weight.
The Lancet study also found an effect, albeit weaker, on proximity to fast food restaurants: Study subjects who lived 2 kilometers (1.24 miles) or farther from a fast food outlet versus within half a kilometer (a third of a mile) were slimmer, especially women.