Town planners could help reduce obesity by designing living environments that encourage walking, research suggests.
Walkable urban areas of Ontario, Canada, have lower rates of obesity and diabetes than those that are harder to navigate on foot, the study found.
Scientists compared health data for adults aged 30 to 64 living in southern Ontario cities with a measurement of "neighbourhood walkability" ranked from one to five.
A total of 8777 neighbourhoods were included in the study.
Between 2001 and 2012, the prevalence of obesity and excess weight increased in less walkable locations but did not change significantly in those places with a higher walkability rating.
In 2001, the proportion of overweight and obese people living in areas with a walkability score of five was 43 per cent, compared with 54 per cent in neighbourhoods at the bottom end of the scale.
New cases of diabetes were also less common in the most walkable cities.
The findings are reported in the latest issue of the Journal of the American Medical Association (Jama).
Lead researcher Dr Gillian Booth, from the Li Ka Shing Knowledge Institute at St Michael's Hospital, Toronto, said in a Jama video interview: "It seems that neighbourhoods that are more walkable and are designed to make it easier to walk may actually help people to be more physically active.
"Rates of overweight and obesity were much lower in the most walkable neighbourhoods compared to less walkable ones and were actually stable over time in the most walkable neighbourhoods."
People were also more likely to cycle or use public transport than drive in highly walkable areas.
The walkability rating was based on population density, residential density (the number of homes in a given area), the number of walkable destinations such as shops, banks, libraries and schools, and street connectivity.
More research is necessary to determine whether the observed associations are causal, said the scientists.