Urban design and public health go together. Your neighborhood can help determine how well you are.

The secret is creating an inviting, walkable, playable neighborhood, according to Mark Fenton. It's key to curbing obesity and other chronic diseases that result from unhealthy lifestyles — common ills like heart disease, osteoporosis, diabetes and even depression.

Communities need to mix residential and commercial property, build lots of sidewalks and bike trails and even shortcuts. They should design sites that invite people to arrive by bike or on foot and think about safety issues, said Fenton, a walkability and fitness expert and author of books including "The Complete Guide to Walking for Health, Weight Loss and Fitness."

The biggest safety issue, particularly for kids, is not stranger danger. It's getting hit by cars when on foot or on bikes because of how things are designed and because of driver inattention. They stay inside in part because neighborhoods and communities aren't built so kids will want to go outside and play, Fenton said. Many don't provide "pocket parks" or bike routes or sidewalks. They don't encourage people to sit on the porch and visit or walk back and forth to friends' houses.

"If you and I walk every day to work on the street and neighbors get to know us, we're regular features, the streets become safer," he said. "Stranger danger is one of the outcomes of having abandoned the streets, the outdoors in general. It's not an inviting place anymore. The little park is not there. There's no corner store or ice cream shop."

Fenton and a group of neighbors in Boston started a walking school bus, where parents take turns walking a large group of children to school. The kids learn safety and who belongs on the street and where to go if something makes them nervous. They get exercise they desperately need. The more kids get involved, the less often a parent is the "bus driver."

The country is beginning to embrace the better-design message, Fenton said.

Policies are central to creating walkable, user-friendly outdoor areas. Subdivisions need to make rules that sidewalks are mandatory, separated by at least a three-foot planting strip from the street. The sidewalks themselves need to be wide enough for two people to walk side by side, he said.

And neighborhoods need to be connected to each other with sidewalks and cut-throughs so Johnny can walk over to Jimmy's house to play without having to use an arterial route.