The catalyst for change in Oklahoma City was the moment when Mayor Mick Cornett realized he was getting fat.

It was all those damn business lunches. “Everyone wants to feed the Mayor,” he lamented. But then he looked around him, and noticed he wasn’t alone. Oklahoma City was one of the 10 most obese cities in America, with the highest density of fast food outlets. Not quite the stats you want to list on the marketing brochures.

So he came up with a plan. A challenge. In 2007, he launched This City is Going On A Diet, an initiative aimed at motivating residents to lose a collective one million pounds. This wasn’t just about helping people fit into their swimsuits for the summer—Cornett wanted to systematically break down a “culture of obesity.” So he called for fundamental changes. A 2009 referendum approved a one-cent sales tax to fund a 70-acre urban park, hundreds of miles of sidewalks and trails, a streetcar system, and health and wellness centers. Private businesses provided loans to create more walkable downtown streets and add bike lanes and recreation facilities. City officials spent $100 million to create Every school is getting a gym. With the new emphasis on exercise, city officials spent $100 million creating a world-class rowing and kayak center.

The challenge turned into a $777 million, 10-year effort to redesign the city’s infrastructure with physical activity in mind. And it’s working. By 2012, the city met its goal of losing a million pounds, and the changes will help future generations live healthier, too.

It is not a new idea that cities can make it easier—or exceedingly difficult—for people to be physically active. But a new report from the International Physical Activity and Environment Network (IPEN) revealed just how much urban planning can impact how much our bodies move. Published in the medical journal Lancet and shared in Reddit’s Science community, the global study of 6,822 adults showed that those who live in the most activity-friendly neighborhoods get up to 89 minutes more exercise per week than those in the least activity-friendly areas. The message in the findings: To combat obesity, start at the macro level.

Neighborhoods varied in socio-economic status, and the study used geographic information systems (GIS) to measure residential density, number of street intersections, public transport stops, number of parks, mixed land use, and nearest public transport points. Physical activity was measured with devices called accelerometers that participants wore around the waists for a week.

We’ve all heard how we’re becoming a slothful society. One in four adults are classified by the World Health Organization (WHO) as “insufficiently physically active.” Elementary schools are reducing or eliminating recess to maximize class time. Diabetes cases have quadrupled over the past three decades. But beyond health and wellness, the report cites other benefits to designing “active cities”—less crime, more productivity, better school performance, increased civic engagement, and reduced pollution and traffic.

“Cities that make physical activity a priority, converting existing spaces into active spaces, and design environments for people to be active will create a legacy of physical activity,” the report states. “These active cities will be better off by almost every possible measure.”

There’s no magic formula to creating an active city, and a plan for Cincinnati would look different than one for New Delhi, but the report has some standard recommend for all communities: more parks and trails, walkable community designs, more sidewalks and bike paths, better public transit, and schools and workplaces within walking and biking distance of students. Other innovative solutions include creating “pocket parks” (transforming small, unused pieces of land in urban areas into recreational spaces), installing dividers between cycle and automobile lanes to increase bike safety, keeping parks and athletic spaces open and well-lit at night, introducing car-free weekends and creating workspaces that enable physical activity (treadmill desks and walking meetings!).

It all starts with an understanding that for better health, we need better design.

When you live in an active city, you can feel it. Redditors commented on the new study with their own experiences.

See the full discussion in the original Reddit post.