The man behind the transformation is Mick Cornett, a former television sportscaster who became mayor in 2004. Three years later he was flicking through a fitness magazine when he noticed his city had been given the unwanted accolade of having the worst eating habits in the U.S. and was prominent on a list of the nation’s most obese populations. This coincided with his own reluctant acceptance, after checking his personal details on a government website, that at almost 220 pounds he was obese.

“This list of obesity affected me as mayor, and when I then got on the scales it affected me personally. I have always exercised and I remember thinking that I did not eat between meals, yet I was eating 3,000 calories a day. As mayor people are always wanting to meet with you, so it was not unusual to have a business breakfast, then a lunch with someone, then a function dinner. And in between there can be events with snacks and cookies.”

Cornett’s response was to start losing weight by watching what he ate; today he is almost 40 pounds lighter. But he also began to think about the issue, wondering why America was ignoring such a massive problem. His eventual conclusion was that this was because no one had any real solutions to the crisis. At the same time, the mayor began to look afresh at the culture and infrastructure of his city, realizing how the extent of reliance on cars had alienated human beings from enjoying and using their own urban environments.

His first step was to challenge citizens to join him on a diet. Using his flair for publicity after 20 years in television, he announced that he wanted Oklahoma City to lose one million pounds. He made the annoucement standing in front of the elephant enclosure at the local zoo on New Year’s Eve, aware of the media focus on diets in the days after the festive excess. He persuaded a health-care magnate to fund an information website called This City Is Going On A Diet—and was relieved over the following days as local papers backed his campaign and the national media praised it.

Churches began setting up running clubs, schools discussing diet, companies holding contests to lose weight; chefs in restaurants competed to offer healthy meals. More importantly for the mayor, people across the city began discussing a crisis spiraling out of control. Almost one-third of adult Oklahomans are obese, while the state ranks among the worst in fruit consumption and has one of the lowest life expectancies in America. Diabetes rates nearly doubled in a decade. Perhaps most alarmingly, more than one in five children aged 10 to 17 suffer from obesity and almost one-third of pre-school infants are overweight.

Ashley Weedn, the medical director of a specialist child-obesity clinic that opened three years ago in Oklahoma City, told me they were seeing ‘incredible’ cases of four-year-olds with high cholesterol and children consuming five times the daily sugar allowance in soft drinks alone. “We are even coming across kids with joint problems usually associated with much older people because of the strain on their legs, which we are seeing as early as six. This can involve surgery because of the pressure on bones leading to abnormal growth, which can lead to misshapen limbs.”