He was 47 at the time and admits that he wanted to cry from embarrassment.

The battle against obesity across America, a country where 46 per cent of meals are eaten away from the home, is now his signature issue. He talks about it passionately, sends out before-and-after photographs and has written a bestseller on his own journey to thin (Quit Digging Your Grave with a Knife and Fork).

It was published, complete with a national tour and 12-stop programme “to end bad habits”, in June. Huckabee-lite, or “Skinny”, as President Bush now refers to him publicly, is also chairman of the National Governors Association, the organisation that represents the heads of all 50 states. And guess what? He is using the platform to drive forward a message for much greater emphasis on preventing people getting fat.

“I think it’s the No 1 issue that we face in terms of a domestic crisis,” he told me from the governor’s mansion, fresh from the early run, cycling and weight routine with which he starts every day. “The reason I say that is because this is the one issue which, if left unchecked, will eventually bankrupt the country.”

The growing cost of treating the obese is pushing up healthcare costs, he says, forcing firms to give up paying premiums for workers in a nation without much other cover. This, in turn, is making more and more people with the chronic, dependence illnesses that come from obesity fall on the state for help. “There is not a single governor who believes his or her state can sustain the growth of government health costs,” he says bluntly.

It is this pragmatic realisation that appears to be finally tilting the balance towards action and away from arguments about freedom of choice. There is a mountain to climb, though. The federal government, for example, spends about $48 million (£26.5 million) every year promoting good nutrition for children, which sounds high before a look at what McDonald’s, alone, spends on advertising: $665 million (£367 million).

But Arkansas, by an accident of its Governor’s health, has become the improbable crucible for tackling overeating across America, and perhaps even in Britain.

England now has the fastest-growing weight problem in Europe, with 25 per cent of children under the age of 11 overweight or obese, according to a report from the National Centre for Social Research and published by the Department of Health earlier this year. It indicates a threefold increase in childhood obesity in the past 20 years. Separately, the British Medical Association has said that 20 per cent of 13 to 16-year-olds are also overweight.

A National Health Service already fretting over how to care for the growing numbers of elderly now faces grappling with the novelty of treating the sick young. Obesity kills people, eventually, and the diseases it triggers, such as heart problems, strokes, cancer and diabetes, are among the most expensive to manage, while usually guaranteeing lives of stunted economic worth.

Still, on the bright side, at least things are not quite as bad as Arkansas yet, or a cluster of other southern states, where 40 per cent of children are now overweight, a generation passing straight from cradle to couch.

Type two diabetes, the direct consequence of being chronically overweight, was once confined to adults. In America’s South, they are finding it in children as young as eight (nine in London, incidentally).

“Here’s the tragic thing,” Huckabee says, a strain of the convert’s disbelief in his voice. “A kid who is diagnosed with type two diabetes as a pre-teen will have vision problems in his twenties, will have a heart attack before 30, renal failure and kidney shutdown by 40, and be on full dialysis.”

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