The First Lady announced that the US president had not touched cigarettes for almost a year and could now be counted among the ranks of the 1.3 million of his compatriots who are estimated to kick the habit annually.
His final motivation – which followed years of pressure from his wife – was wanting to be able to look his daughters Malia, 12, and Sasha, nine, in the eye and say he did not smoke.
Mrs Obama revealed her husband’s achievement as she marked the second year of her campaign against childhood obesity, which she now wants to take around the world.
“He’s always wanted to stop,” said Mrs Obama, adding that once she knew last year that he was serious about quitting she had left him alone. “When somebody’s doing the right thing you don’t mess with them,” she said.
Mr Obama, 49, has confessed to picking up the nicotine addiction in his late teens, though his usage had dwindled to a few cigarettes a day by the time he launched his campaign for president in 2007.
One of Mrs Obama’s conditions for agreeing to a bid for the White House was that her husband gave up smoking, but despite “chewing Nicorette strenuously” he confessed to regularly cadging cigarettes from campaign aides.
Mr Obama himself last addressed the issue in June 2009. Before signing a tough antismoking law designed to keep millions of teenagers from getting hooked, the president admitted there were times “where I mess up”.
“I constantly struggle with it,” he said. “Have I fallen off the wagon sometimes? Yes. Am I a daily smoker, a constant smoker? No.”
A medical in March last year gave Mr Obama a largely clean bill of health but recommended he stick with “smoking cessation efforts”, the use of nicotine gum.
This final – and apparently successful – bid to stop came amid the stress of plummeting poll ratings and humiliation at the ballot box for his Democratic Party in November’s midterm elections. He was aided by the fact that Marvin Nicholson, his trip director and most regular golf partner, also gave up smoking.
The president and his aides have always been extremely careful to avoid him being photographed with cigarette in hand. The only images of him predate his political career.
Mr Obama’s predecessor George W Bush, a recovering alcoholic, refrained from smoking.
Bill Clinton enjoyed the odd cigar, while Dwight Eisenhower smoked four packs of cigarettes a day.
Smoking rates in the US have dropped dramatically since 1964, when the first surgeon general’s report declared tobacco to be deadly, but progress has stalled in the past decade.
About 15 per cent of the 307 million population smokes to some extent. The government had hoped to push the rate to 12 per cent by last year, but, notwithstanding the president’s efforts, the goal has put off to 2020.
Mrs Obama meanwhile quashed rumours that her husband has been dyeing his hair.
“He’s pretty gray,” she said. “I think that if he had known he would be president, he would have started dyeing his hair years ago. He said now it’s too late.”
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