In the country of the fat, the President must be thin, it seems. In the US, where two thirds of the population is overweight and more than a quarter is obese, a candidate for the highest office is under attack because his stomach sticks out over his capacious trousers.
Chris Christie, the straight-talking Governor of New Jersey, won himself a second term in office earlier this month by a crushing majority, in a state where Democrats outnumber Republicans by 700,000. His achievement in attracting a majority of the votes of women, despite his opposition to abortion rights, and Hispanics, and in making inroads into the youth and the black vote makes him the strongest contender for the Republican nomination in 2016.
However, though his opinions are, by UK standards, way to the right of centre, they are not right-wing enough for the GOP's strident Tea Party wing, some of whom evidently think they can block his candidature by raising doubts in the public mind about whether a fat man is fit to be President.
They do not use direct attacks to make his weight an issue, because that would carry obvious political risks in a country where obesity is sufficiently serious for the polling company Gallup to produce monthly reports on its progress. The current month's figures confirm that 2013 will be the worst year for obesity since monthly records began in 2008, with 27.2 per cent of the population classed as obese, 35.5 per cent overweight, and barely a third the right size. Instead, Christie's enemies drop hints that draw attention to his ample stomach without actually mentioning it.
In the summer, Christie made a barbed comment about his rival from Kentucky, Senator Rand Paul, from the party's Tea Party wing, suggesting that the generous federal aid that goes into Kentucky owed something to "pork barrel politics".
"This is the king of bacon talking about bacon," Senator Paul shot back. Last week, Senator Paul did it again. Asked whether he would appear on a radio show with his rival, he replied that he would, adding: "If there's a State Fair, we could go for a fried Twinkie."
A Twinkie is a yellow, sponge-like, cream-filled cake so loved by binge-eaters that in law there is what is known as the "Twinkie defence", after a lawyer attempted to get his client off a murder charge by arguing that an excess of junk food had impaired his mental capacity.
Senator Paul is not the first to metaphorically prod Christie's belly. When Christie stood for the New Jersey governorship in 2009, the Democrat incumbent, Jon Corzine, ran a television advertisement showing him walking in extreme slow motion, with flesh moving in several directions at once. In case anyone missed the point, a narrator remarked that Christie "threw his weight around". This year, as Christie ran for re-election, his Democrat challenger Barbara Buono remarked in a speech that surfaced on YouTube: "Seeing Chris Christie frolicking on the beach is not going to drive me to go to the shore."
It has also been alleged that Mitt Romney rejected having Christie as a running mate in 2012 solely because of his weight. Watching a video of Christie without a suit jacket, he is reported to have exclaimed: "Guys! Look at that!" John Kasich, Governor of Ohio and another possible Republican contender in 2016, described Christie, rather more respectfully, as a "big teddy bear".
Journalists, too, have joined the game. Time magazine ran a cover with Christie pictured in silhouette behind the headline "The Elephant in the Room". Eugene Robinson, a commentator for the Washington Post, argued that in a country suffering an "epidemic" of obesity, it is legitimate to attack Christie for being overweight, adding: "I'd just like to offer him a bit of unsolicited, nonpartisan, sincere advice: eat a salad and take a walk." An opinion piece by a Bloomberg columnist, Michael Kinsley, came straight to the point in its opening sentence: "Look, I'm sorry, but New Jersey Governor Chris Christie cannot be President: he is just too fat."
In past elections, Christie his risen above these taunts with panache, even turning them to his advantage, just as men in the middle ranks of national politics in the UK made light of their weight - if you will pardon the expression. The fattest man seen in the Commons since the war was the former Liberal MP, Cyril Smith. His posthumous reputation is in tatters because of details that emerged about him sexually abusing children, but while he was a practising politician, his immense size made him one of the most easily recognised political figures, and aided his chances of being re-elected.
Similarly, the Environment Secretary, Eric Pickles, has never suffered politically because of his larger than average girth, though he finds the jokes that others make about it very tiresome. He exacted revenge on George Osborne for one such joke, by posting a picture of himself on Twitter eating a modest salad after the Chancellor had been pictured devouring a burger from upmarket purveyor Byron.
But a British Cabinet minister, or a US state governor, does not have to endure the intense personal scrutiny of a presidential election, when voters will be invited to ask whether the candidate is physically fit enough to be the Commander in Chief, the person with a finger on the nuclear button.
Christie's progress will doubtless be watched with interest by the Australian ambassador in Washington, Kim Beazley. He aspired to the top job in Australia's government as leader of the Labor Party, but with an election looming, his colleagues sacked him in December 2006 and installed Kevin Rudd in his place. One reason that they judged him to be an electoral liability was his weight. In 2005, John Howard, the Liberal Prime Minister, pioneered the tactic now being deployed against Christie, by drawing attention to Beazley's girth without mentioning it directly, taunting Beazley with the phrase: "He does not have the ticker." The following year, a Liberal MP, Wilson Tuckey, was not so subtle: during an angry exchange outside Parliament, just before Beazley was ousted, Tuckey shouted at him: "You big fat so and so!"
We do not know how the British electorate would react to being asked to put a fat man or fat woman in Downing Street, because none of the main parties has fielded an overweight leader in the television era. However, when Edward Heath lost office in February 1974, he was secretly suffering from a thyroid condition that caused him to balloon while he was Leader of the Opposition. One Tory MP, Airey Neave, who saw him privately, thought that he was not fit to continue as party leader, looking so fat and red-faced. Heath did not resign, so Neave took on the job of managing Margaret Thatcher's leadership campaign.
The lesson was not lost on Baroness Thatcher, who was obsessively anxious about her own weight, surmising - probably correctly - that it would be a major problem for someone aspiring to be the UK's first woman Prime Minister to look as if her weight was out of control. Amid the stress of the 1979 general election campaign, she had a self-imposed daily diet sheet designed to make her lose 20lbs, which included a total ban on eating between meals.
The only other woman to look like a serious contender for the Tory leadership is Home Secretary Theresa May, who has encountered the opposite problem. In February, the chairman of the Commons Home Affairs committee, Keith Vaz, noted that she was looking thin and wondered if the stress of the job was getting to her. To stall any more such speculation, she revealed that her two stone weight loss was brought on by diabetes.
The case made against fat leaders has been well made in American newspapers, where it has been written that a candidate looking like Chris Christie is a bad example to children, that a fat person's health is likely to give way under the stress of high office, and that someone who lacks the willpower to lose weight has not the mental strength to lead the country. There is perhaps another unspoken reason: it is fun to be prejudiced, and fat people who take up more room and consume more food than the rest of us are a group we feel we can insult without thinking badly of ourselves.
However, there is no universal rule that fat people cannot succeed in politics. Anyone who thinks there is, need only cast their eye over Israel's successful politicians, such as Ariel Sharon, whose very ample girth did not prevent him being elected Prime Minister twice, and may even have helped. But Israel has to fight for its very right to exist. To quote Sharon's former media adviser, Arnon Perlman: "Sharon's heaviness conveyed to the public a sense of stability at a time of great inner turmoil."
In a wealthy, stable society such as ours, or that of the US, where anyone can get fat but people struggle to stay slim, we prefer our leaders to look lean and fit rather than reassuringly enormous. It was rude of that commentator to tell Christie to eat salad and take a walk: but, realistically, it was not bad advice.