Chris Christie got laughs on the Letterman show last week when he showed up with a doughnut. I get what he was trying to do. People keep goofing on his girth, and a former White House doctor had just told CNN that if Christie were elected president, "I'm worried about this man dying in office." So he figures that the best way to defuse the issue is to make light of his weight.

But this is no laughing matter.

Connie Mariano, a physician who served eight years in the White House medical unit (and for what it’s worth, she’s also a Republican), said of Christie, "I'm worried he may have a heart attack. I'm worried he may have a stroke." She's right to worry, statistically speaking. The Centers for Disease Control and Prevention, plus any medical expert with a pulse, will state the obvious: Obesity ratchets up the risk of coronary heart disease, Type 2 diabetes, at least three kinds of cancer, hypertension, liver disease, gall bladder disease, sleep apnea and related respiratory problems, and osteoarthritis.

Various combinations of those ills can be life-threatening, as evidenced by the fact that the annual medical care cost of obesity in this country is roughly $150 billion. Christie did some extensive damage control last week, alternating yuk yuks with braggadocio ("I’m the healthiest fat guy you’ll ever meet,” he told Letterman) and rhetorical bile (declaring in a press conference that Dr. Mariano should "shut up"), but the fact remains that if he does get serious about 2016, he’d need to be extra transparent about his medical records. A hefty percentage of voters would demand no less.

There's no transparency requirement; it's merely a contemporary custom. Presidential candidates in recent decades have occasionally come clean, while others have played hide and seek. Early in 2008, John McCain released 1173 pages of his medical records; Barack Obama released only an undated letter from his doctor.

But probably the most egregious omission occurred back in 1992, when Democratic candidate Paul Tsongas, a cancer survivor, publicly insisted - as did his doctors - that he was cancer-free. Only later did we learn that he was not. He died of the disease on January 18, 1997, after repeated hospitalizations. Which means that, had Tsongas been elected in ’92, he would not have completed his first term. (After Tsongas belatedly 'fessed up, he urged President Clinton to create a national commission that would determine what medical information candidates should disclose. Clinton punted that one.)

It’s easy to riff on Chris Christie’s weight and to recall the fat presidents of yesteryear - such as orotund William Howard Taft, who wanted to ride a horse during the 1908 campaign until his chief adviser, retiring President Teddy Roosevelt, insisted that such a stunt would be "dangerous to him and cruelty to the horse." It’s easy to Google the Christie fat jokes and gorge on them. It’s harder to talk with appropriate sensitivity and severity, about politicians and their medical issues.

History requires that we be vigilant. Woodrow Wilson had a stroke in office; he was so incapacitated that, his wife secretly ran the country at a time when the administration was trying to win Senate approval for America’s membership in the League of Nations (Wilson’s effort failed). A quarter century later, Franklin D. Roosevelt ran for a fourth term even though (as we now know) he had already been diagnosed as deathly ill, and historians will forever debate whether he was fully engaged with Stalin at Yalta. In 1960, the Kennedy campaign covered up JFK’s chronic battle with Addison's disease, and historians will forever debate whether his constant pain and constant injections hampered his performance as president.

And when you consider the heightened attention paid in recent years to the obesity stats – not just in adults, but in children – it’s clear that, as a '16 candidate, Christie wouldn’t be able to mollify the public with a mix of jokes, bluster, and bland reassurances that he’s working with a trainer. He’s currently tagged as a "front runner" in the Republican race - granted, it's a lazy label, given our current distance from '16 and the paucity of Republican alternatives - but he won't run far unless he walks us through his medical records, so that voters can make up their own minds.

Lawrence Altman, a physician who covers medical issues for The New York Times, noted in an '08 interview that candidates are "very reluctant to actually turn over information and invite an independent check." But these days, he said, the public "wants to know more about the health of the people who were going to run their country." He got that right.

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Best line from last night's episode of Downton Abbey - courtesy of Mr. Carson, who oversees the servants. While seeking to fire an employe for homosexuality, he declared: "I've never been called a liberal in my life, and I'm not going to start now!"

And when Mr. Carson rebuked the servant ("I do not wish to take a tour of your revolting world")...well...it was Britain circa 1920 meets the Republican base circa 2013.

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This week, we get the four sweetest words in the English language. And, no, it's not "State of the Union."

It's "Pitchers and catchers report."

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