Mention "pork in politics," and some people will assume you're talking about legislation that sends barrels of cash back to a politician's district.

But for a growing number of political observers, the word "pork" is taking on a very different meaning that can profoundly influence a candidate's electability: obesity.

For its Nov. 18 issue, Time magazine raised a few eyebrows — and hackles — by running a photograph of New Jersey Gov. Chris Christie next to the headline, "The Elephant in the Room." The recently re-elected governor has famously struggled with his weight, which topped 350 lbs. (159 kilograms) before he had gastric-band surgery in February. [8 Reasons Our Waistlines Are Expanding]

While political pundits debate whether a candidate's girth is an election-day liability, science has weighed in with a somewhat surprising finding: Politicians who are overweight are perceived as more reliable, honest and inspiring — but only if they're male.

The big man wins

In a 2010 study published in the journal Obesity, researchers from the University of Missouri-Kansas City created phony profiles of male and female politicians (with photos) from across the political spectrum. Volunteers were asked to rate the candidates' competence, intelligence, reliability and other factors.

Half of the profiles featured photos of normal-weight candidates, and half featured the same candidates, but with photos that were altered to make the candidates appear obese. The fat male candidate was consistently deemed more likable than his lean counterpart, but the obese female candidate lost out to her thinner version.

"Physical appearance may play a more important role than researchers and candidates have noted," said Elizabeth Miller, co-author of the study, as quoted in The Telegraph. "Potential candidates would be remiss to ignore such stereotypes in contemplating a run for political office."

"On the subject of Chris Christie's weight: If he were a woman, we wouldn't be talking about it," columnist Ruth Marcus wrote in the Washington Post in 2011. But not because the subject is too impolite: "We wouldn't be having this discussion because corpulent Christine Christie, if you can imagine her, probably wouldn't have been elected governor of New Jersey in the first place."

There's an aspect to a chubby male candidate that makes him more approachable, with an "everyman" quality, Marcus noted. "Appearance matters in politics, for male and female candidates," she wrote. "But it is an inescapable fact of political life that for female candidates, appearance matters more."

Stuck in a tub

Other sources have shown that overweight candidates in general tend not to fare as well in elections: Two 2009 polls (one from Public Policy Polling and another from The New York Times) suggested that voters were less likely to support a candidate with a weight problem, according to a Slate column.

There's also a demographic dimension to obesity in politics, leading some to conclude that GOP voters might be a little heavier: In 2008, John McCain won in 16 of the 20 states with the highest obesity rates, while Barack Obama won in 17 of the 20 leanest states, Slate reports.

Obesity, like anything related to public image, has been an issue in politics for centuries: U.S. President William Howard Taft, who tipped the scales at 354 lbs. (161 kg), reportedly once got stuck in a White House bathtub, much to the glee of political cartoonists and other critics. With the help of a British doctor, he lost about 60 lbs. (27 kg) at one point, but struggled to keep the weight off throughout his life.

And the pages of history are stuffed with emperors, popes and kings who ordered their ermine-trimmed robes in plus sizes. But in today's media-saturated electoral environment, looks count for a lot more than in the days when oil-on-canvas portraits were commissioned just once or twice in a public figure's lifetime.

The Centers for Disease Control and Prevention reported in October that 34.9 percent of Americans are obese — a rate that hasn't changed much since 2003. As long as obesity remains a part of the national dialogue, it will continue to be an issue for politicians, too.

Follow Marc Lallanilla on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.

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