Chris Christie, the Republican heavyweight, is really heavy

TAMPA, Fla. — New Jersey Gov. Chris Christie may quickly win over many in the national television audience with his gruff, everyman persona and sharp critiques of a staggering economy when he delivers the keynote speech at the Republican National Convention on Tuesday night.

But it is Christie’s other profile — his substantial physical one — that undoubtedly will make the first major impression on millions of television viewers.

Christie is bigger than any other major national political figure in recent memory. He is heavier than any president — an office many Republicans dearly hope he will one day hold — in 100 years. Though he hasn’t disclosed his exact weight, it seems apparent that only William Howard Taft (the Republican president from 1909 to 1913) can come close to matching his girth.

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Does it matter? It didn’t hurt Christie, who will turn 50 on Sept. 6, as he pushed past Democrat Jon Corzine in 2009 to become governor in a heavily Democratic state that is the 11th most populous in America. He has overhauled teacher tenure and helped rein in state employee pensions, but has not been able to do much to alleviate persistent unemployment.

Those getting their first impression of Christie will be comparing him to a battalion of toned and tanned politicians. The ascendance of one with (in Christie’s own words) a “big, fat rear end” may come as a relief. This leader must have his eye on something more important than his scale and his Q score.

Christie does not shrink from his substantial mass. He once joked to Don Imus that he weighed 550. Introduced to the Michigan delegation at the convention Tuesday morning by a woman from a restaurant trade group, Christie could not resist. “Did she just ask if I’m aware of the restaurant industry? Seriously?” Christie deadpanned. “Yes, I am mildly aware of the restaurant industry, in New Jersey, New York, Pennsylvania, Delaware, Connecticut. Yeah, the entire region!”

The Michiganders roared.

Christie supporters conceded that in recent months the already sizable governor has layered even more bulk on his 5-foot-11-inch frame. His weighty challenge turned serious in July 2011 when the governor had to visit the emergency room for chronic asthma, a condition he conceded had been exacerbated by his weight.

He acknowledged to Oprah Winfrey , “I don’t like being overweight.”

Others have been less sensitive. When Christie shouted down a profanity-spewing heckler this year, David Letterman put the confrontation to music. The late-night comedian said inciting Christie amounted to “crossing a rhino.”

But fat jokes may not have political traction. Corzine aired an ad that used super-slow-motion video of Christie stepping from a car as a voice-over taunted that he “threw his weight around” to avoid traffic tickets. The Democrat lost by 4 percentage points.

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With mountain-biking George W. Bush and basketball-playing Barack Obama the most recent models, the presidency has become the home of determined mesomorphs. Mitt Romney works out daily on an elliptical machine and vice presidential candidate Paul D. Ryan has led exhausting P90X fitness regimes for fellow members of the House of Representatives.

Speaking on ABC’s “Good Morning America” about his aspirations for the keynote speech, Christie set a relatively modest goal. “I think if the American people watch tonight, leave the speech by saying, ‘Yep, that’s him, that’s who I heard about, seems genuine to me,’ then I think I will have done my job for me,” he said.

The governor will be putting considerable weight behind those words. And every pound will be proof to his backers that he, indeed, is the genuine article.

Follow Politics Now on Twitter and Facebookjames.rainey@latimes.com

Twitter: @latimesrainey

Michael Memoli contributed to this report.