"Buckle up, Governor Christie," comedian Joel McHale said as he opened his set at Saturday's White House Correspondents Dinner. "Excuse me — extender buckle up."

Get it? Because Chris Christie is fat.

McHale kept returning to Christie's girth. "Speaking of digestive systems," he said later, "Chris Christie is here. He's actually here tonight. Wow, sir, you are a glutton — for punishment."

Ho ho ho.

Christie has a reputation as a bit of a bully. But anyone watching the White House Correspondents Dinner this weekend saw Christie getting bullied. And in a perfect echo of the rhythm of high-school humiliations, he even had to pretend to enjoy it. "I thought he was great, and that's exactly what I expected," Christie told Vanity Fair later that night. It's a lesson every heavy kid learns in homeroom: the only thing people hate more than a fat person is a humorless fat person. You better at least pretend to be in on the joke.

Anyone watching the White House Correspondents Dinner this weekend saw Christie getting bullied

The White House Correspondents Dinner celebrates the freedom Americans have to speak truth to power. And McHale's set, which was otherwise great, had plenty of that — including a cutting riff on Christie's scandals. But when a trim, handsome guy like Joel McHale repeatedly mocks a fat man for being fat on national television, it's not speaking truth to power. It's bullying. It's a reminder to any overweight kid who happens to be tuning in that even if you become as successful as Chris Christie you'll still be mercilessly mocked for your weight.

It's not just McHale, of course. Remember this Time magazine cover?

This is more than a question of making people feel bad about themselves (though that, honestly, should be enough). Size discrimination is a powerful force in American life. A few examples:

Researchers at Bowling Green University found that "individuals with a high BMI were less likely to be offered admission to a graduate program when the application involved an in-person interview."

Researchers at the Yale Rudd Center for Food Policy & Obesity found that male jurors were much likelier to judge obese women as guilty of crimes. The study's author, Natasha Schvey, said that the "prevalence of weight-based stigmatization is now on par with rates of racial discrimination, and has been documented across multiple domains, including employment, medical, and interpersonal settings."

study in the International Journal of Obesity gave people resumes with pictures attached. In some cases, the picture was the person before weight-loss surgery. In others, the picture was of the person after weight-loss surgery. Resumes with pictures of obese women were rated as showing lower leadership potential and deserving a smaller starting salary. The prejudice was greatest among evaluators who believed themselves particularly attractive.

A heartbreaking study in the journal Obesity suggested that size affects how parents feel about their children. "The researchers looked at 379 college students and discovered that those who paid for their cars themselves had a higher average body mass index in relation to students whose parents helped with the purchase," Time reports. Neither gender nor family income explained the discrepancy.

suggested that size affects how parents feel about their children. "The researchers looked at 379 college students and discovered that those who paid for their cars themselves had a higher average body mass index in relation to students whose parents helped with the purchase," Time reports. Neither gender nor family income explained the discrepancy. Speaking of children, a study in the journal Pediatrics followed 800 kids between grade three and five across 10 cities. Parents and teachers were interviewed about the children's social skills, so researchers could develop a baseline understanding of how socially adept the children were. They found that holding social skills constant, obese children were 65 percent more likely to be bullied. And it's worth noting that holding social skills constant might be a mistake: heavy children who are bullied at school might have more trouble becoming social butterflies.

There are many more studies reporting similar results. Size discrimination is a very real thing: it makes people miserable, it costs them jobs, it costs them money, and it can even land them in jail. And it's reinforced as normal every time people make fun of Christie's weight. After all, if even a guy as successful as Christie deserves to be mocked for his girth, then every other obese person in America is obviously fair game.

One of the odd things about McHale's jokes is Christie is looking a lot slimmer these days. You can see it in this picture he took with McHale afterwards to prove he's a good sport.

Christie's weight loss isn't a mystery. About a year ago, he had lap-band surgery to help him lose weight. WebMD describes the procedure:

Adjustable gastric banding is done through several small cuts, called incisions, in the belly. The doctor will place small surgical tools and a camera through the incisions. The doctor will then wrap a device around the upper part of your stomach to form a ring. Attached to the ring is a thin tube leading to an access port that is left under the skin. The access port is the place where the doctor puts in a needle to add or take away saline. Adding saline tightens the band and makes the stomach smaller.

Which is to say, Christie loathed his size enough to pay doctors to cut into his stomach and make it harder for him to overeat. That might well have been the right decision for Christie's health. But it suggests that he's suffered enough with his weight that getting mocked for it on national television is a bit gratuitous.

So go after Christie for his scandals, or his bullying, or his awful budget predictions. But stop making fun of his weight. As Melissa McEwan, who's been on the Christie fat-shaming beat for awhile, tweets: