When Mad Men viewers got their first glimpse of polarizing housewife Betty Francis this season, January Jones' character was struggling to zip herself into a party dress and failing, despite the help of both her kids. The harsh truth: Betty's gotten fat. The surprising sight of Jones — pregnant in real life at the time of filming — outfitted in a body suit and prosthetic makeup quickly divided fans, and a bonafide backlash has erupted. (One fan has even set up a Twitter feed, @FatBettyFrancis, to mock the whole ordeal.) Here, a guide to the "Fat Betty" controversy:

What exactly happened in this episode?
The new, bigger Betty spent a lot of time slumped on the sofa, scarfing down Bugles, until her officious mother-in-law commanded her to take diet pills. But the doctor to whom Betty appeals for the pills finds a lump on her neck that could be thyroid cancer — which can cause weight gain. Though Betty panics, the tumor ultimately proves benign. "It's nice to be put though the wringer and find out I'm just fat," she pouts. The episode ends with Betty gorging on ice-cream sundaes. 

What did critics think?
Some felt that Betty's cancer scare and weight-related insecurities made the typically chilly character instantly more relatable. "I don't think I've ever seen the complicated emotions that come with a woman's unwanted weight gain handled so elegantly on television before," says Tracie Egan Morrissey at Jezebel. The arc is particularly poignant considering Betty's character history, says Aly Semigran at Hollywood. She's a former model whom we've seen smoke her way abstemiously through family dinners, and who's criticized her young daughter's weight. This was Betty as we've never seen her: "Not just Fat Betty. But, Vulnerable Betty and Downright Human Betty."  

How did other critics react?
With anger. "I felt sorry for both the actress and the character," says Matt Zoller Seitz at New York. With this regrettable plot, Mad Men "is walking a thin line between showing us an unlikable woman victimized by a sexist society and dramaturgically beating the crap out of her." Actually, that line's been crossed, says Meredith Blake at the Los Angeles Times. The weight-gain plot seems unnecessarily cruel, and there's "something fairly sadistic about her cartoonish make-up." Was adding "some extra chins and a spare tire" really the only way to make Betty seem relatable, says Pedestrian. It just seems lazy.

Is January Jones really that fat?
No. While the actress, who was pregnant with her new son at the time, had put on weight, she wore a fatsuit and prosthetic facial and neck appliances to make her appear fatter than she was. Critics were unimpressed by the execution: My first thought was, "Good lord, is she wearing the same sort of prosthetic they used on Eddie Murphy in Norbit?" says Jen Chaney at The Washington Post. The show used a body double for a scene in which Betty is seen naked emerging from a bathtub.

How is the backlash unfolding?
On Twitter, some fans were childishly revolted: "After seeing what fat Betty Draper looks like, I kind of want to starve myself…" one fan said. "Betty (Draper) Francis really needs to die. Can't stand her and now that she is fat, she serves no purpose," tweeted another. Bloggers have been dissecting the significance of the reaction to the weight gain, with posts like "Fat Betty debuts on Mad Men and what it means," and "Mad Men and the Fat Betty conundrum." A fake Twitter account called @FatBettyFrancis debuted. Its "Betty" tweets things like, "Good morning, does anyone know if Doritos makes a breakfast cereal?" and "The only good thing about Sally getting home from school is that I can smell the cafeteria on her clothes." 

Sources: E! Online, Hollywood, Hollywood Reporter, Huff. PostJezebel, LA TimesNew York (2), Pedestrian, Tauntr, TwitterWash. Post