Back in the meeting room, all four Cottages are present when House wonders how a sick person could suddenly get better. "It's called an immune system," Hadley says. Is your immune system curing your Huntington's, Hadley? No! So shut up. House clarifies that sick people who are sick enough to be his patients don't suddenly get better. That's usually because he makes them worse, though. Taub says he gave Emmy an MRI, they had chocolate cake, and then she went to bed. The cake is significant to House, who then snaps at Taub for not telling him about it earlier.
Taub and House enter Emmy's room with a full chocolate cake. House says he's got her cure. She assumes he's joking, because it's a cake. That doesn't even cure the blues, really. I mean, at first you think it does, but then you just feel fat and even sadder than before. "Hereditary coproporphyria," House says, offering her a bite. She turns away, so House has to trouble himself with explaining the situation. Hereditary coproporphyria is a condition where your body doesn't make enough of the enzyme coproporphyrinogen oxidase (House didn't want to bother pronouncing it, but I have looked it up for you!), thereby causing all of Emmy's symptoms. The treatment is a high-carb, high-sugar diet, so when Emmy was eating badly and gaining weight, she was actually treating her disease without knowing it. Now that she's eating right, the symptoms have shown up. They sure took their sweet time to do it! Emmy must have had that surgery years ago to be that thin, have skin that perfect and tight, and have built up a big career as a fitness instructor now. Taub says they'll reverse the bypass and Emmy will eat her former favorite foods again. She'll gain the weight back, but be healthy. House offers her another bite of cake. She rejects it again, and says she'd rather be on a drug that will "manage" her symptoms than be fat and cured. "Not many people have the guts to admit they'd rather be pretty than healthy," House says. Would she be healthy, though? She won't have the HC, but she'll have all the other stuff that comes with being overweight and eating unhealthy foods. Emmy's pretty much in a lose-lose situation. Might as well pick the option that gives you the most self-esteem.