I'm trying to find a common or easily transmitted illness that would prevent a person from eating for several days (or keeping down/digesting food). I know there are a lot of things that can make eating difficult or unpleasant, but I need something with a better success rate. It would also need to be treatable.
Essentially, I have a plot point that revolves around killing off a portion of the population who are 'infected' for lack of a better explanation. The infected have almost zero percent body-fat, which means they would starve quickly, while 'normal' people would just be very hungry (and sick).
Sadly, I'm not a pathologist, and I'm not sure how I would format this question to search Google.