It's an unwashed body smell. Hard to pin point exactly what and I'd rather not think about it.

We don't have desks, I work in a pharmacy. Thing is she always stand really close to people when she's talking to them and doesn't understand the concept of personal space. Even if you take a step back she steps forward. So there is no escape.

There's another person at work who stinks of alcohol but that's been excused as her medication (no one believes it as she's admitted to drinking a bottle of wine a night before).
Fat does not make you fat. It's actually pretty important.