2nd this. your mirror will make u feel a little more confident if you get in better shape (this only makes a difference to the superficial, though). however, when you exercise, your body releases endorphins which do things like a) heal injuries b)soothe pain c)give you energy or to sum it up- endorphins make you feel good. plus, if you are working out for 2 hours, you aren't sitting around thinking about whatever it is that has you depressed in the first place! even if its only for 2 hours, its better to be depressed for 22 hours a day than 24 right?
its not a certain answer. shit look at the milli vanilli guy. he was fuckin SHREDDED and GORGEOUS and he still killed himself due to an unbeatable depression. Dennis Rodman is in fantastic physical shape and he is the most depressed guy I've ever met. Nice guy though, just fyi.
anyway, you're big enough for her. and if you're not, then maybe she's just too fat. tell that fatty to lose some weight because even a 747 looks small when you fly it into the grand canyon. then sigh next time she orders anything other than a house salad when you go out to eat. sigh, make it obvious, then immediately change the subject to something about sports. talk about Rodman.