Didn't you say she is denying her possible depression? If she does have depression, she isn't mentally herself and probably why you see her has mentally unattractive. Back when I was with my gf she gained some weight and as did I (her about 30lbs or so she said she did. And me about 25lbs), but didn't really effect me, she was still herself and that's all that mattered to me. Is it possible that because she isn't herself mentally that you don't find her attractive overall? I suppose back then we both could of worked out, but we were both busy and we eventually marked a time on the calendar to start. Never got to that day together though...

As far what to say to her..uh..I guess you could say the truth but not so harshly as you said it here.