I don't blame Kat for his addictions, but she definitely isn't doing anything to help. Panda actually tried to make food that was somewhat healthy and didn't involve tons of red meat because of his gout. Phil was actually losing weight for a time and then the hospital saga hit. Kat doesn't seem to care as much about Phil as Panda did. It definitely could have just been a young dumb love with an extended honeymoon phase, but Panda actually did try to make Phil a better person even if only physically.