My cat, Rat-T, is really fat. She weighs a lot. She even has the nickname "Fat-t, Rat-t". Most people are amazed at her size. She's been heavy for a while, but she has always been so playful and energetic that it hasn't been much of a worry - cause it's always been a muscular sort of fat. She's always been very healthy - still is. But the older she gets the less she is being active. And I'm already starting to see some of this "fit fat" become "flob" in a couple places. And that worries me. She really loves her food. She always knows when we are eating - no matter how quiet we are. She even knows if we are opening a pouch for another cat - now those things make absolutely no sound at all. I mean, she even knows if she is outside or at the other end of the house in a completely different room. I actually call her the "food psychic". Does anyone have any advice for me? Should I be concerned? What weight is a healthy weight?