I have a 7 year old female Maine Coon that has recently lost an alarming 3lbs. I can now feel her bones sticking out through her coat. In addition, she has developed a voracious appetite where she's eating upwards of 5 large cans of food each day, about 25 ozs. I've been able to stabilize her weight by feeding her as much and as frequently as she wants. She's been on the same wet food her whole life. She has terrible diarrhea, which includes undigested food. Her coat doesn't look good and she's losing hair. My once super energetic interactive cat has become lethargic and depressed. Cali is spayed and is indoor only. Her lab results were completely normal, except for mild dehydration. The vet said Cali could have a multitude of problems, including cancer or thoracic tumor or IBS. She recommended an abdominal ultrasound, but the vet that performs that test only comes to their clinic once monthly and she's not due back for another 3 weeks. Since hyperthyroidism, kidney disease and diabetes have been ruled out, does anyone have any thoughts about what could be wrong with my beloved companion?