Thank you to everyone who took the time to respond. You answered my questions that I was unable find to online. It is getting to the point where he needs to see a vet. He seemed to be doing OK when I started buying dried food with 18% or higher fat. Now he is losing again. He just turned 10. The breeder told me that he was two at first, then five. When she sent me a copy of his papers, it was a surprise when it showed he was eight (and that was two years ago). He looked like a young cat when I got him but he has really aged. I am thinking he is hypothyroid. He has diarrhea, vomits, up most of the night and obsessed with food. His teeth seem fine since he can devour half a chicken breast in a fraction of the time that I can....Yet he is losing weight.