While I was reading your post, I was also thinking that it could be dental problems. My Storm had to have a tooth removed last year and he's been eating better ever since. I hope that Taz's weight loss is just due to the fact that he's not eating as much as he normally does. Lots of prayers and positive thoughts are being sent his way. Feline greenies are a good treat to give him to help his teeth. I give each of mine 6 pieces every night. I've also just started putting Liquid Oral Care in their water too.