Hi I have a cat, Shadow, that is 1 1/2, he is a domestic longhaired cat that i have had since a kitten. Lately i have noticed that he is getting very skinny, i thought he was eating fine but when i tried to feed him today he ate a whiskers satchet and only sniffed the dry food but did not eat any. i think my kitten has been eating the food for the both of them as she is getting fat. Shadow is not a very playful cat or very active inside so hard to tell if he is sick or not as he has always been very aloof and not interested in toys. Please can someone help with ideas as to why he is loosing weight?