Originally Posted by stephenq
Cats like people tend to gain weight as they age, not lose it. Losing weight can be a sign of an illness, often caught early if you don't wait for more symptoms. .
Depends on how old you're talking...really old people...85+ generally start losing weight because their metabolism functions start to fail, and often, they lose interest in eating..but not due to illness per se...just due to lack of interest, taste changes, smell changes...simply...the changes due to the aging process. Their bodies can't metabolize the foods that they do eat, so it passes through without capturing the calories and nutrients.
This doesn't apply to every old person of course...or every old cat...but alot of really old cats that I've seen..over 18 yrs who used to be normal to plump are quite slim/thin..and yet, eat a normal serving. They seem to manage fine without the weight.
Loss of weight in an young to old cat...2-15 yrs...sure can be a sign of illness and is best investigated quickly.