I just had kittens back in the summer time and by the time the kittens were old enough to be found homes our cat Alex was drained really thin now im no vet but it does take alot out of them ecspecially when they have large litters now i still have the two males left and mom cat dont want anything to do with them and our other cat callie actually produced milk and is still feeding them and there almost a year old...every cat that i have owned with kittens has always gotten thin through out the 2 months they care for there young