My 4 yr old female cat was spayed a few months ago and subsequently gained much weight very rapidly. We have noticed her ravenous appetite as well. Its hard to regulate her food, as we have another cat as well, and she tends to dip into his food as well. She is MUCH heavier and LOOKS pregnant. Anyone familiar with this? I don't think she has parasites, since her stools seem to be OK. Could this be some kind of hormone imbalance triggered by the spaying?