I have a similar problem too. I have an 18 year old cat who needs to eat several times a day and I have a 4 your old female who is a food addict (she would eat practically anything, cat food, human food, it does not make a difference - the only thing she is not keen on is fish). I think that sometimes it's just boredom, she is also a bit lazy. Her favourite game is when I throw one of those dried pellet things and she just runs very fast to get there first and eat it (my third cat likes this game too and it's quite funny seeing them race to see who gets there first). This way thought she eats less of them and well, at least I make her run a bit!