It’s fairly easy for your cat to seemingly become obese overnight. Because you see your cat every day, you may not notice he is gradually gaining more and more weight. You may notice, however, that he is less inclined to play and spends more time sleeping. This lethargic attitude is a symptom of obesity and should cause you to examine your kitty more closely. You will likely find that he’s a few pounds heavier than the last time you checked.