This cat is certainly overweight - and while some people think fat cats are cute (I plead guilty), there is such a thing as TOO fat. This cat can barely walk. Bear in mind that cats that are overweight are more inclined towards diseases like high blood pressure, diabetes and heart problems and make sure to put your cat on a diet if it needs one. How do you know if your cat is overweight? Check out this link.
Also please remember - keep your cats in. They could get lost easily otherwise.