We have all seen stray cats who looked pitiful with their ribs protruding, and our instinct is to bring them home and fatten them up. In a cat of normal health and weight, the ribs would not be visible to the eye, but you could definitely feel them if you rub the cat’s torso or pick up the cat.
The sign that the cat is obese is when you use the touch test and can barely feel the ribs underneath. You’ve got a fat cat on your hands, and while the cat (unlike its human owner) doesn’t care how she looks, too much body fat can lead to health problems.