You don't realize how fat you are when you've passed that line between chubby and obese. That is the danger of gaining weight gradually over the years - you put on so much until one day you are dumbfounded as to what you used to be and how you are now.
I know that is a fact. I have a friend that thinks she is just right for her weight but I keep seeing her gaining weight. I'm too afraid to tell her anything in case she becomes depressed.