A more literal interpretation of this dream is your fears of gaining weight.
You have an skewed perception of your own image which may stem from low self-esteem.
To dream that others are fat signifies prosperity.
Consider also the phrase it aint over till the fat lady sings and how you need to wait for the final result and not assume the outcome.
To dream that you are fat signifies a fortunate change in your life.
You are experiencing abundance in some area of your life.
Alternatively, the dream means that you are being overindulgent. You need to learn moderation.