To dream that you are obese denotes overindulgence. You feel helplessness in expressing your power and authority.
By dreaming that you are obese, you are trying to insulate yourself from your surroundings and protect yourself from involvement in the situation.
Alternatively, the dream may just be a reflection of your waking weight or dieting issues.
You have an skewed perception of your own image which may stem from low self-esteem.