To gain weight can be in order to feel protected. Usually we don't mess with BIG animals...
But most of us don't want to be heavily overweight! So how do we loose it?
Well, First by thanking this extra weight, cause once upon a time it filled a purpose. And Second, working both with our conscious and our subconscious mind. Cause our brain doesn't really want change. Which is one reason why a lot of people gain back the weight they have lost. So consciously, with what we eat and how we live. And subconsciously with our self-image.
For inspiration, see for instance neurogym.com.