I have tried many diets and exercises but to no avail

[crossworld]

Please Help!! I desperately need to be fit!!! I have tried many diets and exercises, but to no avail. I manage to lose a few pounds initially whenever I start something new, but I am back to square one again! I am completly exasperated and feel depressed. I do not know what to do. I will go to any extent to get a fit body.