doudou -
you've gotten some really good responses here & some fine support. Please allow me to add that when you say you want to "lose weight fast" you're basically sabotaging yourself then & there.
No matter if you use Atkins, Weight Watchers, SouthBeach, whatever - when you "lose weight fast" you are basically losing only water weight, and you'll eventually ditch your diet & go back to your old eating habits; therefore putting all that weight back on again... & usually MORE weight on top of that.
The really TRUE WAY to lose weight & keep it off can be any number of diets... but the simple fact of the matter is that you have to DO IT FOR LIFE. You cannot do it for a little while, lose the weight, & then expect to keep it off. Whatever you use to lose weight,
you must commit to it forever.
Nobody ever likes to hear that. Me, included! - but it's the total truth.
Good luck! - I think you can do this! - you just have to
find the right way for you. 