Can You Really Lose Weight Fast?

Is there really a way to lose weight fast, without gaining it all back again? Like many, I have tried many diets, and exercise routines, and anytime that I try to lose weight fast, it seems to come right back - sometimes with even a few more added pounds. When you lose weight fast, is it not always fluid? And, does losing weight fast not cause your body to go into starvation mode, for your metabolism to slow down, and actually cause your body to want to gain weight? Everyone wants the fast, and easy way out - for myself, and many, we want to lose those extra pounds fast, that we despise so much. So can you really lose weight fast?