If you want to be and stay lean, forget the "quick" fix. You will need to change the way that you eat and the way you see food in general. You need to focus more on the nutrition for your body, less on the gluttonous aspects.
It's hard at first but it becomes easier as you get trim and feel better.
Check out this thread for diet basics:
For the record, when I recommended the short term low carb thing, it is not for the sake of losing quick weight, necessarily. If you remove most carbs from your diet, then the majority of the immediate weight lost will be water (carbs hold more water in the body). So yes, if you go back to eating "normally" then you will gain that water weight back, but it wasnt FAT loss to begin with. The theory behind it is to get yourself out of the habit of eating high carb junky foods. Your blood sugar will even out and cravings will dissipate. I find that it makes sticking to a healthier diet in the long term a bit easier.