There is no such thing, it depends on so many variables. What you can stick with, how you prefer to limit what you eat, what your trigger foods are. Everyone does it slighly differently, and for me it's just a case of trial and error to come up with something that works.
The best diet is not a diet - it's a way of life. It's something you can stick to for THE REST OF YOUR LIFE. If you diet, then go back to your old eating habits you will just go back to your old weight (and probably more...).