Not sure if that is going to help, or what a professional nutritionist would say to that, but this is what I do and so far it's been working pretty well, since I have never reached a plateau. The weight was coming off slower at times, sometimes even very slow, but never got stuck at same number.
So I follow my regular low calorie diet (I am trying to keep it low carb and high protein, but that varies) and every two - three weeks for one day I eat very little, day after I eat little over my calories limit and day after I eat very little again. So...
day 1 - 70% of my calorie allowance for a day,
day 2 - over calorie limit by about 30 % (like I wasnt trying to lose but to maintain)
day 3 - 70% of my calorie allowance for a day,
day 4 - back to regular diet
Again, not sure if that's healthy or not, but it keeps my metabolism going.
Good luck and dont give up! I'm with you!