I've been on every diet know to man, I've often lost 40-50-even 60 lbs only to gain it all back and more. I was seriously considering that surgical procedure stomach-stapling when I read Fat Wars, maybe it was just right time right place but it really resonated.
For the first time I understood the why of weight gain and lose, he broke it down into his and her fat and gave real life workable strategies and exercise plans. He has a website as well that has excellent articles and advice to keep on track.
I didn't get my stomach stapled and I did loose weight so maybe it will help you as well, good luck!