Thin for Life is a great book by Anne Fletcher. In it she gives overviews of about six studies on people who lost weight and kept it off. Then she discusses her study with 160 “masters” at keeping weight off. I think the minimum was 30 pounds for 3 years. But there were people who have lost over 100 pounds and kept it off for decades. And people who didn't start losing weight till they were in their sixties.
It gives her synopsis of their stories through 10 Keys to Success, with each having their own chapter. She also gives a more in-depth profile of one master in each chapter.
I find it to be inspirational reading. It has really encouraged me. I've read it three times this year. Once every three months for the last nine months.
It has some good tips. Not all the stories were those I could relate to, but even if the individual stories don't help, there might be one “key” that will help you.
I highly recommend the book.