My weight has been up and down for years and only once (Thanks to Weight Watchers) have I been a reasonable weight.  I lost 40 pounds and kept it off for 3 years!  Although I am very proud of that accomplishment; I , of course, see it as failure that I didn't keep it off.  many factors contribute, mainly my sedentary life.  I now have a job that keeps me very active and I know once I lose the weight this time, it will stay off for good.