I have a rule' No Diets'! I HAVE been on Weight Watchers since 2002, lost 80 lbs, could've been at my goal weight before this if I really 'worked' it. Most weeks I do it in 'theory', and go to visit with my friends.
In that time I have become healthier than I EVER was at 120lbs.
I eat better, healthier tastier food, whatever I want, plus in reality, I maintained my weight, within 5 lbs, for the last 3 years; I'm not at goal, I still have, as of this week 22 lbs to go, maybe one day I'll get serious and decide I need to be there, but, untill then , I'm pretty happy.
The main thing about losing weight, and keeping it off is you have to eat realistic portions, food that's 'processed ' less, and move more. that's the whole secret. Good luck