Three people that I know have had stomach surgery for weight loss. Two of them lost a massive amount of weight in a short period of time but after about a year they started to gain it all back. They started to eat more and more until they stretched the stomach pouch back out again.
One woman that I worked with had a lot of success, lost about 100 pounds, but now she looks like skin and bones. She suffers from frequent upset stomachs and is sick all the time.