Your aunt that gained her weight back?
Yeah...I'll bet it's all about her choices.
Thinking of the people I know that have had it done....
One woman, in her 50's, lost an enormous amount of weight, I'm sure over 200 pounds....and 5 years later still has it off. Her job is very demanding and she travel extensively. I've seen her eat before and after, and she truly seems to enjoy her meals more now.
Before, it was like "whatever. I'm fat and I'm tired and really busy, I'll just order whatever" Now, she can't eat as much, and understand she has to make every calorie count, for it's nutritional value. So, she picks only what she absolutely wants, not just eating something because it's there. She looks really really healthy.
Another woman I know lost a lot of weight....and piled it right back on. I sat at a table with her at a work function, where the food was on a buffet, and couldn't believe what was on her plate. pasta salad, some other carb and a bit of vegetables. Too be honest, they weren't little portions either. She was well on the road by that time to stretching her stomach out again. Then, she went back and got a piece of baklava!!!!
Months and months after her surgery, she showed me her scar. It ran up her abdomen for several inches, and looked red and angry and, well, infected. She readily admitted it wasn't healing because she didn't eat enough protein, and her hair was falling out.
The other person is a guy I knew from the gym, and he too kept the weight off. Coincidently, he traveled a lot on his job too.