JD Jones has it right....many lose tons of weight..."no pun intended he he"...over time they do gain it back without the proper education and follow up to the surgery, the surgery alone is not the answer, the stomach will stretch back, the band sometimes slips, it need adjustment frequently. There is a need for counciling, Nutritionist and dietician monitoring as well. Gastric bypass surgery is the permanant answer, however I have heard some gain back this weight as well.
They wouldn't call it a "Losing Battle" if it were not true....Good Luck to your wife's friend....