I had a friend who was pretty hard core on the adkins diet for about a year and a half, he started off by losing 50 pounds in the first 6 months, but after 18 months he has started to put weight back on. He is really happy with the results but he still has weight to lose, but his diet isn't working any more.
Call me old fashioned but I am sticking with the tried and true well balanced diet with regular exercise. I don't have anything against a specific diet like adkins, but I am only 30 years old and have no serious health risks so I am in no hurry to lose these 40 pounds.