My brother, an M.D., used the Adkins diet years ago to win a weight-loss bet with his wife. After he won (the diet worked) he blimped out again within a couple of years. the only diet that works long term is the "Hungry All The Time And Get Used To It" diet. Unless someone comes up with a magic pill without the side effects of speed.
This is a good diet for people without risk factors for heart disease, high cholesterol, bowel cancer, etc, or for people who eat low-cal proteins like chicken and fish. You have to factor that in. For example, being a vegetarian, I tried Atkins and was eating all high-fat foods, like avocadoes, nuts, olives, tofu and cheese. My dad died of colon cancer and I am borderline in the cholesterol department. Although avocados, olives and nuts are high in the good cholesterol, overall, this was still a bad diet for me. And I also gained weight, as I could not be full without eating more than the prescribed amounts, i.e. 1/4 cup of nuts.
All this is to say that weight is not the only consideration -- your family history is very important.