Sticking to that diet obviously works. Not sticking to it obviously doesn't.
I don't mean to be snide; my mother is practically on Atkins and has nearly eliminated insulin, and if anything can't gain enough weight. Salads, meats and cheese - go nuts, and the weight will drop. It's the carbs that do you in.
I was a big proponent of the Atkins diet...and still am. However, last year I was diagnosed with kidney Cancer and have had a Radical Left Nephrectomy and am now left with one kidney that is not entirely healthy. I'm afraid to eat all that protein again.