I don't disagree. I'm very much in the low-fat (but certainly not in the no-fat) school of thought, and I strive to make what fat I do consume to be mostly mono-unsaturated, such as olive oil. And certainly I don't think that an occasional steak will kill you. And of course too much of anything can be bad for you. But I contend that Atkins advocates (or permits) grossly too much fat, and too much protein as well.
One thing's for certain: the argument won't be solved here. But I'll continue my omniverous ways, with an emphasis on vegetables and whole grains; that plan has served me well.
Increased muscle mass?
Fat loss?