I'd also be interested in this adaptation theory. As far as I know, the body only responds with lowering metabolic rate when daily caloric intake drops below that which is needed to sustain BMR on a consistant basis, which the author above seems to have done if he was truly only taking in 1,350 calories per day and is a 6' 1" male. If I remember correctly, Dr. Atkins suggested for those that were intent on counting calories that 1,800 was a reasonable amount to lose on for most women and 2,000 calories per day for most men. Note this is to lose weight, not maintain it. Obviously, some folks will be able to eat more and lose and some will have to eat less. Being perimenopausal and having PCOS and diabetes, I've found that I need to stick around 1,500 calories per day max if I want to lose. Add to that the fact that he is approaching 60 years old, which means that his metabolism is already slowing, and he may find that over the next couple of decades that he needs to eat less and less to maintain that 175 pounds and "floating" feeling that he's so fond of.
While this may seem attractive to him, it certainly doesn't to me. Realistically, I understand that as we age, our metabolisms slow and we will need to consume less calories per day to maintain a certain body weight, but I really hope I'm never in a position of having to starve myself to maintain. How depressing.
I also don't know if I can agree that we are forever doomed to regain any weight we lose because we lost it through calorie reduction, which if we're completely honest is the only way to cause our bodies to shed fat...give it less calories than it needs for BMR PLUS daily activities, but never drop below BMR. Granted, with low carb most find that they can consume more calories than they did with low fat/high carb and lose weight better (and without being constantly hungry), but even with low carb if you eat more than you burn you will gain weight or at least fail to lose. Low carb also gives you the advantage of switching your body over to using primarly fat for fuel instead of glucose, so your body is more likely to turn to its fat stores for energy than it would if glucose supply was sufficient. The question becomes, how much more energy are you expending using fat for your primary energy source than you were using primarily glucose as that is what I believe to be the heart of the metabolic advantage that Dr. Atkins spoke of?

Oh...and that "butter on the bacon" comment was totally misinformed, but given the rest of the article it doesn't really surprise me too much that he would make such a comment.