After downloading and reading the article, I have to agree with Arkie's assessment. Since they recognize that abnormal AEC levels were much more pronounced in the presence of uncontrolled hypertension and elevated HbA1C levels, how they came to the conclusion that limiting dietary protein was the answer is beyond me unless they were coming from the mindset of "we can't get tight blood sugar control with the current dietary recommendations, so we'll recommend dietary protein restrictions instead." The article also does not mention what the daily carb intake and average blood sugars of the study participants were.
Decreasing dietary protein would mean by default that something else must be increased to maintain an adequate daily caloric intake; either carbs or fat. Since there is such a huge fat phobia, that must mean that daily carb intake would have to be increased. This is supposed to help??? I'd also like to point out that as a type 2 diabetic, I was on a diet similar to what they are recommending for several years and all it got me was more weight and my blood sugars and blood pressure out of control with a need for medications to get them back in line again. Since low carbing, I am off both of those medications and maintaining a normal blood pressure and an average HbA1C of 5.3 (it was 11.8 when I began low carbing). I also have my liver and kidney function tested every 6 months and so far they have been nothing but normal.
I also have to comment that getting 60% of your daily caloric intake from protein is probably too high. Generally, I get about 30% of my daily caloric intake from protein, 3-5% from carbs and the balance from fats.
Dr. Bernstein also uses his dietary approach for all of his patients and if they were all developing kidney problems, I'd hope that he would have re-thought his approach long ago (or been sued for medical negligence) and there is no mention in his book (or even cautions) of developing the types of kidney problems addressed in this article if carbs-and therefore blood sugars-are tightly controlled . As for the "super kidneys" comment, when it comes to something like this, everyone pretty much reacts the same way to the same type of diet even if some may take longer to develop problems than others, I would think that 40+ years would be long enough to see if something untoward was going to happen.
Goodness...if my kidney function and health are still as good as his in 40+ years, I'll be one happy 81 year old!