http://www.bodybyscience.net/home.html/?p=1054 got me thinking.
"You select out for the resilient and discard those who are less adaptive, all while assuming that the training produced physical superiority rather than realizing it simply identified superior physical adaptability. There is nothing wrong with this marketing approach, but when it comes to advancing training science it ignores the plight of the non-responder."
The same thing happens with any one type of diet. That is why LCHF works so well with those who do not respond to SAD, or the ELMM, or moderation approches.