I agree, it is frustrating, to think that it should be one way or another, but what is working for me may not work for you. There are many reasons for this; we all have different genetics, have different environmental influences on what actuates our genes, different physical activity levels (do you bicycle at the speed of light as Larry Oz or meander down the road as me), are you young or not, do you eat FRESH and chemical free food or eat the food as our chemically dependent society produces, does your doctor have AND use the knowledge of using less pharma on you (they are not all knowing and some of them don't know that and some of us don't know that), etc!!!!!
Personally I have read the initially referenced books from this thread as well as others of more recent pub dates ( that have been more recently published and are more up to date with current research and say the same thing as those earlier referenced books)....I'm out of breath with saying all this, but really you have to become informed with current research/thinking and decide what makes sense for you; that is, what works, which may take experimentation along with becoming informed as you have been doing. (Disclaimer -actually a confession?-I worked as an assistant in sugar research for years in the late 1970s with my salary paid for by a major sugar company so I think about all this alot).
One really good thing we all have going for us here on this forum is that we are sharing what we think and how it is working for us not just in our normal lives, but as an ultra athlete.
Edit: I want to add that I am currently reading a book that is a rebuttal to the LCHF movement (The Low Carb Myth by Ari Whitten and Wade Smith, MD), and also that for me the LCHF diet seems to be working for me. Reading this book just to get more informed.