After 6 weeks off the bike during which time we had a bad flu, asthma, and giardiasis all at the same time, and maintaining what some would call a high carbohydrate diet, we led a 2.5 hour ride on the tandem this past Sunday. We mostly kept it down to VT1 - we had 5 minutes in zone 3. We each took in about 50 calories of carb/protein mix at our "lunch stop." Otherwise we didn't eat anything and had good power all the way, in spite of being way out of shape. We were obviously not keto adapted. My point being that it's not necessary to be "keto adapted" to be keto adapted, i.e. able to burn fat for energy on a long bike ride. It is necessary to have a history of doing long bike rides. I'm not sure that how one eats off the bike has anything to do with it, see the many posts of greg83 on this subject.
I see the word "science" in that book title. Do you know of any RCTs of competitive cyclists showing that their off-the-bike diet changes the fuels they burn on the bike? I know that various TdF competitors have tried eating alternative diets but have found no favorable results, nor has their been any rush I've heard of toward alternative diets among the pros. Among RAAM riders
most riders aimed for the standard proportion of 70/20/10 with respect to carbohydrates, proteins, and fats.
and ate an average of 72% liquids. Strasser used almost exclusively liquids.
www.jmvelez.com/images/nutrition_raam.doc