I don't think humans manufacture Sat'd fat directly from carbs...ruminants do however. I'll have to double-check that.
I was re-reading Protein Power: Lifeplan and Dr's Eades make the point that the Hunter-gatherer lifeway is only about 40K years old. Prior to that it was big-game hunter (hunter-hunter?) for nearly 1million years. Analysis of enamel from H. Erectus, H. Neanderthalensis and archaic H. Sapiens show very little plant material consumed. At those times only select areas would have supported much vegetative material but the point that Cordain made in his re-analysis of the ethnographic atlas was that it would be energetically impossible for plants to play a major dietary role, at least from a caloric perspective. To be sure they played some part with regards to vitamins and minerals but even that may be over-stated.
I think this also brings up an interesting point that we have tossed around quite a bit: How much carbohydrate intake is healthy relative to energy expenditure? What type and level of exertion reflects ancestral lifeways?
Cahones to the wall athletic training virtually guarantees the need for some dense carb sources. Although I've been wondering what role high glycogen organ meats (liver, heart, tongue) might have played in "post workout nutrition" as these are universally eaten first when a kill is made.
"Survival will be neither to the strongest of the species, nor to the most intelligent, but to those most adaptable to change."