@Dr. Harris and for clarifications;
Dr Harris; "It makes absolutely no sense that neurons only start using ketone bodies under nutritional stress- glucose shortage - if that is the "best"
You are making a huge and false assumption; that glucose shortage is equivalent to nutritional stress. The brain's use of ketones may be very natural and likely much more prevalent during much of our evolution, and indeed our human brain did not likely evolve on glucose…see 'Expensive Tissue Hypothesis' cited several times. The brain uses ketones when they are available, i.e.when glucose is not.
You say I said, "It makes sense if excess sugar is poisonous to the body."
I do not believe that came from me, though I do not necessarily disagree with the statement.
Dr. Harris; "You are suggesting that the brain only uses glucose as a favor to buffer us from excess glycation?"
I do not know that that is what the statement was suggesting if I didn't say it, however that is not altogether a bad reason…but not the only reason. The brain burns lots of glucose when it is available because it can and when the subsequent toxic effects are not severe enough until after we have had a chance to reproduce, preventing evolution from having selected against it, and where the effects of burning it, such as reduced glycation, offers benefit.
Dr. Harris "If that is so, why does it [ketone burning?] stop at 60% of energy needs."
Dr. Harris; "Why use any glucose at all and why make the liver engage in GNG to provide it - using precious energy while you are starving?"
For the tissues that need it I suppose…it takes energy to stay alive…
Furthermore, I suspect that it takes far less energy to derive the necessary glucose via GNG from glycerol or lactate than having to eat and digest it from starches when not starving.
Dr. Harris; "PP BG increases do not cause hyperinsulinemia."
Wrong. Have you ever measured glucose, insulin and insulin resistance in people before and after eating. If you had, I do not think you would make that statement. Glucose and insulin will spike after eating starch, insulin following glucose, particularly rice and potatoes, in some more than others, in those already quite resistant, and those not very, and will do so often to a greater degree in a child that has not yet had much chance to become insulin resistant. In fact some believe, including myself, that cells become resistant to insulin, partially to help protect from intracellular glycation. The major damage from glycation occurs in those tissues where glucose entry is largely not mediated by insulin such as nerves, endothelium, basement membrane of kidneys, etc seen so regularly in diabetics. And talking about stress; raising glucose raises insulin, raises leptin, and this stimulates the SNS…raising glucose..
Dr. Harris; "Pathological insulin resistance causes hyperinsulinemia [rather than PPBG]."
Incomplete. What causes the pathological insulin resistance? Glucotoxicity of receptors, overuse of insulin receptors that cannot be recycled fast enough, fatty liver secondary to hyperleptinemia, etc..
You say I said, "There are no redundant systems in the body to control for blood sugar except utilisation, so ... you must utilise it to get rid of it."
Where is that said?
Dr. Harris; "The liver is a large and flexible buffer that in normal people can soak up huge amounts of glucose."
Yes…and your point? Isn't the liver utilizing it then?,,,and doesn't it need instructions to do so? and isn't the liver one of the first and main organs that becomes dysfunctional with insulin and leptin resistance?
Dr. Harris; "All of these systems demonizing dietary carbohydrate fatally conflate glucose as a cellular fuel with glucose in the diet. Hyperglycemia and subsequent glycation is caused by failed glucoregulation, not dietary glucose in "spikes"…"
Hyperglycemia happens after one eats starch/glucose. It is made worse by failed glucoregulation that elevated glucose/spikes in glucose, spikes in leptin helps to cause.
Dr. Harris; "Why did we not evolve to be more independent of the need for glucose at the cellular level?"
To have an anaerobic fuel supply…for fight and flight..
Dr. Harris; "it [glucose] is valuable. Our neurons literally die without it. Period.The reason the brain can run partially on ketones is SO THAT IT CAN LAST LONGER ON LIMITED GLUCOSE WITHOUT DYING."
Since you apparently are still misunderstanding what I and others are saying, and since you like so much to capitalize so we can see better; NO ONE IS SAYING GLUCOSE IS NOT VALUABLE OR NECESSARY. All WE ARE SAYING IS THAT WE SHOULDN'T GO OUT OF OUR WAY TO EAT IT.