Exactly Julie. The huge individual variation is IMO telling us that the mitochondrial defect IS hackable. Something in my body is (partially probably, not completely) compensating. Yours wasn't until you found the work-around and now it is.
Or some of us have genetic predispositions or protections against our inherent cerebral glucose deficiency. For instance, I suspect I have some GLUT1 issues I haven’t pinned down yet. On the other hand, I suspect you (and others here) have some protections. Hence, some of us need to "hack" harder
Circ, I think you’re correct. Some parts of our brains NEED glucose exclusively, maybe 35%? I’m guessing that figure based on my notes from Dr. Cunnane’s talk below. FWIW, the minuscule amount he’s suggesting we achieve, 0.3-0.5 mmol/L, is to compensate for our cerebral glucose deficiency not to entirely replace glucose as our primary fuel. Even those of us who are leto-adapted are typically reporting very low levels, below 2.0 mmol/L. From my understanding this isn’t an either/or proposition, but rather a both/and.
His research has demonstrated that ketones can maintain up to 65% of brain fuel requirements when glucose can’t be utilized effectively. As Martha shared earlier, he stated that using ketones does NOT inhibit your ability to be able to use glucose simultaneously or at a later time. Babies begin life in ketosis. We all shift to a ketotic state during sleep. Our brains are very well adapted to using ketones and shifting between using glucose and ketones as fuel.
I think the carb night suggestion was more of a metabolism "re-set" rather than a glucose re-feeding period. The ability to seamlessly shift back and forth between different fuel substrates is indicative of optimal health- remember Russ's variability theme? Additionally, we have lots of suggestions that the E4 allele was designed for long periods of fasting which would have naturally resulted in ketosis. IMHO, the "hacks" we're working on with dietary/lifestyle ketosis should be seen as a means to restore a broken system to regain that metallic flexibility.
