BROADCASTS.com

Although mainstream sources still mistake \u201cthe brain needs glucose\u201d for \u201cthe brain can only run on glucose,\u201d regular MDA readers know the truth: given sufficient adaptation, the brain can derive up to 75% of its fuel from ketone bodies, which the liver constructs using\xa0fatty acids. If we could only use glucose, we wouldn\u2019t make it longer than a few days without food. If our brains couldn\u2019t utilize fat-derived ketones, we\u2019d drop dead as soon as our liver had exhausted its capacity to churn out glucose. We\u2019d waste away, our lean tissue dissolving into amino acids for hepatic conversion into glucose to feed our rapacious brains. You\u2019d end up a skeletal wraith with little else but your brain and a hypertrophied liver remaining until, eventually, the latter\xa0cannibalized itself in a last ditch search for glucose precursors for the tyrant upstairs. It would get ugly.

That\u2019s adaptation. But is there an actual\xa0cognitive advantage to running on ketones?

(This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Tina Leaman)