It is nothing wrong with not being a scientist
, don’t even worry about that.
Please don’t take Dr. Rosedale seriously; he is from ‘snake oil’ guys.
If MD could say the statement like this: “Blood vessels constrict, glucose and insulin can't get to the tissues…” - stay away.
Let me explain the situation with glucose and the brain in this way.
Brain cells are highly specialized cells. Because of their narrow high specialization they lack (relatively) some components or chemical machinery to do things which are possible for more simple cells.
Extreme vulnerability of brain cells, esp. neurons, is a part of the deal; the price of being so high specialized. There is no way for brain cell to use ketones or modify fat for energetic purpose. Ketones are highly toxic and cause the brain tissue damage, irreversible by the way.
Among brain cells, only astrocytes have some reasonable storage of energy (glycogen) as some kind of energetic ‘back-up’ (for 15 min. max), but it mostly used for catastrophic events, but for second-to-second brain maintenance. Other cells used glucose only from constantly running supply, and if the supply interrupts, then start of their structural changes begins within couple of minutes (!). Turnover of glucose is so fast that there is no even time for converting fat (on site
, if it would be even possible) to usable glucose.
Brain loves glucose, it tolerates it well up to 1000 (!), in vitro
of course, the point is: more (usable) glucose – faster recovering brain.