Your reading is simplistic.
This is talking about blood glucose levels, which is influenced by many factors, including glucose production in the liver.
This is talking about blood glucose levels, which is influenced by many factors, including glucose production in the liver.
The brain depends on a very small quantity of glucose to function - it arguably is more efficient with ketone bodies, for instance [1] - so covering not only glycolysis seems like an incomplete research.
[1] https://blogs.scientificamerican.com/mind-guest-blog/the-fat...
Also, they only fasted people for 3h. I've sucked a lot of junk out of peoples' stomachs who have had longer fasts, so this is not even a glycogenolisis phase: they could easily have been digesting food still. The participants were students, so maybe some had drunk alcohol, which, like a ketone is a two-carbon molecule...