Brain uses both. There's an interesting talk [1] about how brain's ability to use glucose lowers before Alzhaimers disease and others. There seems to be some l

Brain uses both. There's an interesting talk [1] about how brain's ability to use glucose lowers before Alzhaimers disease and others. There seems to be some link between brain diseases and glucose metabolism. [1]: https://www.youtube.com/watch?v=XxGiQ7YrUYE https://www.youtube.com/watch?v=XxGiQ7YrUYE