Why would you think it’s appropriate to comment if you’re host guessing? Your reasoning is correct in that we do eat brains, and of course they don’t get us high.

You’re wrong is the fact that brain is mostly fat. That’s incredibly misleading. The brain is entirely nervous tissue plus supporting things like vessels. It does contain lots of myelin which serves to insulate axons, since nervous tissue is electrical. Myelin happens to contain a lot of fatty acids, but it is in no sense “fat”.