Bullet coffee: could it be inappropriate for the brain?

https://www.jci.org/articles/view/149371

However, it is favourable for your metabolism. Low carb diet maintains low insulin and leans toward lipid catabolism to meet energy demand.
Perhaps tea affects less the metabolism of non-neuronal cells. 
Tea with butter as Mongolian people drink is perhaps the best combination (https://www.eater.com/2016/8/25/12624068/butter-coffee-tea-tibet-yak).

https://www.nature.com/articles/d41586-022-01487-4?utm_source=Nature+Briefing&utm_campaign=4e7292f95e-briefing-dy-20220811&utm_medium=email&utm_term=0_c9dfd39373-4e7292f95e-46366554