In the Buttermind experiment influenced them to start adding butter to their coffee. In this excerpt, they say that their cholesterol went down 25 points during the period they drank it (their lives changed in many other ways at the same time). At the end they say:
Later, we would learn that Ethiopian warriors had drunk buttered coffee to energize before battle as far back as 600 CE. But that was after we had stopped regularly drinking it. When we transitioned out of the Marine Corps and our days became less frenetic, it just didn’t seem as necessary.
The mention of Ethiopian warriors reminds me of how, after discovering that pork fat (from pork belly) improves my sleep, I learned that Mao Tse-Tung praised a certain pork-belly dish (红烧肉), calling it “brain food”. I don’t drink coffee but I have tried tea with butter. It tasted good, but I didn’t like the residue it left on the tea cup. Cream doesn’t leave a residue. I haven’t noticed that butter gives me energy. The benefits I believe in are better brain function and better sleep. Maybe more calmness.