This to me is a no-brainer (pun intended), and that one needs to drink water frequently in order to have high mental performance and clarity.
The quality of water is also important, and I suggest natural spring water or alkaline water. The gut is often considered a second brain.
Let’s keep this one simple in saying fast food and sugar is typically not going to yield mental clarity. Personally, I feel clearest when eating meals consisting of high quality protein such as salmon, steak, chicken, or in the case of a less meaty dish, I’ll load up on beans and leafy greens like spinach.Read more on lifehack.org