"Mental clarity" means having a clear and focused mind. It is when your thoughts are not confused or cluttered, and you can think and concentrate easily. Full definition
While current research shows that eating breakfast doesn't affect your weight (1), it may be important for improving mental clarity in some people (4, 5). (alivebynature.com)
This consistently heightened level of mental clarity only improves over time. (vespapower.com)
For this reason, fasting is associated with increased mental clarity, focus and concentration. (wellnessmama.com)