As spork mentioned, managing blood sugar levels is important. Eating whole foods helps with fiber and nutrients. On a concentrated thought day, I might add both sliced avocado and chopped nuts to my salad to boost energy to brain. On a meeting heavy day, the salad gets either avocado or nuts, not both, but I’ll add extra radishes and cucumbers. I don’t cut calories to the point that I’m hungry all day, since that tends to lead to drive throughs, fries, and shakes.