I have had a challenging semester, and I've studied more than ever before. I overworked myself a few weeks ago because of having 6 tests in a two week period, and toward the end of that time I had a couple of episodes where I lost my focus completely. As a result of this, I did not do as well as I'd hoped on my Calculus midterm.
This past week, I had to prepare for 4 tests in about 10 days, and I felt the same thing happening. I had a really strong desire to buy some mixed nuts, which I used to eat frequently, but haven't had for a while. I bought some, and after eating them I felt like an intelligent person again. I believe that I did very well on my Physics test this morning, and I have had no problem doing triple integrals and changing variables this afternoon.
I have nothing to go on besides my experience and the knowledge that nuts contain various amino acids, minerals, and healthy fats. A quick search of Google didn't turn up any definitive, reliable sources, but several people made unsourced statements that eating nuts helps cognitive functioning.
Does anyone have academic sources that support this hypothesis, or similar experiences?