Brain power is characterized by how alert, energetic, and concentrated your brain is in response to a task. Information in your brain passes through neurotransmitters, which are manufactured by the nerve cells using precursors. Different neurotransmitters will have different impacts on your brain activity. For example, serotonin is the calming neurotransmitter that usually makes you more relaxed, drowsy, and fuzzy-headed. While dopamine and norepinephrine are neurotransmitters that make you more alert, more attentive, motivated and mentally energetic.
Food affects your brain power by affecting the production of neurotransmitters in your brain. By supplying amino acids, which are used as precursors to manufacture neurotransmitters, and by affecting the entry of the amino acids into brain, foods can have a significant impact on your brain activity. High-carbohydrate foods in general tend to subdue brain activity. Protein foods, on the other hand, can counteract carbohydrate food induced sluggishness. In addition, foods and herbs can have effects on brain activity by affecting blood circulation - the supply line of oxygen, nutrient, and hormone to the brain.