Of course, carbohydrates, a lot of water and fish. Fish contains polyunsaturated fatty acids. These are essential fatty acids that are not synthesized by the human body (!) And get into it only with food. They are also called Omega-3 and Omega-6, and their complex is vitamin F. There are five of them: linoleic, linolenic, arachidonic, eicosapentaenoic and docosahexaenoic. In addition to fish, they are also found in nuts and sunflower seeds, in linseed oil, etc. In addition, try to eat a variety of foods, so you will protect yourself - the body is well versed in chemistry, it knows what and in what quantity needs to be taken from food in order to make up for losses, including those associated with enhanced brain activity.
You know, sugar for the brain is certainly good, but if you really lean on it, allergies, edema and other unpleasant consequences may occur. Including an excess of sugar can cause apathy, laziness.
First of all, our brain needs water - the brain is 90% water and consists. I won't talk about the notorious 8 glasses, but replacing all drinks (except, perhaps, morning coffee) will be very useful for you.
The next step is energy for brain activity. These are carbohydrates. But you don't have to eat sweets and fast food. It is enough to add 3-4 intakes of complex carbohydrates per day (oatmeal, buckwheat, durum pasta).
Further, the digestive tract works well - the better it works, the less distraction and less energy is spent on digestion. For its good work, fiber is needed - fruits, vegetables. 3-5 fruits and vegetables a day and healthy digestion are guaranteed.
Coffee is, of course, a good stimulant. 1-3 cups a day is quite normal.
Eating during exertion never falls to one single product. The balance is important, in which your brain will receive all the necessary trace elements, water in sufficient quantities. Good luck :)
Sugar. A lot of sugar. Best in natural form. Berries and fruits pureed with sugar. Jam. Honey. Bitter chocolate.
Coca-Cola bars, though full of sugar, are packed full of other pests.
Sugar. A lot of sugar. A LOT of sugar. For mental stress, glucose-containing foods such as chocolate and cola are very useful. Eat lots of bars and drink tea and cola. This all increases your activity, not only mental, but also physical, so periodically do exercises and warm-ups. Run for example. It is very important not to gain weight because of the high carbohydrate intake.