Eating is an American pastime, a survival instinct, and trust me when I tell you it is a necessity to make it through high school with your psyche intact.
All day people tell you to do assignments and think about schoolwork. This is exercise, whether you think about it like that or not.
The fact is that your brain uses 25% of the energy your body produces. That means to keep it properly functioning you need to give it what it needs.
Eat! Healthy food, unhealthy food, doesn’t much matter when you are working to the edges of your body and mind’s limits. Just keep shoving food in your mouth and keep thinking, otherwise you find yourself irrationally angry, irritable, cranky, tired, and generally low.
Eat at all hours of the day, to keep the all important organ that is your brain running at its optimal level.