As i mentioned in a few posts back, food is very important (always) but also when studying. Your brain uses so much energy just keeping you alive, thinking, functioning and then when studying and having to memorize things, learn things and study, that also requires alot of energy.
It is said that the brain uses roughly 800kcal a day just to keep your alive and functioning. And then of course your body and breathing, moving and all of that burns calories all the time. I don't want this to get you thinking "calories being burned" or think you have to get up every 5 minutes just to burn more calories. But I am just saying it how it is, your body burns energy all the time keeping you alive. Hence why it is said that you should never eat below your BMR (as that is your basic metabolic rate and what your body burns each day keeping you alive). And then there is your TDEE which includes your activity levels as well.
But back to studying, you may be sitting for long periods of time. Especially when it comes to exam time and you need to spend hours a day and studying and most of it is spent sitting. But that is ok!!! You still need to eat even if you aren't as active. There have been days I've had so much to study that I don't even have time to workout but that is not a cause to eat less, the brain is the most important and you need the energy and fuel so you can study.
Think back to when were eating very little (or compensating for what you did eat), did you really have the energy to concentrate or study or even remember what you learnt? And if you are still stuck in the eating too little, then ask yourself has your studying ability decreased? Is concentration harder? Focusing and studying more of a battle than before and memory feels long lost. That is because your brain hasn't had, or doesn't have the energy to study or focus clearly.
It was also shown that when a person is starved of energy and the body is starved, then the mind goes into a sort of starvation brain (a post about this is on my blog) and making rational decisions, thinking clearly and remembering things as well as many other tasks are very much reduced. This is why you can feel scared of certain foods or think eating an apple will make you gain weight, it's not rational thinking but because the brain is so starved of energy you can't think rationally or even make clear decisions. Also why you might be very indecisive.
Your body always needs energy no matter what you do. And if you want to function properly and get the best our of your studying then eat and drink right.
Foods such as dark chocolate and almonds are supposed to be good for studying and foods with omega 3&6 ate good for the brain so walnuts, oils, salmon etc even eggs are supposed to be good. So make sure to have with you snacks when you study, foods that will give your body and mind the right energy. You don't need to sit and eat cakes and cookies while studying (unless that is what you want), because the sugar will give you a "spike" of energy and then a blood sugar drop leaving you cranky, tired and hungry. So instead keeping the blood sugar stable while studying and having lots of water is important! My best advice is also to not get addicted to caffeine, it feels like coffee and redbull are sort of romantisized and all college students are addicted to it, but if you can... try to not start at all. Trust me, life will be better without a caffeine addiction and you will have more energy rather than relying on a subtancd to give you energy :)
Also tip, pack with you snacks and lunches. I can recommend making home made raw food bars or granola bars, healthy muffins or cupcakes or even simple banana and egg pancakes which are easy to make but good things to pack with you to snack on. And also vegetables and fruits, nuts and dried fruit are good as well :)
Remember, even if you spend hours sitting your body needs food and energy. And when you spend hours studying then your brain is working hard and needs the right fuel. :)