I tend to skip meals during exams to avoid getting sleepy and by the end of exams turn into my highschool self.
Are there foods that I can eat that can give proper nutrition and aren't too heavy ?
Eat Light food before exams and moderate amount of water(only so much that you can hold)
Avoid Fried foods or dishes with too much oil/fats, if you eat heavy food before exams your stomach would use up much of available energy in trying to digest it and result in very less available energy (negative energy food)
Fish (freshwater) is good due to the Omega 3 Fatty acids (stimulate brain functions)
Grams and Dal soaked overnight, Dal Roti, Lassi/Nimbu Paani etc are good too
Basically any food that is easy to digest, has a positive energy ratio and fills your belly is good enough
Don't skip meals during exams, its counterproductive