Here's some advice from a nonmedical professional on staying healthy: it's hard to do, especially as a college freshman, but it is possible.Actually, I really believe there's a lot of luck to it as well.
Students need to eat well in college, first of all. There's a whole lot of junk food going on, which may lead to nothing positive at all. College dining spots really do have decent foods such as yogurt and salads, as well as sources of protein. Another thing students should do is depressurize with some healthy walks or time at the gym. They need to escape, if just for an hour a few times a week. Also, it's nice for socialization.
To me, the most important type of healthy is mentally healthy at college. That comes with an ability and determination to stay on top of assignments, keep up with reading and taking good notes. However, there are multiple causes of stress in college other than coursework. There are roommate issues and socialization issues that can be painfully difficult. There's homesickness and regret about not going to XYZ school instead. Seek out one or two activities that help you meet people with whom you have things in common, but don't over commit. Remember that college doesn't last forever. Enjoy! If it's not going well, consider time abroad or even possibly a transfer.