First, good luck with college! Learn as much as you can and meet lots of new people. I'll be a junior in college this fall, and I'll try to give you some advice based on what I've done during the past four semesters.
Based on what I've seen, the food on campus is pretty lousy, just as you described. Cook on your own as much as you can and buy food that works for you, financially. Grass-fed meat and pastured eggs are great, but if you can't afford them, grain-fed stuff is still a heck of a lot better than cookies and cereal. I've been living off campus and have had long days in the week where I'm on campus from 8-5. What works for me is to cook a huge breakfast at home (Ex: bacon and eggs) and then bring some smaller snacks (nuts, berries, cheese, etc) to keep me full until I'm done.
As far as exercise, I'll tell you what happened during my 1st semester, before I had ever heard about primal. I ate lots of awful food (even bad by CW standards), drank lots of beer, and probably averaged about 6 hours of sleep (from both studying and partying). The result? I lost 10 lb that semester, from 215 to 205. How'd I do it? The wise people in charge of Texas A&M decided that freshmen had to park in a parking lot about 1.5 miles from all the buildings with my classes in them. I walked A LOT.
If you don't have time to go to the gym, that's fine. Just walk as much as you can. Take the long way every once in a while and enjoy yourself. One of my TA's transferred from Berkeley, and he said that it's a beautiful campus. Just make healthy living a priority for you, and good health will happen. Again, good luck!
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