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College should be a great time to eat a TON. Most places have unlimited eating dining halls and a lot of schools offer an unlimited eating plan for just a bit more than the others. Invest in an all you can eat plan, tupperware, and a small fridge-use the school food as a supply for your dorm room as leftovers. Honestly, most places don't watch you too closely, and as far as morals go, I always figured I had a right to the food since I had unlimited swipes-it was simply a matter of location of eating it that had changed.
Nuts are a great food to keep in your dorm room as well-they won't rot, are delicious, are nutritious, and full of calories.
I play football and definitely know how hard it can be to keep weight up while in season-just eat, eat, eat.
Also, don't worry about eating breakfast/lunch alone if need be-if you're going to the dining hall 5x a day, you won't necessarily have somebody to go with you each time. Better to read a good book than not eat IMO.