I went to college for one year living on campus and I actually lost 15 pounds. I wasn't trying to gain at the time, to be fair. But with all the walking across campus, stress from difficult classes, executive dysfunction, and trying to understand who I was, even the unlimited food in the dining hall wasn't enough to keep me from losing weight. I was also a lot more susceptible to people's criticism of me at the time, so getting praise for the accidental weight loss was also a factor.
If you're here and you know you want to gain, and if you have a meal plan through the college, you may have a good chance of gaining quite a bit, and going to college is a reason a lot of people won't give you too much criticism for, if that's something you care about.
Good luck with your gains and your classes!
1 week