I gained 5 pounds my first semester, probably from the late night trips to Subway & all the baked goods.
I also gained 5 pounds the summer I was in summer school - no doubt because one sister I was living with drove any distance more than a block (and hey, if she's going my way I'll take the ride) and because another sister was dating a Pizza Hut delivery boy who brought us lots of leftovers. Once those 2 things were removed, the 5# went away.
"Secretarial spread" (even if you're not a secretary) is far worse and more prevalent than the freshman 15.