Coffee is alright as long as you don't have it in excess and load it up with sugar. Beyond healthy foods, daily exercise would be helpful, if you are not doing so now. Walking 20 to 30 minutes or more per day would be beneficial, even indoors, if the weather or environment aren't ideal.
Alcohol is also very high in sugar making lots of students gain weight... Eating too much fruit that contains a lot of fructose won't help either ... Cut out starch, sugar, salt and cheese ... Grill or bake green vegetables