LOL, it is interesting that you bring this up because I am finally losing the weight I put on in my fourth year of dental school, and that was in 2004! I started dental school at my "normal" weight, and gained about 10 - 15 pounds each year that I managed to take off by working out during summer vacations. I never tried to take off those 10 pounds from senior year which crept up to 20 pounds over the next 4 years until last month when I finally said "Enough with being lazy, stop the take out, eat a piece of fruit, cook something in the kitchen, and GO TO THE GYM IMMEDIATELY!"
I attribute my weight gain to emotional eating. I would feel stressed all the time about having to do well on exams (although I didn't show it), and as a result I felt that eating made me happy and was something I looked forward to after a long rough day at school. I used to be too tired to come home and cook something, and the thought of just picking up some hot take-out sounded a lot easier and comforting. I didn't want to spend time going to the gym because I felt I could better use that time after class to relax or nap before I had to hit the books and start studying later again at night. In third and fourth years, my friends and I used to go out a lot on the weekends for fun - food, alcohol, mmmm more calories. My fourth year I got stressed with applying to specialty programs, and that stress never really lifted until I got accepted (2.5 years later) and got settled into my new location and life in the program (another 1.5 year), which brings us to last month when I finally got fed up and went to the gym. I don't have to worry about studying anymore so I have zero excuses now. I've found that working out is a lot easier in residency that it was in dental school because I have a lot more time and very little stress.
Eating and ignoring the gym was just how I dealt with stress. There were plenty of people in my class who would hit the gym daily and swore it was the key to de-stress. Not me. 😀