Well when i was at uni in my final year i put on loads of weight coz all i was doing was constant work and eating bad food (take aways etc). For the last month i have just been eating healthy and ive nearly lost it all already!
One of the worst times to eat is at night or just before you sleep because you dont do anything to help work it off (like walking etc).
Greeney is right just get more exercise, the gym is good but can be expensive, i also play football 2 or 3 times a week which helps.