Holiday dieting

As the holidays are coming up, last day of school tomorrow to be honest, I thought I should set some goals for the next two weeks. I want to at least weigh 39-40 by the end of these two weeks. I currently weigh 48.2 and feel this is the only thing really keeping me "here" if you know what I mean. So I can either have the choice cut down on food or exercise constantly, why do I have the feeling I'll be doing both?