Yes. I know math isn't your strong point, but I'll try anyways. I'll use round numbers to help.
Let's say you weigh 180 pounds. Your current body fat is 15%. That means you've got 27 pounds of fat, and 153 pounds of lean body mass (muscle, bone, water, etc).
In order to drop your body fat percentage one point, you've got to lose 1.8 pounds of fat, assuming you're staying the same body weight. Alternatively, you could raise your lean body mass enough that your current 27 pounds of fat is now only 14%. To do that, you need to increase your LBM to 165 pounds, for a total body weight of 192.
1.8 pounds of fat requires 6300 calories to produce (or a deficit of 6300 in this case). For simplicity sake, we'll assume that you require 2500 calories for maintaining your current body weight (basal metabolic rate, plus any activity). Over the course of a week, that would mean eating 900 calories under maintenance, or 1600 every day. That's a pretty severe caloric deficit.
The other option is putting on 12 pounds. Under completely ideal circumstances, a male can produce 2 pounds of lean muscle a month. Those circumstances would be someone who has never weight trained and has an impecible nutrition plan and weight training plan. That's 1/2 a pound of muscle a week. That leaves 11.5 pounds of "other" lean body mass, which basically amounts to water.
But you were talking about a weekend, not a week. So that gives 2 days for all of this. Even combining both, you can see how ridiculous that is. Body composition changes don't happen in days. They happen in weeks or months.