[header] How to lose 2 lbs in one day [title] Visit the sauna. [step] One of the most straightforward ways to quickly lose water weight is to simply sweat it out. This is a short-term technique that is commonly used by boxers and other fighters to shed extra pounds before a weigh-in. 
You can make yourself sweat in any number of ways, but arguably the most time-efficient way would be to spend some time in a sauna. Here you will quickly sweat and drop water weight.