you can't do that, it is very unhealthy and you might even die. you should start to exercise and lose weight slowly, when you lose weight slowly you will keep it off longer. in the mean time just be happy to be alive and enjoy everyday to the fullest.
Unless you have surgery...but you can start losing weight right now by cutting out white bread, white rice etc and replacing with grains, and start having lots of fruit and veg and get moving, start by walking a block, then running a block....if it's too cold you can walk around the mall several times or hire a running walking machine and put in front of the TV etc.
A person can't gain that weight in two days and they won't lose it within two days either, sorry. Eating right and exercise is what you have to do. It'll take time, but its a tried and true method that gives results.
You would have to sweat sweat sweat...it's only water weight you would be losing and it'll all come back the next day.::but this is even hard for pro fighters to do ..very unhealthy! best way to lose weight and keep it off is diet and exercise so you lose about 6 lbs every 2 weeks!