[SmileyEH]

If you know the time of the weighin you can probably add around 10% of your bweight by eating a ton of food, taking anti-diarrhea medication, and drinking a ton of gatorade with salt in the day or 2 leading up to it. Conversely you could lose around the same amount by doing everything opposite (eat nothing but prunes, get an enema, pretend to be a boxer for 2 days). So I guess a 220-180 ish swing could be possible, although horribly painful/unhealthy/unsafe without gaining or losing that much fat.