Anywhere from 6-10lbs. I don't eat nearly enough salt so my water weight gains/losses are really severe.
Once it's over I usually spend the two days after peeing every 10 minutes, and usually end up a pound or so below where I started. It's always surprising since I gorge on sweets during my TOM. I bought a key lime pie last TOM and spent the whole week just pulling it out of the fridge (not even cutting a slice! Oink oink, I know...) and going at it with a fork until I got sick of it. It lasted 6 days and didn't seem to have any ill effects.
God forbid I eat a friggin' steak or something though. I'll gain three pounds that night and never lose it.
I have always been really lucky in this area and never notice a change in weight! I have always been told that my clothes would feel tighter and I would feel bloated and might gain a few lbs, but never have.
My mood on the other hand, that's a different story......
TOM came to visit today... and I'm up about 2 pounds... Usually that goes away after the first couple days, and then I actually go down a pound or two... because I do my best to stay on track as much as I can during TOM.
Honestly though, I don't know how much I gain during my period as I've never really tracked it through one, hopefully this time around when I'm more dedicated I'll notice!
I absolutely avoid the scale at the time so I don't even know if I gain it or lose it or what. But I know I must gain some water weight because i pee like crazy for the next 2 days after its over.
i gain and average of 5.5-6 pounds. It does come off quick but i have to be even more cautious of what i eat to make sure it all comes of and then some after the TOM!