Is it possible?

Is it possible to gain a pound in one day?

Is it possible to lose a pound in one day? I know I have before but was it just water weight or really the stuff i'm trying to lose?

How can you tell if the weight you lost was water weight or not?

you can only gain 1 pound a day if u eat 3,500 over and you can only loss a pound of fat if you have a defict of 3,500

Well, if you eat OVER 3,500 calories in one day (taking into account how much you've burned), sure you can gain a pound in a day. Same with losing a pound in a day. OR, if you meticulously keep track of what you've eaten for a week and how much you've burned and you've gone OVER you'll gain a pound (or more). As far as, how do you know what's fat and what's water -- I don't really know what to say because I think only a scientist would need that kind of information. If you go for a few weeks or a month and the scale stays down, then you probably know that it's fat and not water. But in one day, it's really not possible. I would never count what happened in one day and I would never try to decide whether 5 pounds was fat or water because bodies naturally will fluctuate that much day to day. 

I'm not an expert, but I know my weight can fluctuate from day to day. I've been told not to weigh myself daily, because you can see that fluctuation and it's depressing. I judge if I'm at a weight and it stays there. I'm trying to wean off the frequent weighing to once a week. If I feel particularly bloated I won't weight myself because I think it will be water weight.

you can lose a pound in a day, and yea it can be water on some occasions.  The only way I can tell if its water or not is if my hands feel poofy.  My ring is tighter on days i have lots of water in me.  Those are the days I weigh more and its no biggy because I'll just pee it out by noon :)

Gaining a pound in one day?  Um.. well yea.  I mean everyones body is different.  So lets say you were starving your body and then ate over your normal calories, your body would hold onto those for dear life... thus gaining a pound.  Heck even 3! Just depends.

The scale number increasing/decreasing is much different than actually gaining/losing actual weight.

It's not that you lose or gain the lb in that one day, but that the scale doesn't always keep up with what is going on in our bodies.

Also, if your scale only weighs by whole pounds, you could have been losing or gaining small amounts but it just took a while to add up to one lb.

u can gain a pound in a day but its not fat. its most likely water weight (or waste weight)

oddly enough, the best way to get rid of water weight is...to drink more water. by the next day it would be all cleared out.

Weight fluctuates from day to day.  It's best to simply record the weight and watch the green trend line on your weight chart over time.  As long as that green line is slopeing downward, you're doing fine.