How long does 'water weight' last?

So I've heard a lot on this site about increasing your cal intake causing you to gain water weight quickly afterwards which later goes away, but how long does that take? In the past 3 weeks I've gone from 1800 to 2200 to 2400 and according to the scales I've gained 3kg (almost 7 lbs). This just seems so scarily fast considering I was told it would take a lot more cals and/or a longer time to gain this amount of weight. Every day I am so close to relapse because of how quickly I am gaining, but I was told that it would mostly be water weight and that "next week you won't gain as much", but lo and behold the next weekly weigh in I have gained again. I must have the slowest metabolism in the world :(

arent you looking to gain weight... that you have is a good sign

Yes of course its good.  I'm just scared and confused because my dietician told me that I was going to need so many more calories than I am currently on to gain this amount of weight.  I can't cope with how fast it is happening.

I'm not sure about most people, but after almost a month of gaining pretty quickly, I have slowed down all of a sudden. [I'm not sure whether this is to do with a. my metabolism speeding up or b. the water weight thing]
I don't actually know how much I weigh, but I can sorta estimate how much I've gained, and I have been no where near as bloated recently.

I guess it varies from person to person, but listen to your dietition, they know best xD

I think that is why the first period of refeeding is so hard. One the change and two that one can gain a fair amount in a short time due to slow metabolism and water. You have to stay strong to get past this point. Try to remind yourself of the facts that it takes a certain amount to gain and you only increase by 600 a day which is good but should not equal the actual weight you are gaining. The more you go back and forth the harder it is to adjust. Try to stay in the day and focus on that. I am not sure how low your weight is or what you were eating at the very start but that can contribute as well. I know my mom in refeeding can make big jumps then to loose the next on the same. It is hard and frustarting to figure so that is why it is good to trust your nutritionist and that when you get to a healthy range it should stop because your body will be at a happy weight. Please stay strong

Thank you, its good to hear from someone who understands how hard it is. My weight is now around 90lbs (I'm 5'5") and prior to these increasing i had been on about 1600-1800 for a few months, having worked my way up from about 100 calories a day back in Jan/Feb. I find it so hard to stay stonrg - after a weigh day I end up eating around 1400 cals for the next few days because I'm so upset with the weight gain.

Abbi gave some great advice. But yea the more you go up and down with your cals, the longer it will take your body to adjust and not think you are still starving it.  I got water weight when I increased from like 200 to 1900 in a week. Iv just had to up again and I'v been getting water weight and bloating again, euch.  It is very hard but be strong and it will go away, sommetimes it takes a week other times maybe longer depending on how many cals you have upped. you have been amazingly brave to make it this far and just think of the future and what you will be able to achieve without this crappy illness.  If you are struggling and just need some support feel free to message me any time.  :)

I seem to be having the same problem.  I recently increased my calories to 2,500, and I've been experiencing a lot of bloating and swelling.  At least, I think and hope it is.  I have gained about 5 pounds in a little over a week, so that seems unlikely, but I'm really not sure because it could also be due to slow metabolism, as mentioned above.  It is scary to be gaining so fast, and it's also frustrating because I don't know if I should decrease my calories or what.  If it is just water weight, how long will it last, and how will I ever know my real weight?  This is a really hard process, but at least we all have each other to lean on and go to for support.  In the end, everything will work out for the best, and we'll hopefully be a lot happier and definitely healthier.  Just keep up the great work and don't get discouraged.  Everything is going to be fine.=)

KB don't decrease your cals, this will just set you back into starvation. The weight you gained is modt likely water weight if you have bloating and swelling!

The major increase in cals should boost your metabolism faster so do not worry.  The sooner you get them up, the quicker your body will comme out of starvation. Just ride it out.  You need to gain anyway so try and look at it as a positive thing :)