how long will it take?

So for the past month, I basically heavily restricted my diet to about 900 calories a day, sometimes more, sometimes less, so I could get to my goal weight of 120 lbs by the time I go to school in September. Realizing this wasn't good for my body, I decided to bring up my caloric intake to about 1200 a day so I'd be quite a bit healthier while still losing weight. After two days... I weighed myself (I have an unhealthy obsession with weighing myself every day, which I realize I need to get out of) and I was 3 lbs heavier than I was the day before!

I'll take into account that my scale, which is digital, might have underestimated what I weighed yesterday, or overestimated what I weigh today. I tend to step on the scale two or three times in one weighing to check to see if it miscalculated the first time if my weight seems ridiculous.

I figure it's just water weight, as I did drink a bit more yesterday, plus that I'm eating a bit more so my body is in the process of getting used to it. My question is, how long should I expect my body to take to get used to the higher intake and start going down again? Any input would be highly appreciated =D

It could take a few days but you did not gain 3 pounds. Unless you ate 10500 calories ABOVE your BMR then you gained 3 pounds. Kinda hard to do unless you really pigged out on some seriously unhealthy food. Maybe after your body recovers from you not feeding it enough you can up your caloric intake even more to say 1400 - 1500.  Try to get a deficit of 500 so you can safely lose the weight. 1 pound a week. You might not get there by the time school starts (you never gave current weight) but at least you won't be all sick and stuff.

Thanks for the reply =] I weigh 129 lbs as of this morning, but I think I actually figured out why I "gained" so much xD I completely forgot: I'm getting my period in a couple days! Plus, I looked at my sodium intake, and it was much higher than my norm. My average is between 1300-1500 mg a day, but yesterday I had 2300 mg of sodium, so those two things added together I think I'm retaining a LOT of water xD I think I'm freaking out over nothing...

I HAVE to use an analog scale, I just don't trust the digital ones! It's something about lowering myself onto the scale and watching the needle rise to where my weight is...it like preps me for the final number. There's something just so cold and scarey about stepping on a scale and having it throw a number at you lol!

Maybe go on a scale diet for a week, and use a bodyfat bio-electric impedence moniter instead? Omron makes one that's like $20. It measures your bodyfat percentage, so you can monitor your weight loss and lean mass gain and your overall progress, so you don't get stuck on arbitrary numbers on the scale. And they are arbitrary, because you don't know how much of that weight is skeletal mass, muscle mass, organs, water, waste, partially digested food, etc. At least with the Omron thing you will know fat vs. all other mass. They're not the most accurate things in the world but they will at least let you feel like you're checking yourself still without getting hung up over an even less accurate number (weight).

PS: notice how I addressed you stepping on the scale as the problem and not the 3lb weight gain?

I look at the 3lb weight gain as a symptom of the real problem, which is the scale obsession; you will think that by eating 1200 calories you are causing yourself to gain weight and this will only frustrate and discourage you.

I know.. it's definitely a problem I need to work on. I haven't weighed myself today though, and I'm sticking with 1200 calories for now.

I see fluctuations of up to five pounds sometimes, and I weigh everyday.  What i look at is the trendline on this site, and if i see a gain and havent have the amount of calories needed to pack that on, i know its water weight or that i had heavier food the day before which i havent fully digested andc gotten rid of, and thats causing the number to go up.  This is all even when i stick to the same amount of calories every day, and i think its perfectly normal.  I would suggest just not stressing about it.  If you see a loss then use that as positive reinforcement to motivate you, and if you see again remind yourself that unless you ate that many calories it isnt a real gain, but also use it to motivate you by telling yourself you'll work hard to see losses in the next few days.  As long as you twist the situation to your benefit even the little water weight gains that everyone has can be a positive thing.