8 lbs. in 1 week=how is it possible?

I've been losing weight steaidly. And i do say, about two times this week i went a little over my calories. and twice i only did crunches and not my usual aerobics(but i was very busy and both those days i ate less than 1200 calories) and now suddenly i'm 128-129 and last week i was 121!!! i have been lifting weights but is it possible that i gained 8 pounds in muscle! i mean i think at the very most i would have stayed the same or up 1 pound-but 8? can anyone explain this. Now it's going to take me 2 months to get back down! my confidence is shredded and my goals seem harder and harder to get to.

I can't explain 8 pounds but I did (and sometimes still do by the way my pants fit) have a 6 pound gain like that.   For me it started once I got into my thirties.  Being pre-menstrual (one week before), I began to notice that my body retained food (less trips to the washroom) and the fluid (bloat) would build up in me much more.  No amount of exercising, etc would change this.  I now don't weigh in anymore until I have reached the end of my period (2 days after my last day).   My advice is stay consistent.  It sounds like you are following a healthy pattern.

Hey :)  One thing for sure, you can't eat less than 1200 calories! Your body goes into starvation mode and it is very possible that your body started hording what you were eating and could have resulted in the extra weight.  There is also a chance that some of the weight you have lost was water weight, make sure to always weigh yourself at the same time of the day because your weight varies throughout the day.  And lastly, it's definitely possible that you gained a little from muscle lifting, although not the enirety of the 8 lbs.  My guess is that the combination of all the things you described, and what I've listed here are what caused you to have the jump.  Just keep doing what you are doing - workout and make good food choices and the results will keep coming - the scale is great and all, but even following it on a weekly basis can give you false excitement in weight lost, and false disappointment with "gained" weight, the best gauge is how your clothes fit! And promise me you'll eat at least 1200 calories a day!!  Anyways, best of luck and keep your chin up, you are doing great:)

mkc8222- thank you for all the encouragement. i took a break from weight-lifting this week  so see if my weight changed and i do check it every thrusday morning(though i am going to skip this thrusdya making it every other thursday morning). I am definetely going to try really hard to eat 1200 calories!! Sometime sits hard to convicne myself its the right thing to do.