Pre-Op: Unexpected Weight Gain

I am pre-op (going through a very frustrating insurance experience) but I've been losing weight since January 1st.  I eat somewhere between 1100-1400 calories a day, 90-100+ grams of protein, and I try (and I'm almost always successful) to keep carbs under 80 grams.  I average about 120-140oz of water every day.  As of Monday morning, I had lost 40lbs and I'm feeling pretty good about getting myself under control even though I no longer have any idea when surgery will happen.  I weigh myself every morning to get an idea of trends in my weight loss but I only log my weight once a week.  Last week, I joined a gym and met with a trainer to come up with a program to use until surgery.  I started Monday night.  I basically did about 45 minutes of cardio (treadmill, bike, and elliptical).  Tuesday morning, I had a weight gain of 5lbs.  I did the same cardio routine last night and this morning I am up an additional 2.5lbs.  I've been searching for possible causes and have read a few posts that this could be water retention by my muscles.  This seems logical to me but I guess I just want to hear some confirmation from some of the experts in this forum.  I'm not discouraged or ready to give up - I will stick to this program!  I just wanted some validation, I guess.

Thanks for any input!! 

Relax - it's water, pure and simple.  When you go from doing nothing physically to exercising, your body automatically grabs onto tha****er to cushion the muscles (I'm keeping this simple although there are some other physiological things going on too).   Anyway, as soon as your muscles get into a routine you will dump all that excess water.  

You are NOT gaining weight; you are NOT gaining fat.  It's physically impossible to gain 5 lbs. of fat in a single day.  This is all water.  STOP weighing yourself every day until you've gotten into an exercise routine for 2-3 weeks.  Otherwise you will drive yourself bonkers.  

You are doing GREAT! 

Thank you, Tracy!  I'm actually not freaking out about it which is a positive step for me.  Before I made the commitment to treat myself and my body with the respect I/it deserves, a blip like this would have sent me back to carb heaven!  But now I'm feeling ok with it....almost like it's a curiosity more than any kind of failure.  I'm mostly trying to get more information on how my body works so that when I experience similar things after surgery, I can deal with them somewhat rationally.  Thank you for the validation!

You have a good attitude...keep it up :)

You have a good attitude...keep it up :)

Thank you!

Agree with Tracy.  I noticed the same impact over time.

You're good!  That 2.5 lbs is going to be a distant memory!

One positive from this experience is that you learn to deal with a reversal or a stall.  That happens to all of us after surgery.  The more you learn to deal with it, the better off you will be.  It looks like you had a chance to see a small reversal first hand.... that will servce you well after surgery!

Thank you.  That is precisely why I wanted to start making changes before surgery.  I have read so much on OH and tried to take as much of it to heart as possible.  I'm definitely grateful for those who have shared their experiences on this forum!

as others have said, it's definitely water weight.

i've been struggling a lot with water weight.  i even gained 5.8lbs during my 3rd week post op!!!  i've since been prescribed a diuretic which helps some.  hopefully you'll only have to contend with this while your muscles are getting accustomed to exercise.