I had surgery 12/17. The next day I was up 2 lb's. I am faithfully following the liquid diet. Finally today I have lost 5lb's, including the 2 I gained. Can someone tell me why I gained initially? How long before I start losing?

Likely they filled you up with IV fluids while in the hospital, I had the same problem but after 3-4 days it disappeared plus a little extra went with it.

I think it's because of the anesthesia and iv. There is swelling after the surgery also.

Its very common to 'gain' in the hospital due to the IV fluids and swelling. I'm surprised more surgeons don't warn their patients about this. Of course, it is just retained fluid weight so you can expect to lose that (plus some real weight) within about a week of getting home. Just drink drink drink your water. The more you drink, the less water you retain. Your body will let it go as soon as it sees it has an endless supply coming in.

During surgery, they put 3 bags of saline solution in me. In the first few days after the surgery, I hardly urinated at all. I actually had to push it out, and I've never done that before in my life.

But after a few days, once I was able to start drinking normally again, I rid myself of the extra fluids and the Water weight.

Now I need to start adding the exercise back into my routine to help with the weight loss, even though my calorie intake isn't that high.

I gained overnight after surgery too. I think it was just water weight gain??

I had lost 15 pounds the week following surgery due to dehydration, however...once I got straight i gain almost all that back and never lost it. I went back to Surgeon for first fill last Wednesday, i weighed myself this morning and I have lost 16 lbs. Obviously I have not lost 16 TRUE pounds in 6 days but I think my body just needed to adjust. The doctor was not concerned when I saw him and said it is perfectly normal. Good Luck and give yourself a chance!