why diarrhea post op but constipation after?

I was just wondering, why the diarrhea when you do the liquid post op diet but then constipation with the only liquid diet after surgery? Why wouldnt it be diarrhea for both? What changes since even a couple of weeks after the surgery your still only drinking liquids??/

For me the meds caused the diarrhea when I stopped meds, no more diarrhea

There are two separate causes of constipation post-op. The one you may be thinking of - a high protein, low carb diet - really does tend to only kick in with solids.

The other cause, however, is many pf the narcotic pain relievers like the pump they give you in the hospital and the prescription many folks come home on. Due to my surgeon's plan I was (TMI) completely empty when I went into the hospital and was unable to take the pain meds when I got home because I was allergic. As a result, I never had the immediate post-op constipation. Mine didn't start until I was on solids.

 I seemed to vascilate between one extreme or the other, especially the first weeks post-op -- liquid in = liquid out.  However, a protein-loaded diet, not enough fiber, and not getting at least 64 oz liquid tends to bind things up.  I know I'm still not drinking enough, but I've started using Benefiber to help keep things regular. 

I think that the constipation can be narcotic pain medications if you're still taking them.  OR lack of fiber.  I had terrible time with constipation until I started taking a fiber supplement every single day.  Now i'm totally regular.   I had diarrhea in the early post op time and I just assumed it was liquid in/liquid out thing.  However, some people are more affected by the narcotic pain medication so may have more of an issue with constipation during that time.
Amy