Um, I'm reading razzle's response, and thinking to myself, yup, yepper, that's right all the way through. I have a few things to add though.
First, your metabolic/ calorie needs are higher during the healing process. Lots of repair and rebuilding going on during the early weeks post-op.
Second, you NEED more carbs post-op. I have no doubt that you lost a fair bit of blood during the surgery, and some bleeding/ drainage afterward. Red blood cells are one of the few tissues in the body which require glucose specifically as the energy source for their production. For the average lowcarber, a 20 gram level will meet their needs, and any extra glucose can be made in the lvier from protein, by the process of
gluconeogenesis. But, for an acute loss of blood, such as surgery, you will need more glucose available to replenish what has been lost. It takes approx. 4 weeks to replenish your store of red cells. It's possible that in time you may find you require fewer carbs than you do now
Blood lost through surgery or trauma is a different situation from giving a blood donation, where the person is able to eat and drink immediately after, and no other healing to take place in the body.
Razzle has a good point about eating more carbs from veggies, as opposed to other carbs. I've found myself to be stalled at a very low carb level, where the carbs came from dairy, processed meats, artificial sweeteners (15g ECC per day). Yet, weight loss would resume with a higher carb intake, when they came mostly from vegetables (25 to 30g ECC per day).
Losing inches from the waist may be due also to water-bloat loss. Pre-op, you were taking NSAID and COX-inhibitors for pain and inflammation. Those drugs are notorious for causing fluid retention.
Another reason, not as happy or upbeat .. is that you've likely lost some muscle mass in your hip and leg on the surgical side. Not a lot, but some. You've not been weight-bearing or using that leg for 3.5 weeks. I imagine that you are doing some isometric strengthening exercises to keep atrophy at a minimum, but loss of muscle tissue is seen as little as 48 hrs after being immobilized.
As well, until the muscle has healed and reattached itself to the bone (it would've been surgically cut and moved aside to facilitate removing the diseased hip joint, and the prosthesis cemented in place) there won't be a lot of regrowth of muscle tissue taking place.
It may be a combination of a lot of factors, or only a few. Take each day as it comes, and be open to changing the routine as time goes on, and you're able to be more active.
Glad you're on the mend
Doreen