Losing weight after surgery can be very difficult. It is hard to lose weight when there is not the ability to be as active as you typically are.
One way to make sure that you are losing weight is to closely monitor what you are eating and how you are being active. Being as active as possible without the possibility of being injured is always a good idea as there is no reason to become injured after surgery.
A good note is that any movement or activity that causes pain in the area or the area directly surrounding where you had surgery is not a good sign and should be discontinued. Just eat green leafy vegetables everyday if you find it hard to exercise or move around in the house.
Another good thing to do is to watch your intake and calorie consumption.
It is important to really watch what you are eating and to monitor that you are eating the right types of food for being less active. This typically means higher levels of fiber and less starches.