Actually, it is really great that she is eating ANYTHING so soon. My husband and I took a couple females from the shelter we volunteer with after they were spayed, and it took them almost two days to start eating again. I was trying everything to get them to eat but it was very hard. One of the tricks I learned was to break the stems of the parsley in half so that the smell was more potent, this seemed to help get them more in the mood to eat. She is probably uncomfortable right now, it takes them awhile to start to feel like themselves again. I would recommend just keeping trying to hand feed her some veg, give her a treat here and there to stimulate her appetite, and just give her lots of pets to comfort her.
Have you lifted her up to check on her spay incision? My vet recommended doing that at least once a day to make sure that it was not infected or bleeding – I know it isn’t easy to do, but you don’t have to pick her all the way up, you can try just lifting her front end up until you can see her tummy. it is normal for it to be red, and have some dried blood, but check for swelling or abnormal colors or anything else that doesn’t look right.