I don't like when they don't eat, but I remind myself that they fast for 8 - 12 hours before surgery, so for the average dog that must be safe.
Plus, you have the Nutrical or Karo on hand just in case.
Be sure to hold all treats and chews until she eats.
Put her food down and don't make a big deal out of it, otherwise she will pick up on your anxiousness and maybe think there is a reason to not eat what is in the bowl. You can always do tricks and use her food as reward too.
With my guys, the more I force them to do something, the more likely they are to not want to do it. I have trick them into thinking everything is their idea.
Best wishes.