Any time a dog has a sudden change in behavior, it is best to see the vet to rule out medical issues.
If your dog was previously a voracious eater and is suddenly turning her nose up at food, a trip to the vet is in order... asap.
Also, a healthy dog will not starve themself. Stop giving in and adding "extras" to her food to entice her to eat. The more frequently you give in, the more she will expect it. Done often enough, she will learn that if she doesn't eat her "boring" food and you will always dress it up. Unless you plan to home-cook her food or continue adding things forever, stop this behavior before it becomes habit. It may take a few days (though I have never had a dog hold out longer than 2) but it is a fairly easy habit to break. I've done this a ton of times with fosters that were considered picky eaters and others that were free-fed, and it works every time.
Measure out her breakfast into her bowl. I like to do this with the dog in the room so they see me getting their food.
While holding the bowl of food (even giving it a little shake to rattle the food around) have her do some very simple commands. Make sure the commands are ones she is really good at. If all she knows really well is sit, just do that. Only have her do the command 1-2 times at first, gradually increasing the number and difficulty over time.
Once she has successfully completed her task, mark the behavior (with a clicker or verbal cue like yes), and put her food bowl down and say (something like) ok, eat.
If at this point she doesn't eat her food, leave it down for no more than 15 minutes, then pick it up and put it away. Don't give in now or later and slip her treats or people food. Unless you are trying to put weight on an emaciated dog or the dog has other health issues, they aren't going suffer any ill effects from missing a meal.
Do the same thing all over again with her dinner (at dinner time).
Most dogs will eat at this point. I've only had 2 hold out longer, and that was mostly because they hàd years of habit to break. By the next morning they ate, and ate every time I put the bowl down. A few needed to have the senario repeted a couple mornings in a row, but they quickly realized that if they didn't eat what/when I fed them they weren't going to get anything else.
The sooner you begin to alter the behavior, the easier it is to fix. The most "stubborn" dogs I have worked with have had the longest amount of time (in a few cases 5 years or more) to develop their habits.