When it comes to feeding, I treat my dogs the same way I did my children. Here is your meal. If you don't want to eat it, you will need to wait until the next meal. Not that I feed the same item - just I'm not going to prepare something special until you decide you like it. 

Right now, there is a turkey neck in the back yard that Beardie isn't eating. No problem. I will likely give him something else at dinner.
If your dog turns up their nose at the occasional meal, it's not a big deal if they are healthy. Sometimes refusing food can be in indication of a more serious issue. With an upset tummy (which happens to all of us) you will often see other signs as well such as lethargy, loose stools, grass eating (helps them to throw up).
If it goes on for more than a couple of days, a vet check is in order.