Does chewing and spitting have a gray area?

I know its bad when practiced with all foods, but you know it makes sense when you want to taste a really delicious but bad for you food. Why not just taste the apple pie then spit it out avoiding the period of regret you feel for falling off the diet wagon? And on that note is any nutrients or calories ingested right from the mouth or does food have to reach the stomach for nutrients and calories to be utilized?