Re: Why does peanut butter stick to the roof of your mouth?

Peanut butter is approximately 25% protein, 50% fat, 1% moisture and the balance salt and carbohydrates. The high protein content gives the peanut paste good adhesion.

Because of the high fat and low moisture content, the butter is not easily diluted by saliva. ("Oil and water don't mix!")

The combination makes it difficult to get the stuff off of your velar surfaces ("the roof of your mouth").

If you put a spoonful of crisco or lard in your mouth, you will experience a similar phenomenon, although it won't 'stick' as much, since the protein is absent.