The mouth

Lift your fork to your mouth, and your teeth and salivary glands swing into action. Your teeth chew, grinding the food, breaking it into small, manageable pieces. As a result:

• You can swallow without choking.
• You break down the indigestible wrapper of fibers surrounding the edible parts of some foods (fruits, vegetables, whole grains) so that your digestive enzymes can get to the nutrients inside. At the same time, salivary glands under your tongue and in the back of your mouth secrete the watery liquid called saliva, which performs two important functions:
• Moistening and compacting food so that your tongue can push it to the back of your mouth and you can swallow, sending the food down the slide of your gullet (esophagus) into your stomach.
• Providing amylases, enzymes that start the digestion of complex carbohydrates (starches), breaking the starch molecules into simple .

No protein digestion occurs in your mouth, though saliva does contain very small amounts of lingual lipases, fat-busting enzymes secreted by cells at the base of the tongue; however, the amount is so small that the fat digestion that occurs in the mouth is insignificant.