Not chewing well can actually make you sick. Chewing is extremely important to proper digestion. The chewing reflex is what signals the body to release saliva. Saliva is important to digestion because it helps liquefy your food so your gut can assimilate it, and also because it contains the salivary enzyme ptyalin, a form of amylase, which begins the process of carbohydrate digestion.
The parotid glands behind the ears also signal the thymus gland to produce T-cells just in case the food contains toxins or pathogens, which is helpful if your food is contaminated in any way.
The ultimate goal of the process is to deliver food to the stomach in a liquid state and free of toxins. It is recommended to chew each bite 25 to 50 times -- especially when eating foods high in carbohydrates such as grains, sugars, and starches.
In addition to always chewing your food thoroughly, try to avoid standing, watching TV, reading, arguing, or doing something that requires concentration while you eat. These activities distract you and produce a higher heart rate than if you are sitting down and relaxing as you eat, which means you will be less likely to chew each bite enough times. It also means less blood will be available to your gut for proper and thorough digestion.
I have heard of many cases of IBS (Irritable Bowel Syndrome), autoimmune diseases general stomach aches and abdominal bloating be alleviated simply by increasing the number of times a person chews his or her food!