Fat Digestion

3. Fat Digestion

Fat digestion takes much longer than the digestion of carbohydrates and somewhat longer than the digestion of proteins. A raw salad consisting of nonstarchy vegetables can be digested within two to three hours. When free fats such as corn, sesame, peanut or other oils are added to the salad, digestion is delayed for another two or three hours.

Coating our food with free oils inhibits the natural digestive processes by preventing digestive juices access to these foods until the oils are digested. Consequently, by the time the oils or fats surrounding the other food particles are digested, the elementary carbohydrates or proteins in the vegetables have begun to ferment (carbohydrates) or putrefy (proteins) in the stomach.

3.1 Fats Require Special Digestion

Free fats, unlike carbohydrates, require special digestive action before absorption. This is because the end products of all digestion are carried in a water medium (that is, the blood and lymph). Free fats are not soluble or transportable in these water mediums until they undergo special changes.

After fats leave the stomach, they enter the duodenum of the small intestine. Their presence causes the stimulation of the gallbladder, which forces bile down into the small intestine. The bile emulsifies, all the fats in the intestines.

The emulsified fats are then split by enzymes into fatty acids and glycerol. At this point, the fats can be absorbed through the intestinal mucosa. During absorption, the fatty acids and glycerol recombine with a small amount of protein to form microscopic particles of fat called chylomicrons.

The fats in the form of chylomicrons are now soluble enough to enter lymph circulation. The fatty acids are converted to the liver to acetate or ketone bodies as an energy source for the cells.

The fat which is not used immediately for the body’s energy needs is stored primarily in adipose tissue. Adipose tissue is a special kind of tissue (found mainly around the stomach, thighs and buttocks) which contains the necessary enzymes to continually produce and release new fat to meet the body’s needs.