A small amount of lipase is also secreted in the stomach to continue the digestion of fat; however most fat digestion continues in the small intestine where the fat is mixed with bile. Your liver produces the bile which is stored in the gall bladder until you eat fats. Bile works like a detergent to emulsify the fats into smaller droplets. This makes it easier for more lipase to get to the triglycerides. This third type of lipase is made by the pancreas and secreted into the small intestine.
The bile and lipase break down the fats into smaller pieces which can be absorbed from the small intestine into the blood stream. The bile, which contains cholesterol, is either re-absorbed into the blood or bound by soluble fiber in the intestine and eliminated in the stool. Eating foods with lots of soluble fiber helps keep your cholesterol levels healthy by grabbing more of the cholesterol from the bile and eliminating it from your body.
A healthy digestive system will absorb about 95 percent of the dietary fat that you eat. People with malabsorption disorders will not be able to absorb fats properly. Celiac sprue, pancreatic lipase deficiency and bile salt deficiency are three examples.
Fats and oils contain nine calories per gram. Your body will take the extra fatty acids and store them as adipose tissue, better known as body fat. That adipose tissue can be broken down and turned into glucose when you need more calories than you consume. This is why counting calories is important for people who want to lose weight and for people who want to gain weight.
Fat in the DietThe USDA suggests that you get about 30 percent of your calories from fat. For a 2,000 calorie per day diet, that would equal 600 calories from fat. Since fat has nine calories per gram, that would be equal to about 67 grams of fat. You should watch your cholesterol and saturated fat intake as well. The USDA suggests no more than 300 mg cholesterol each day, less than 10 percent of your daily calories from saturated fat and less than one percent from trans-fats.
A typical Western diet often includes much more than that because fats add texture and flavor. Fats also slow down gastric emptying, so high fat meals are more satisfying. Unfortunately, that means too many calories for a lot of people.
Short Chain Fatty AcidsRemember reading about fiber in the carbohydrate lesson? Your body can't digest fiber. That's good for adding bulk to the stool, however, fiber also has one other important function. The friendly bacteria that live in your colon ferment the fiber and produce short chain fatty acids. They are called short chain fatty acids because they only have two to four carbons in their chains. They are easily absorbed into the walls of the colon, help keep the colon tissue healthy and can reduce inflammation.
This is important for everyone, but especially for people with inflammatory bowel diseases. The short chain fatty acids may help heal the intestinal walls. Having sufficient amounts of short chain fatty acids in the intestinal tract may also help prevent colon cancer.