What do fats become after digestion

Before the prepackaged food industry, fitness centers, and weight-loss programs, our ancestors worked hard to even locate a meal. They made plans, not for losing those last ten pounds to fit into a bathing suit for vacation, but rather for finding food. Today, this is why we can go long periods without eating, whether we are sick with a vanished appetite, our physical activity level has increased, or there is simply no food available. Our bodies reserve fuel for a rainy day.

One way the body stores fat was previously touched upon in the Carbohydrates chapter. The body transforms carbohydrates into glycogen that is in turn stored in the muscles for energy. When the muscles reach their capacity for glycogen storage, the excess is returned to the liver, where it is converted into triglycerides and then stored as fat. In a similar manner, much of the triglycerides the body receives from food is transported to fat storehouses within the body if not used for producing energy.

The chylomicrons are responsible for shuttling the triglycerides to various locations such as the muscles, breasts, external layers under the skin, and internal fat layers of the abdomen, thighs, and buttocks where they are stored by the body in adipose tissue for future use. How is this accomplished? Recall that chylomicrons are large lipoproteins that contain a triglyceride and fatty-acid core. Capillary walls contain an enzyme called lipoprotein-lipase that dismantles the triglycerides in the lipoproteins into fatty acids and glycerol, thus enabling these to enter into the adipose cells.

Once inside the adipose cells, the fatty acids and glycerol are reassembled into triglycerides and stored for later use. Muscle cells may also take up the fatty acids and use them for muscular work and generating energy. As the body calls for additional energy, the adipose tissue responds by dismantling its triglycerides and dispensing glycerol and fatty acids directly into the blood.

Upon receipt of these substances the energy-hungry cells break them down further into tiny fragments. These fragments go through a series of chemical reactions that yield energy, carbon dioxide, and water. Lipoproteins are characterized by size, density, and composition. As the size of the lipoprotein increases, the density decreases. Mechanical digestion occurs as your teeth grind food and break it apart into smaller pieces. Chemical digestion takes place as lingual lipase, an enzyme in your saliva, begins to emulsify fat and saliva moistens the food to make it easier to swallow.

When the food reaches your stomach, the muscles there begin to churn and move to further break it down. Once it leaves the stomach, the food has become a semi-liquid substance referred to as chyme. The small intestine is the main site for absorption of nutrients and the digestion of fat. When chyme enters the duodenum -- the upper portion of the small intestine -- hormones signal the gallbladder to contract. These contractions push bile, which is made by the liver, out of the gallbladder and into the common bile duct, which connects the gallbladder to the small intestine.

Bile contains bile salts, lecithin, and substances derived from cholesterol so it acts as an emulsifier. It attracts and holds on to fat while it is simultaneously attracted to and held on to by water. Emulsification increases the surface area of lipids over a thousand-fold, making them more accessible to the digestive enzymes.

Once the stomach contents have been emulsified, fat-breaking enzymes work on the triacylglycerols and diglycerides to severe fatty acids from their glycerol foundations.

As pancreatic lipase enters the small intestine, it breaks down the fats into free fatty acids and monoglycerides. Yet again, another hurdle presents itself.

How will the fats pass through the watery layer of mucus that coats the absorptive lining of the digestive tract? As before, the answer is bile. Bile salts envelop the fatty acids and monoglycerides to form micelles.

Micelles have a fatty acid core with a water-soluble exterior. This allows efficient transportation to the intestinal microvillus. Here, the fat components are released and disseminated into the cells of the digestive tract lining. Figure 4. Just as lipids require special handling in the digestive tract to move within a water-based environment, they require similar handling to travel in the bloodstream. Inside the intestinal cells, the monoglycerides and fatty acids reassemble themselves into triacylglycerols.

Triacylglycerols, cholesterol, and phospholipids form lipoproteins when joined with a protein carrier. Lipoproteins have an inner core that is primarily made up of triacylglycerols and cholesterol esters a cholesterol ester is a cholesterol linked to a fatty acid. The outer envelope is made of phospholipids interspersed with proteins and cholesterol. Together they form a chylomicron, which is a large lipoprotein that now enters the lymphatic system, bypassing the liver, and will soon be released into the bloodstream via the jugular vein in the neck.

Entrance into the bloodstream can last up to 14 hours with the peak 30 to 3 hours post-meal. A review argues scientists should focus on designing drugs to lower…. How does the body digest fat? Medically reviewed by Alana Biggers, M. Fat digestion Hard-to-digest fats Improving fat digestion Summary Fats are a type of lipid that is vital for health.

Fat digestion. Share on Pinterest F. Which fats are the hardest to digest? Improving fat digestion. Latest news Could 'cupping' technique boost vaccine delivery? Scientists identify new cause of vascular injury in type 2 diabetes.

Adolescent depression: Could school screening help? Related Coverage. What are the most healthful high-fat foods? Medically reviewed by Natalie Olsen, R. Types of fat: Can fat be good for you? Ways to improve digestion.