Our bodies digest (break down) the food into tiny molecules or units—primarily “glucose,” the sugar that is the food for each cell in the body. A portion of these digested/broken-down molecular food units can cross the intestinal cell wall if there is a specific carrier and go through a separate circulating system. Simply put, your breakfast, lunch, and supper are broken down and then sent to the liver. The liver is a large, silent, and painless organ that converts your carbohydrates, proteins, and fats primarily into glucose for fuel, some protein as needed, and into fats if you have overeaten. This fat (triglycerides) is transported to storage spots in the body.
The food you eat is simply chemicals—primarily molecules of carbohydrates, fats, and proteins—which are made up of carbons, hydrogen, oxygen, and nitrogen. After you swallow the food, it is shredded and broken apart by the acid in the stomach. It moves in small amounts to the small intestine, where digestive juices—which are produced in the pancreas, gallbladder, and cell walls of the small intestine—are used to break down the carbohydrates, fats, and proteins into even smaller units. These units are moved across the intestinal walls and to the liver—a process taking anywhere from five to twenty minutes. Dietary fats (also called triglycerides) do not go directly to the liver. After crossing the intestinal wall, they take a longer trip, slowly moving between the body’s cells in a space called the lymphatic system. Triglycerides will slowly drip into the regular bloodstream through the various ducts connected to the watery circulating system, and then finally circulate to the liver. This route can take up to 13 hours. The slow entry keeps the blood sugar stabilized as the liver slowly converts the fat into the usable glucose units. If you eat a meal that is primarily carbohydrates, you will be hungry sooner. If you add fats, it will help you go longer before you feel hungry again.