How the body uses fat
Our body uses glucose, glycogen and fat as main sources of energy, which can convert one to the other. Fat is mainly used as energy storage.
Endogenous Fat
Once dietary fat is absorbed, it joins the endogenous fat. The adipose tissue in the key organ for storing fat. Liver is also important for storing it in circulation. The liver converts fat to sugar and back, releases fat and cholesterol and synthesizes molecules
Sources of energy
Glucose: primary energy source for all tissue. Obtained by direct ingestion and digesting complex sugars. It is transported through blood.
Glycogen: complex carbohydrate made of thousands of glucose molecules. Stored in liver and muscles, low energy reserve.
Fat: Primary long term source of stored energy, It's molecule is called triglyceride. It is insoluble in blood.
Metabolic pathways of fat and sugar (fat and sugar can be converted into each other by enzymatic reactions)
Transporting fat
Sugar to fat: Muscles and liver convert excess glucose to glycogen, any further excess is converted to triglycerides and stored
Fat to sugar: Triglycerides are broken down to glycerol and fatty acids
Digestion of fat
Ingested as food, subjected to mechanical digestion, fats form droplets after broken, which are absorbed in the small intestine, after absorption, it is transported to other organs to it's storage
Emulsification:fat droplets enter the duodenum, bile acids are added, they emulsify them, breaking droplets into smaller ones.
Chemical: Pancreatic juices added to the duodenum. Pancreatic lipase digest triglycerides, converting them into two fatty acids and a monoglyceride
Lipoproteins: cel membranes with a phospholipid bilayer create a hydrophilic interior
Absorption and packaging: Fatty acids absorbed by the microvillilining and reassembled by triglycerides, which are packed into chylomicrons, which are released into the lymphatic system and enter blood circulation
Fate of ingested fat: Chylomiicrons activate protein lipase, breaking down triglycerides. Fat absorbed by fat tissue is stored, ny muscle is burned for energy
Lipoprotein structure: Apoliproteins stimulate enzymes that allow lipoproteins to be recognized by certain receptors
Lipoprotein diversity: named according to density 
Lipoprotein functions
Lipoproteins and health: Excess cholesterol from the body is taken up by HDLs which return to the liver. They are rich in cholesterol, corelating with heart disease. The ratio of LDL to HDL can be healthy or unhealthy
Albumin: is synthesized din the liver, most abundant protein in the blood, each one carries seven fatty acids, used for energy or conversion to other molecules
Intracellular transport: long chain fatty acids are insoluble in a cell's cytoplasm, within which FABPs transport fatty acids by encapsulating them
The liver converts sugar to fat and glycogen , triglycerides are released in VLDSs. Fatty acids are assembled to triglycerides for storage
Burning fat: The liver and muscles convert their stored glycogen to glucose for immediate energy
Keaton bodies are a group of molecules that includes acetoacetate and D-ß-hydroxybutyrate, during starvation, ketone bodies become an important source of energy for the brain
Reference:
Ronald, M & Jeffrey M. (2004) How the body uses fat Retrieved April 25, 2018 form HHMI BioInteractive Web Site: http://www.hhmi.org/biointeractive/how-body-uses-fat
Carlos Emilio Ramos Barrios A01745611