Absorptive state of metabolizing is the act of being fed. It is when you are feeding your body and it is synthesizing the nutrients into things your body can use.
Post- Absorptive state of metabolizing is when your body is fasting. After a few hours of eating when everything is synthesized. You're body is getting less nutrients from the food, so it needs to get nutrients from itself. It starts the process of catabolism, which is the breakdown of nutrients into smaller intermediate parts to use for the body.
In absorptive state, the body starts by using glucose as the major energy source. It is either converted into glycogen or fat (both of which can be stored in the body). In this state, two major nutrients can be synthesized. Lipids and proteins. For lipids, the body starts by using lipase (a protein thats function is to break apart lipids) to hydrolyze (break down) lipids in muscle and fat tissues. You are left with glycerol and fatty acids and those are converted into triglycerides for storage. Then the triglycerides are used by adipose (fat) tissue, liver, and skeletal and cardiac muscle as a primary energy source. For proteins, excess amino acids are deanimated (over abundance of proteins leads to break down) and used for ATP (energy) synthesis, or stored as fat in the liver. But most amino acids are used to re-synthesize proteins. All of this is controlled by the hormone insulin- its primary function is to lower blood glucose level (hypoglycemic hormone)
In Post absorptive state, the body makes glucose available to the blood and promotes use of fats for energy. The main goal here is to maintain blood glucose level in between meals. First th body will go through what is called glycogenolysis. This is glycogen breakdown. Glycogen is the first substance broken down in times of fasting. First the body takes glycogen from the liver, then skeletal muscle. If that runs out, the body will start to break down fat (lipolysis) in adipose tissues and the liver. Glycerol is used for glucogenesis (use of a non carbohydrate to form glucose- the main energy source). If we run out of fats - which at this point the body is in severe danger of organ failure, fat holds organs in place and helps insulate them- then lastly we breakdown proteins. This is the last step, muscle begins to break down. All of this is controlled by the hormone glucagon- its primary function is to raise blood glucose lever (hyperglycemic hormone)