Postprandial means after eating a meal while preprandial is before a meal.

Usages of the term

This term is used in many contexts but also in relation to blood sugar (or blood glucose

Glucose

Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

) levels, which are normally measured 2 hours after and before eating in a postprandial glucose test. For example, the American Diabetes Association

American Diabetes Association

The American Diabetes Association is a United States-based association working to fight the consequences of diabetes, and to help those affected by diabetes...

 recommends a postprandial glucose level under 180 mg/dl and a preprandial plasma glucose between 70-130 mg/dl. However, this is not the only context in which this term is used.

• Postprandial hyperglycemia
  Hyperglycemia
  Hyperglycemia or Hyperglycæmia, or high blood sugar, is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a glucose level higher than 13.5mmol/l , but symptoms may not start to become noticeable until even higher values such as 15-20 mmol/l...
  
   (PPHG) is high blood sugar following a meal. It can be evaluated in a postprandial glucose test.
• Postprandial dip
  Postprandial dip
  In medicine and specifically endocrinology, postprandial dip is a term used to refer to mild hypoglycemia occurring after ingestion of a heavy meal....
  
   is a mild decrease in blood sugar after eating a big meal.
• Postprandial hypotension
  Hypotension
  In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
  
   is a drastic decline in blood pressure which happens after eating a meal.
• Postprandial regurgitation
  Regurgitation (digestion)
  Regurgitation is the expulsion of material from the mouth, pharynx, or esophagus, usually characterized by the presence of undigested food or blood.Regurgitation is used by a number of species to feed their young...
  
   is a unique symptom of rumination syndrome.
• Postprandial thermogenesis
  Thermogenesis
  Thermogenesis is the process of heat production in organisms. It occurs mostly in warm-blooded animals, but a few species of thermogenic plants exist.-Types:...
  
   is heat production due to metabolism after a meal, temporarily increasing the metabolic rate.
• Postprandial abdominal distension usually refers to bloating of the abdomen following a meal, especially a large one. It is generally harmless, but tends to be uncomfortable. Instances of its sudden onset or prolonged duration can, however, be symptoms of certain severe adverse gastro-intestinal conditions.
  Postprandial abdominal distension is also a documented side effect of some medications.

Processes in the postprandium

In the postprandium, there is digestion

Digestion

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

 of food in the gastrointestinal tract

Gastrointestinal tract

The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

, followed by uptake and various metabolic processes, mainly anabolic ones (building organic molecules from smaller units). The postprandium is characterized by an increased activity of the parasympathetic nervous system

Parasympathetic nervous system

The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system . The ANS is responsible for regulation of internal organs and glands, which occurs unconsciously...

, putting the body in a state of "rest and digest".