Around 1850s, Justus von Liebig found that the human body contains many substances present in food and that body fluids contain more sodium and less potassium than tissues.
The average human body contains about 20 % of fat, 15% protein, much smaller amounts of carbohydrate (perhaps I %) and large amounts of water.
Although fat is found primarily in adipose tissue, intracellular triglyceride pools are also observed in liver, skeletal muscle and other organs, particularly in pathological conditions such as hepatic steatosis and various forms of lipidosis.
Human body also contains substantial amounts of the “major minerals,” from calcium and phosphorus down to sulfur and magnesium as well as trace quantities of most elements.
The water content of the human body is never higher than at birth – about 70% of a term newborn infant’s weight may be water.
By adulthood, body water content is generally 56 to 64%. As the water content of the extracellular fluid is by and large controlled hormonally, the greatest influence upon tissue water content remains the ration of skeletal muscle to adipose tissue.
The human diet reflects this compositional need, and consists of large quantities of water containing, proteinaceous, fatty, and carbohydrate foods, as well as others rich in the minerals.
Human body composition
